,
RStudio [cph],
R Consortium [fnd]| Title: | Testing DBI Backends |
|---|---|
| Description: | A helper that tests DBI back ends for conformity to the interface. |
| Authors: | Kirill Müller [aut, cre] ,
RStudio [cph],
R Consortium [fnd] |
| Maintainer: | Kirill Müller <[email protected]> |
| License: | LGPL (>= 2.1) |
| Version: | 1.8.1.9016 |
| Built: | 2024-11-21 06:31:47 UTC |
| Source: | https://github.com/r-dbi/dbitest |
A helper that tests DBI back ends for conformity to the interface.
The two most important functions are make_context() and
test_all(). The former tells the package how to connect to your
DBI backend, the latter executes all tests of the test suite. More
fine-grained test functions (all with prefix test_) are available.
See the package's vignette for more details.
Kirill Müller
Useful links:
Report bugs at https://github.com/r-dbi/DBItest/issues
Create a test context, set and query the default context.
make_context( drv, connect_args = NULL, set_as_default = TRUE, tweaks = NULL, name = NULL, default_skip = NULL ) set_default_context(ctx) get_default_context()make_context( drv, connect_args = NULL, set_as_default = TRUE, tweaks = NULL, name = NULL, default_skip = NULL ) set_default_context(ctx) get_default_context()
drv |
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connect_args |
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set_as_default |
|
tweaks |
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name |
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default_skip |
|
ctx |
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[DBItest_context]
A test context, for
set_default_context the previous default context (invisibly) or
NULL.
make_context( new( "DBIConnector", .drv = RSQLite::SQLite(), .conn_args = list(dbname = tempfile("DBItest", fileext = ".sqlite")) ), tweaks = tweaks( constructor_relax_args = TRUE, placeholder_pattern = c("?", "$1", "$name", ":name"), date_cast = function(x) paste0("'", x, "'"), time_cast = function(x) paste0("'", x, "'"), timestamp_cast = function(x) paste0("'", x, "'"), logical_return = function(x) as.integer(x), date_typed = FALSE, time_typed = FALSE, timestamp_typed = FALSE ), default_skip = c("roundtrip_date", "roundtrip_timestamp") )make_context( new( "DBIConnector", .drv = RSQLite::SQLite(), .conn_args = list(dbname = tempfile("DBItest", fileext = ".sqlite")) ), tweaks = tweaks( constructor_relax_args = TRUE, placeholder_pattern = c("?", "$1", "$name", ":name"), date_cast = function(x) paste0("'", x, "'"), time_cast = function(x) paste0("'", x, "'"), timestamp_cast = function(x) paste0("'", x, "'"), logical_return = function(x) as.integer(x), date_typed = FALSE, time_typed = FALSE, timestamp_typed = FALSE ), default_skip = c("roundtrip_date", "roundtrip_timestamp") )
spec_arrow_append_table_arrow
dbAppendTableArrow() returns a
scalar
numeric.
If the table does not exist,
or the new data in values is not a data frame or has different column names,
an error is raised; the remote table remains unchanged.
An error is raised when calling this method for a closed
or invalid connection.
An error is also raised
if name cannot be processed with DBI::dbQuoteIdentifier() or
if this results in a non-scalar.
SQL keywords can be used freely in table names, column names, and data. Quotes, commas, spaces, and other special characters such as newlines and tabs, can also be used in the data, and, if the database supports non-syntactic identifiers, also for table names and column names.
The following data types must be supported at least,
and be read identically with DBI::dbReadTable():
integer
numeric
(the behavior for Inf and NaN is not specified)
logical
NA as NULL
64-bit values (using "bigint" as field type); the result can be
converted to a numeric, which may lose precision,
converted a character vector, which gives the full decimal representation
written to another table and read again unchanged
character (in both UTF-8 and native encodings), supporting empty strings (before and after non-empty strings)
factor (possibly returned as character)
objects of type blob::blob (if supported by the database)
date
(if supported by the database;
returned as Date)
also for dates prior to 1970 or 1900 or after 2038
time
(if supported by the database;
returned as objects that inherit from difftime)
timestamp
(if supported by the database;
returned as POSIXct
respecting the time zone but not necessarily preserving the
input time zone),
also for timestamps prior to 1970 or 1900 or after 2038
respecting the time zone but not necessarily preserving the
input time zone)
Mixing column types in the same table is supported.
The name argument is processed as follows,
to support databases that allow non-syntactic names for their objects:
If an unquoted table name as string: dbAppendTableArrow() will do the quoting,
perhaps by calling dbQuoteIdentifier(conn, x = name)
If the result of a call to DBI::dbQuoteIdentifier(): no more quoting is done
to support databases that allow non-syntactic names for their objects:
The value argument must be a data frame
with a subset of the columns of the existing table.
The order of the columns does not matter.
Other Arrow specifications:
spec_arrow_create_table_arrow,
spec_arrow_fetch_arrow,
spec_arrow_fetch_arrow_chunk,
spec_arrow_get_query_arrow,
spec_arrow_read_table_arrow,
spec_arrow_send_query_arrow,
spec_arrow_write_table_arrow,
spec_result_clear_result
spec_arrow_create_table_arrow
dbCreateTableArrow() returns TRUE, invisibly.
If the table exists, an error is raised; the remote table remains unchanged.
An error is raised when calling this method for a closed
or invalid connection.
An error is also raised
if name cannot be processed with DBI::dbQuoteIdentifier() or
if this results in a non-scalar.
Invalid values for the temporary argument
(non-scalars,
unsupported data types,
NA,
incompatible values,
duplicate names)
also raise an error.
The following arguments are not part of the dbCreateTableArrow() generic
(to improve compatibility across backends)
but are part of the DBI specification:
temporary (default: FALSE)
They must be provided as named arguments. See the "Specification" and "Value" sections for details on their usage.
The name argument is processed as follows,
to support databases that allow non-syntactic names for their objects:
If an unquoted table name as string: dbCreateTableArrow() will do the quoting,
perhaps by calling dbQuoteIdentifier(conn, x = name)
If the result of a call to DBI::dbQuoteIdentifier(): no more quoting is done
The value argument can be:
a data frame,
a nanoarrow array
a nanoarrow array stream (which will still contain the data after the call)
a nanoarrow schema
If the temporary argument is TRUE, the table is not available in a
second connection and is gone after reconnecting.
Not all backends support this argument.
A regular, non-temporary table is visible in a second connection,
in a pre-existing connection,
and after reconnecting to the database.
SQL keywords can be used freely in table names, column names, and data. Quotes, commas, and spaces can also be used for table names and column names, if the database supports non-syntactic identifiers.
Other Arrow specifications:
spec_arrow_append_table_arrow,
spec_arrow_fetch_arrow,
spec_arrow_fetch_arrow_chunk,
spec_arrow_get_query_arrow,
spec_arrow_read_table_arrow,
spec_arrow_send_query_arrow,
spec_arrow_write_table_arrow,
spec_result_clear_result
spec_arrow_fetch_arrow
dbFetchArrow() always returns an object coercible to a data.frame with
as many rows as records were fetched and as many
columns as fields in the result set,
even if the result is a single value
or has one
or zero rows.
An attempt to fetch from a closed result set raises an error.
Fetching multi-row queries with one
or more columns by default returns the entire result.
The object returned by dbFetchArrow() can also be passed to
nanoarrow::as_nanoarrow_array_stream() to create a nanoarrow
array stream object that can be used to read the result set
in batches.
The chunk size is implementation-specific.
Other Arrow specifications:
spec_arrow_append_table_arrow,
spec_arrow_create_table_arrow,
spec_arrow_fetch_arrow_chunk,
spec_arrow_get_query_arrow,
spec_arrow_read_table_arrow,
spec_arrow_send_query_arrow,
spec_arrow_write_table_arrow,
spec_result_clear_result
spec_arrow_fetch_arrow_chunk
dbFetchArrowChunk() always returns an object coercible to a data.frame with
as many rows as records were fetched and as many
columns as fields in the result set,
even if the result is a single value
or has one
or zero rows.
An attempt to fetch from a closed result set raises an error.
Fetching multi-row queries with one
or more columns returns the next chunk.
The size of the chunk is implementation-specific.
The object returned by dbFetchArrowChunk() can also be passed to
nanoarrow::as_nanoarrow_array() to create a nanoarrow array object.
The chunk size is implementation-specific.
Other Arrow specifications:
spec_arrow_append_table_arrow,
spec_arrow_create_table_arrow,
spec_arrow_fetch_arrow,
spec_arrow_get_query_arrow,
spec_arrow_read_table_arrow,
spec_arrow_send_query_arrow,
spec_arrow_write_table_arrow,
spec_result_clear_result
spec_arrow_get_query_arrow
dbGetQueryArrow() always returns an object coercible to a data.frame, with
as many rows as records were fetched and as many
columns as fields in the result set,
even if the result is a single value
or has one
or zero rows.
An error is raised when issuing a query over a closed
or invalid connection,
if the syntax of the query is invalid,
or if the query is not a non-NA string.
The object returned by dbGetQueryArrow() can also be passed to
nanoarrow::as_nanoarrow_array_stream() to create a nanoarrow
array stream object that can be used to read the result set
in batches.
The chunk size is implementation-specific.
The following arguments are not part of the dbGetQueryArrow() generic
(to improve compatibility across backends)
but are part of the DBI specification:
params (default: NULL)
immediate (default: NULL)
They must be provided as named arguments. See the "Specification" and "Value" sections for details on their usage.
The param argument allows passing query parameters, see DBI::dbBind() for details.
immediate argumentThe immediate argument supports distinguishing between "direct"
and "prepared" APIs offered by many database drivers.
Passing immediate = TRUE leads to immediate execution of the
query or statement, via the "direct" API (if supported by the driver).
The default NULL means that the backend should choose whatever API
makes the most sense for the database, and (if relevant) tries the
other API if the first attempt fails. A successful second attempt
should result in a message that suggests passing the correct
immediate argument.
Examples for possible behaviors:
DBI backend defaults to immediate = TRUE internally
A query without parameters is passed: query is executed
A query with parameters is passed:
params not given: rejected immediately by the database
because of a syntax error in the query, the backend tries
immediate = FALSE (and gives a message)
params given: query is executed using immediate = FALSE
DBI backend defaults to immediate = FALSE internally
A query without parameters is passed:
simple query: query is executed
"special" query (such as setting a config options): fails,
the backend tries immediate = TRUE (and gives a message)
A query with parameters is passed:
params not given: waiting for parameters via DBI::dbBind()
params given: query is executed
Other Arrow specifications:
spec_arrow_append_table_arrow,
spec_arrow_create_table_arrow,
spec_arrow_fetch_arrow,
spec_arrow_fetch_arrow_chunk,
spec_arrow_read_table_arrow,
spec_arrow_send_query_arrow,
spec_arrow_write_table_arrow,
spec_result_clear_result
spec_arrow_read_table_arrow
dbReadTableArrow() returns an Arrow object that contains the complete data
from the remote table, effectively the result of calling DBI::dbGetQueryArrow() with
SELECT * FROM <name>.
An empty table is returned as an Arrow object with zero rows.
An error is raised if the table does not exist.
An error is raised when calling this method for a closed
or invalid connection.
An error is raised
if name cannot be processed with DBI::dbQuoteIdentifier() or
if this results in a non-scalar.
The name argument is processed as follows,
to support databases that allow non-syntactic names for their objects:
If an unquoted table name as string: dbReadTableArrow() will do the
quoting,
perhaps by calling dbQuoteIdentifier(conn, x = name)
If the result of a call to DBI::dbQuoteIdentifier(): no more quoting is done
Other Arrow specifications:
spec_arrow_append_table_arrow,
spec_arrow_create_table_arrow,
spec_arrow_fetch_arrow,
spec_arrow_fetch_arrow_chunk,
spec_arrow_get_query_arrow,
spec_arrow_send_query_arrow,
spec_arrow_write_table_arrow,
spec_result_clear_result
spec_result_send_query
dbSendQueryArrow() returns
an S4 object that inherits from DBI::DBIResultArrow.
The result set can be used with DBI::dbFetchArrow() to extract records.
Once you have finished using a result, make sure to clear it
with DBI::dbClearResult().
An error is raised when issuing a query over a closed
or invalid connection,
or if the query is not a non-NA string.
An error is also raised if the syntax of the query is invalid
and all query parameters are given (by passing the params argument)
or the immediate argument is set to TRUE.
The following arguments are not part of the dbSendQueryArrow() generic
(to improve compatibility across backends)
but are part of the DBI specification:
params (default: NULL)
immediate (default: NULL)
They must be provided as named arguments. See the "Specification" sections for details on their usage.
No warnings occur under normal conditions.
When done, the DBIResult object must be cleared with a call to
DBI::dbClearResult().
Failure to clear the result set leads to a warning
when the connection is closed.
If the backend supports only one open result set per connection,
issuing a second query invalidates an already open result set
and raises a warning.
The newly opened result set is valid
and must be cleared with dbClearResult().
The param argument allows passing query parameters, see DBI::dbBind() for details.
immediate argumentThe immediate argument supports distinguishing between "direct"
and "prepared" APIs offered by many database drivers.
Passing immediate = TRUE leads to immediate execution of the
query or statement, via the "direct" API (if supported by the driver).
The default NULL means that the backend should choose whatever API
makes the most sense for the database, and (if relevant) tries the
other API if the first attempt fails. A successful second attempt
should result in a message that suggests passing the correct
immediate argument.
Examples for possible behaviors:
DBI backend defaults to immediate = TRUE internally
A query without parameters is passed: query is executed
A query with parameters is passed:
params not given: rejected immediately by the database
because of a syntax error in the query, the backend tries
immediate = FALSE (and gives a message)
params given: query is executed using immediate = FALSE
DBI backend defaults to immediate = FALSE internally
A query without parameters is passed:
simple query: query is executed
"special" query (such as setting a config options): fails,
the backend tries immediate = TRUE (and gives a message)
A query with parameters is passed:
params not given: waiting for parameters via DBI::dbBind()
params given: query is executed
Other Arrow specifications:
spec_arrow_append_table_arrow,
spec_arrow_create_table_arrow,
spec_arrow_fetch_arrow,
spec_arrow_fetch_arrow_chunk,
spec_arrow_get_query_arrow,
spec_arrow_read_table_arrow,
spec_arrow_write_table_arrow,
spec_result_clear_result
spec_arrow_write_table_arrow
dbWriteTableArrow() returns TRUE, invisibly.
If the table exists, and both append and overwrite arguments are unset,
or append = TRUE and the data frame with the new data has different
column names,
an error is raised; the remote table remains unchanged.
An error is raised when calling this method for a closed
or invalid connection.
An error is also raised
if name cannot be processed with DBI::dbQuoteIdentifier() or
if this results in a non-scalar.
Invalid values for the additional arguments
overwrite, append, and temporary
(non-scalars,
unsupported data types,
NA,
incompatible values,
incompatible columns)
also raise an error.
The following arguments are not part of the dbWriteTableArrow() generic
(to improve compatibility across backends)
but are part of the DBI specification:
overwrite (default: FALSE)
append (default: FALSE)
temporary (default: FALSE)
They must be provided as named arguments. See the "Specification" and "Value" sections for details on their usage.
The name argument is processed as follows,
to support databases that allow non-syntactic names for their objects:
If an unquoted table name as string: dbWriteTableArrow() will do the quoting,
perhaps by calling dbQuoteIdentifier(conn, x = name)
If the result of a call to DBI::dbQuoteIdentifier(): no more quoting is done
The value argument must be a data frame
with a subset of the columns of the existing table if append = TRUE.
The order of the columns does not matter with append = TRUE.
If the overwrite argument is TRUE, an existing table of the same name
will be overwritten.
This argument doesn't change behavior if the table does not exist yet.
If the append argument is TRUE, the rows in an existing table are
preserved, and the new data are appended.
If the table doesn't exist yet, it is created.
If the temporary argument is TRUE, the table is not available in a
second connection and is gone after reconnecting.
Not all backends support this argument.
A regular, non-temporary table is visible in a second connection,
in a pre-existing connection,
and after reconnecting to the database.
SQL keywords can be used freely in table names, column names, and data. Quotes, commas, spaces, and other special characters such as newlines and tabs, can also be used in the data, and, if the database supports non-syntactic identifiers, also for table names and column names.
The following data types must be supported at least,
and be read identically with DBI::dbReadTable():
integer
numeric
(the behavior for Inf and NaN is not specified)
logical
NA as NULL
64-bit values (using "bigint" as field type); the result can be
converted to a numeric, which may lose precision,
converted a character vector, which gives the full decimal representation
written to another table and read again unchanged
character (in both UTF-8 and native encodings), supporting empty strings before and after a non-empty string
factor (possibly returned as character)
objects of type blob::blob (if supported by the database)
date
(if supported by the database;
returned as Date),
also for dates prior to 1970 or 1900 or after 2038
time
(if supported by the database;
returned as objects that inherit from difftime)
timestamp
(if supported by the database;
returned as POSIXct
respecting the time zone but not necessarily preserving the
input time zone),
also for timestamps prior to 1970 or 1900 or after 2038
respecting the time zone but not necessarily preserving the
input time zone)
Mixing column types in the same table is supported.
Other Arrow specifications:
spec_arrow_append_table_arrow,
spec_arrow_create_table_arrow,
spec_arrow_fetch_arrow,
spec_arrow_fetch_arrow_chunk,
spec_arrow_get_query_arrow,
spec_arrow_read_table_arrow,
spec_arrow_send_query_arrow,
spec_result_clear_result
spec_compliance_methods
A backend defines three classes,
which are subclasses of
DBI::DBIDriver,
DBI::DBIConnection,
and DBI::DBIResult.
The backend provides implementation for all methods
of these base classes
that are defined but not implemented by DBI.
All methods defined in DBI are reexported (so that the package can
be used without having to attach DBI),
and have an ellipsis ... in their formals for extensibility.
spec_connection_disconnect
dbDisconnect() returns TRUE, invisibly.
A warning is issued on garbage collection when a connection has been
released without calling dbDisconnect(),
but this cannot be tested automatically.
At least one warning is issued immediately when calling dbDisconnect() on an
already disconnected
or invalid connection.
Other connection specifications:
spec_get_info
spec_driver_connect
dbConnect() returns an S4 object that inherits from DBI::DBIConnection.
This object is used to communicate with the database engine.
A format() method is defined for the connection object.
It returns a string that consists of a single line of text.
DBI recommends using the following argument names for authentication
parameters, with NULL default:
user for the user name (default: current user)
password for the password
host for the host name (default: local connection)
port for the port number (default: local connection)
dbname for the name of the database on the host, or the database file
name
The defaults should provide reasonable behavior, in particular a
local connection for host = NULL. For some DBMS (e.g., PostgreSQL),
this is different to a TCP/IP connection to localhost.
In addition, DBI supports the bigint argument that governs how
64-bit integer data is returned. The following values are supported:
"integer": always return as integer, silently overflow
"numeric": always return as numeric, silently round
"character": always return the decimal representation as character
"integer64": return as a data type that can be coerced using
as.integer() (with warning on overflow), as.numeric()
and as.character()
Other driver specifications:
spec_driver_constructor,
spec_driver_data_type,
spec_get_info
spec_driver_constructor
The backend must support creation of an instance of its DBI::DBIDriver subclass
with a constructor function.
By default, its name is the package name without the leading ‘R’
(if it exists), e.g., SQLite for the RSQLite package.
However, backend authors may choose a different name.
The constructor must be exported, and
it must be a function
that is callable without arguments.
DBI recommends to define a constructor with an empty argument list.
Other driver specifications:
spec_driver_connect,
spec_driver_data_type,
spec_get_info
spec_driver_data_type
dbDataType() returns the SQL type that corresponds to the obj argument
as a non-empty
character string.
For data frames, a character vector with one element per column
is returned.
An error is raised for invalid values for the obj argument such as a
NULL value.
The backend can override the DBI::dbDataType() generic
for its driver class.
This generic expects an arbitrary object as second argument.
To query the values returned by the default implementation,
run example(dbDataType, package = "DBI").
If the backend needs to override this generic,
it must accept all basic R data types as its second argument, namely
logical,
integer,
numeric,
character,
dates (see Dates),
date-time (see DateTimeClasses),
and difftime.
If the database supports blobs,
this method also must accept lists of raw vectors,
and blob::blob objects.
As-is objects (i.e., wrapped by I()) must be
supported and return the same results as their unwrapped counterparts.
The SQL data type for factor and
ordered is the same as for character.
The behavior for other object types is not specified.
Other driver specifications:
spec_driver_connect,
spec_driver_constructor,
spec_get_info
spec_driver_get_info
spec_connection_get_info
spec_meta_get_info_result
For objects of class DBI::DBIDriver, dbGetInfo()
returns a named list
that contains at least the following components:
driver.version: the package version of the DBI backend,
client.version: the version of the DBMS client library.
For objects of class DBI::DBIConnection, dbGetInfo()
returns a named list
that contains at least the following components:
db.version: version of the database server,
dbname: database name,
username: username to connect to the database,
host: hostname of the database server,
port: port on the database server.
It must not contain a password component.
Components that are not applicable should be set to NA.
For objects of class DBI::DBIResult, dbGetInfo()
returns a named list
that contains at least the following components:
statatment: the statement used with DBI::dbSendQuery() or DBI::dbExecute(),
as returned by DBI::dbGetStatement(),
row.count: the number of rows fetched so far (for queries),
as returned by DBI::dbGetRowCount(),
rows.affected: the number of rows affected (for statements),
as returned by DBI::dbGetRowsAffected()
has.completed: a logical that indicates
if the query or statement has completed,
as returned by DBI::dbHasCompleted().
Other driver specifications:
spec_driver_connect,
spec_driver_constructor,
spec_driver_data_type
Other connection specifications:
spec_connection_disconnect
Other meta specifications:
spec_meta_bind,
spec_meta_column_info,
spec_meta_get_row_count,
spec_meta_get_rows_affected,
spec_meta_get_statement,
spec_meta_has_completed,
spec_meta_is_valid
spec_getting_started
A DBI backend is an R package which imports the DBI and methods packages. For better or worse, the names of many existing backends start with ‘R’, e.g., RSQLite, RMySQL, RSQLServer; it is up to the backend author to adopt this convention or not.
spec_meta_bind
spec_meta_bind
spec_meta_bind
dbBind() returns the result set,
invisibly,
for queries issued by DBI::dbSendQuery() or DBI::dbSendQueryArrow() and
also for data manipulation statements issued by
DBI::dbSendStatement().
DBI clients execute parametrized statements as follows:
Call DBI::dbSendQuery(), DBI::dbSendQueryArrow() or DBI::dbSendStatement()
with a query or statement that contains placeholders,
store the returned DBI::DBIResult object in a variable.
Mixing placeholders (in particular, named and unnamed ones) is not
recommended.
It is good practice to register a call to DBI::dbClearResult() via
on.exit() right after calling dbSendQuery() or dbSendStatement()
(see the last enumeration item).
Until DBI::dbBind() or DBI::dbBindArrow() have been called,
the returned result set object has the following behavior:
DBI::dbFetch() raises an error (for dbSendQuery() and dbSendQueryArrow())
DBI::dbGetRowCount() returns zero (for dbSendQuery() and dbSendQueryArrow())
DBI::dbGetRowsAffected() returns an integer NA (for dbSendStatement())
DBI::dbIsValid() returns TRUE
DBI::dbHasCompleted() returns FALSE
Call DBI::dbBind() or DBI::dbBindArrow():
For DBI::dbBind(), the params argument must be a list where all elements
have the same lengths and contain values supported by the backend.
A data.frame is internally stored as such a list.
For DBI::dbBindArrow(), the params argument must be a
nanoarrow array stream, with one column per query parameter.
Retrieve the data or the number of affected rows from the DBIResult object.
For queries issued by dbSendQuery() or dbSendQueryArrow(), call DBI::dbFetch().
For statements issued by dbSendStatements(),
call DBI::dbGetRowsAffected().
(Execution begins immediately after the DBI::dbBind() call,
the statement is processed entirely before the function returns.)
Repeat 2. and 3. as necessary.
Close the result set via DBI::dbClearResult().
The elements of the params argument do not need to be scalars,
vectors of arbitrary length
(including length 0)
are supported.
For queries, calling dbFetch() binding such parameters returns
concatenated results, equivalent to binding and fetching for each set
of values and connecting via rbind().
For data manipulation statements, dbGetRowsAffected() returns the
total number of rows affected if binding non-scalar parameters.
dbBind() also accepts repeated calls on the same result set
for both queries
and data manipulation statements,
even if no results are fetched between calls to dbBind(),
for both queries
and data manipulation statements.
If the placeholders in the query are named,
their order in the params argument is not important.
At least the following data types are accepted on input (including NA):
logical for Boolean values
character (also with special characters such as spaces, newlines, quotes, and backslashes)
factor (bound as character, with warning)
lubridate::Date (also when stored internally as integer)
lubridate::POSIXct timestamps
POSIXlt timestamps
difftime values (also with units other than seconds and with the value stored as integer)
lists of raw for blobs (with NULL entries for SQL NULL values)
objects of type blob::blob
Calling dbBind() for a query without parameters
raises an error.
Binding too many
or not enough values,
or parameters with wrong names
or unequal length,
also raises an error.
If the placeholders in the query are named,
all parameter values must have names
(which must not be empty
or NA),
and vice versa,
otherwise an error is raised.
The behavior for mixing placeholders of different types
(in particular mixing positional and named placeholders)
is not specified.
Calling dbBind() on a result set already cleared by DBI::dbClearResult()
also raises an error.
Other meta specifications:
spec_get_info,
spec_meta_column_info,
spec_meta_get_row_count,
spec_meta_get_rows_affected,
spec_meta_get_statement,
spec_meta_has_completed,
spec_meta_is_valid
Other meta specifications:
spec_get_info,
spec_meta_column_info,
spec_meta_get_row_count,
spec_meta_get_rows_affected,
spec_meta_get_statement,
spec_meta_has_completed,
spec_meta_is_valid
Other meta specifications:
spec_get_info,
spec_meta_column_info,
spec_meta_get_row_count,
spec_meta_get_rows_affected,
spec_meta_get_statement,
spec_meta_has_completed,
spec_meta_is_valid
spec_meta_column_info
dbColumnInfo()
returns a data frame
with at least two columns "name" and "type" (in that order)
(and optional columns that start with a dot).
The "name" and "type" columns contain the names and types
of the R columns of the data frame that is returned from DBI::dbFetch().
The "type" column is of type character and only for information.
Do not compute on the "type" column, instead use dbFetch(res, n = 0)
to create a zero-row data frame initialized with the correct data types.
An attempt to query columns for a closed result set raises an error.
A column named row_names is treated like any other column.
The column names are always consistent
with the data returned by dbFetch().
If the query returns unnamed columns,
non-empty and non-NA names are assigned.
Column names that correspond to SQL or R keywords are left unchanged.
Other meta specifications:
spec_get_info,
spec_meta_bind,
spec_meta_get_row_count,
spec_meta_get_rows_affected,
spec_meta_get_statement,
spec_meta_has_completed,
spec_meta_is_valid
spec_meta_get_row_count
dbGetRowCount() returns a scalar number (integer or numeric),
the number of rows fetched so far.
After calling DBI::dbSendQuery(),
the row count is initially zero.
After a call to DBI::dbFetch() without limit,
the row count matches the total number of rows returned.
Fetching a limited number of rows
increases the number of rows by the number of rows returned,
even if fetching past the end of the result set.
For queries with an empty result set,
zero is returned
even after fetching.
For data manipulation statements issued with
DBI::dbSendStatement(),
zero is returned before
and after calling dbFetch().
Attempting to get the row count for a result set cleared with
DBI::dbClearResult() gives an error.
Other meta specifications:
spec_get_info,
spec_meta_bind,
spec_meta_column_info,
spec_meta_get_rows_affected,
spec_meta_get_statement,
spec_meta_has_completed,
spec_meta_is_valid
spec_meta_get_rows_affected
dbGetRowsAffected() returns a scalar number (integer or numeric),
the number of rows affected by a data manipulation statement
issued with DBI::dbSendStatement().
The value is available directly after the call
and does not change after calling DBI::dbFetch().
NA_integer_ or NA_numeric_ are allowed if the number of rows affected is not known.
For queries issued with DBI::dbSendQuery(),
zero is returned before
and after the call to dbFetch().
NA values are not allowed.
Attempting to get the rows affected for a result set cleared with
DBI::dbClearResult() gives an error.
Other meta specifications:
spec_get_info,
spec_meta_bind,
spec_meta_column_info,
spec_meta_get_row_count,
spec_meta_get_statement,
spec_meta_has_completed,
spec_meta_is_valid
spec_meta_get_statement
dbGetStatement() returns a string, the query used in
either DBI::dbSendQuery() or
DBI::dbSendStatement().
Attempting to query the statement for a result set cleared with
DBI::dbClearResult() gives an error.
Other meta specifications:
spec_get_info,
spec_meta_bind,
spec_meta_column_info,
spec_meta_get_row_count,
spec_meta_get_rows_affected,
spec_meta_has_completed,
spec_meta_is_valid
spec_meta_has_completed
dbHasCompleted() returns a logical scalar.
For a query initiated by DBI::dbSendQuery() with non-empty result set,
dbHasCompleted() returns FALSE initially
and TRUE after calling DBI::dbFetch() without limit.
For a query initiated by DBI::dbSendStatement(),
dbHasCompleted() always returns TRUE.
Attempting to query completion status for a result set cleared with
DBI::dbClearResult() gives an error.
The completion status for a query is only guaranteed to be set to
FALSE after attempting to fetch past the end of the entire result.
Therefore, for a query with an empty result set,
the initial return value is unspecified,
but the result value is TRUE after trying to fetch only one row.
Similarly, for a query with a result set of length n,
the return value is unspecified after fetching n rows,
but the result value is TRUE after trying to fetch only one more
row.
Other meta specifications:
spec_get_info,
spec_meta_bind,
spec_meta_column_info,
spec_meta_get_row_count,
spec_meta_get_rows_affected,
spec_meta_get_statement,
spec_meta_is_valid
spec_meta_is_valid
dbIsValid() returns a logical scalar,
TRUE if the object specified by dbObj is valid,
FALSE otherwise.
A DBI::DBIConnection object is initially valid,
and becomes invalid after disconnecting with DBI::dbDisconnect().
For an invalid connection object (e.g., for some drivers if the object
is saved to a file and then restored), the method also returns FALSE.
A DBI::DBIResult object is valid after a call to DBI::dbSendQuery(),
and stays valid even after all rows have been fetched;
only clearing it with DBI::dbClearResult() invalidates it.
A DBI::DBIResult object is also valid after a call to DBI::dbSendStatement(),
and stays valid after querying the number of rows affected;
only clearing it with DBI::dbClearResult() invalidates it.
If the connection to the database system is dropped (e.g., due to
connectivity problems, server failure, etc.), dbIsValid() should return
FALSE. This is not tested automatically.
Other meta specifications:
spec_get_info,
spec_meta_bind,
spec_meta_column_info,
spec_meta_get_row_count,
spec_meta_get_rows_affected,
spec_meta_get_statement,
spec_meta_has_completed
spec_result_clear_result
dbClearResult() returns TRUE, invisibly, for result sets obtained from
dbSendQuery(),
dbSendStatement(),
or dbSendQueryArrow(),
An attempt to close an already closed result set issues a warning
for dbSendQuery(),
dbSendStatement(),
and dbSendQueryArrow(),
dbClearResult() frees all resources associated with retrieving
the result of a query or update operation.
The DBI backend can expect a call to dbClearResult() for each
DBI::dbSendQuery() or DBI::dbSendStatement() call.
Other result specifications:
spec_result_create_table_with_data_type,
spec_result_execute,
spec_result_fetch,
spec_result_get_query,
spec_result_roundtrip,
spec_result_send_query,
spec_result_send_statement
Other Arrow specifications:
spec_arrow_append_table_arrow,
spec_arrow_create_table_arrow,
spec_arrow_fetch_arrow,
spec_arrow_fetch_arrow_chunk,
spec_arrow_get_query_arrow,
spec_arrow_read_table_arrow,
spec_arrow_send_query_arrow,
spec_arrow_write_table_arrow
spec_result_create_table_with_data_type
All data types returned by dbDataType() are usable in an SQL statement
of the form
"CREATE TABLE test (a ...)".
Other result specifications:
spec_result_clear_result,
spec_result_execute,
spec_result_fetch,
spec_result_get_query,
spec_result_roundtrip,
spec_result_send_query,
spec_result_send_statement
spec_result_execute
dbExecute() always returns a
scalar
numeric
that specifies the number of rows affected
by the statement.
An error is raised when issuing a statement over a closed
or invalid connection,
if the syntax of the statement is invalid,
or if the statement is not a non-NA string.
The following arguments are not part of the dbExecute() generic
(to improve compatibility across backends)
but are part of the DBI specification:
params (default: NULL)
immediate (default: NULL)
They must be provided as named arguments. See the "Specification" sections for details on their usage.
The param argument allows passing query parameters, see DBI::dbBind() for details.
immediate argumentThe immediate argument supports distinguishing between "direct"
and "prepared" APIs offered by many database drivers.
Passing immediate = TRUE leads to immediate execution of the
query or statement, via the "direct" API (if supported by the driver).
The default NULL means that the backend should choose whatever API
makes the most sense for the database, and (if relevant) tries the
other API if the first attempt fails. A successful second attempt
should result in a message that suggests passing the correct
immediate argument.
Examples for possible behaviors:
DBI backend defaults to immediate = TRUE internally
A query without parameters is passed: query is executed
A query with parameters is passed:
params not given: rejected immediately by the database
because of a syntax error in the query, the backend tries
immediate = FALSE (and gives a message)
params given: query is executed using immediate = FALSE
DBI backend defaults to immediate = FALSE internally
A query without parameters is passed:
simple query: query is executed
"special" query (such as setting a config options): fails,
the backend tries immediate = TRUE (and gives a message)
A query with parameters is passed:
params not given: waiting for parameters via DBI::dbBind()
params given: query is executed
Other result specifications:
spec_result_clear_result,
spec_result_create_table_with_data_type,
spec_result_fetch,
spec_result_get_query,
spec_result_roundtrip,
spec_result_send_query,
spec_result_send_statement
spec_result_fetch
dbFetch() always returns a data.frame with
as many rows as records were fetched and as many
columns as fields in the result set,
even if the result is a single value
or has one
or zero rows.
Passing n = NA is supported and returns an arbitrary number of rows (at least one)
as specified by the driver, but at most the remaining rows in the result set.
An attempt to fetch from a closed result set raises an error.
If the n argument is not an atomic whole number
greater or equal to -1 or Inf, an error is raised,
but a subsequent call to dbFetch() with proper n argument succeeds.
Calling dbFetch() on a result set from a data manipulation query
created by DBI::dbSendStatement() can
be fetched and return an empty data frame, with a warning.
Fetching multi-row queries with one
or more columns by default returns the entire result.
Multi-row queries can also be fetched progressively
by passing a whole number (integer or
numeric)
as the n argument.
A value of Inf for the n argument is supported
and also returns the full result.
If more rows than available are fetched, the result is returned in full
without warning.
If fewer rows than requested are returned, further fetches will
return a data frame with zero rows.
If zero rows are fetched, the columns of the data frame are still fully
typed.
Fetching fewer rows than available is permitted,
no warning is issued when clearing the result set.
A column named row_names is treated like any other column.
Other result specifications:
spec_result_clear_result,
spec_result_create_table_with_data_type,
spec_result_execute,
spec_result_get_query,
spec_result_roundtrip,
spec_result_send_query,
spec_result_send_statement
spec_result_get_query
dbGetQuery() always returns a data.frame, with
as many rows as records were fetched and as many
columns as fields in the result set,
even if the result is a single value
or has one
or zero rows.
An error is raised when issuing a query over a closed
or invalid connection,
if the syntax of the query is invalid,
or if the query is not a non-NA string.
If the n argument is not an atomic whole number
greater or equal to -1 or Inf, an error is raised,
but a subsequent call to dbGetQuery() with proper n argument succeeds.
The following arguments are not part of the dbGetQuery() generic
(to improve compatibility across backends)
but are part of the DBI specification:
n (default: -1)
params (default: NULL)
immediate (default: NULL)
They must be provided as named arguments. See the "Specification" and "Value" sections for details on their usage.
A column named row_names is treated like any other column.
The n argument specifies the number of rows to be fetched.
If omitted, fetching multi-row queries with one
or more columns returns the entire result.
A value of Inf for the n argument is supported
and also returns the full result.
If more rows than available are fetched (by passing a too large value for
n), the result is returned in full without warning.
If zero rows are requested, the columns of the data frame are still fully
typed.
Fetching fewer rows than available is permitted,
no warning is issued.
The param argument allows passing query parameters, see DBI::dbBind() for details.
immediate argumentThe immediate argument supports distinguishing between "direct"
and "prepared" APIs offered by many database drivers.
Passing immediate = TRUE leads to immediate execution of the
query or statement, via the "direct" API (if supported by the driver).
The default NULL means that the backend should choose whatever API
makes the most sense for the database, and (if relevant) tries the
other API if the first attempt fails. A successful second attempt
should result in a message that suggests passing the correct
immediate argument.
Examples for possible behaviors:
DBI backend defaults to immediate = TRUE internally
A query without parameters is passed: query is executed
A query with parameters is passed:
params not given: rejected immediately by the database
because of a syntax error in the query, the backend tries
immediate = FALSE (and gives a message)
params given: query is executed using immediate = FALSE
DBI backend defaults to immediate = FALSE internally
A query without parameters is passed:
simple query: query is executed
"special" query (such as setting a config options): fails,
the backend tries immediate = TRUE (and gives a message)
A query with parameters is passed:
params not given: waiting for parameters via DBI::dbBind()
params given: query is executed
Other result specifications:
spec_result_clear_result,
spec_result_create_table_with_data_type,
spec_result_execute,
spec_result_fetch,
spec_result_roundtrip,
spec_result_send_query,
spec_result_send_statement
spec_result_roundtrip
The column types of the returned data frame depend on the data returned:
integer (or coercible to an integer) for integer values between -2^31 and 2^31 - 1,
with NA for SQL NULL values
numeric for numbers with a fractional component,
with NA for SQL NULL values
logical for Boolean values (some backends may return an integer);
with NA for SQL NULL values
character for text,
with NA for SQL NULL values
lists of raw for blobs with NULL entries for SQL NULL values
coercible using as.Date() for dates,
with NA for SQL NULL values
(also applies to the return value of the SQL function current_date)
coercible using hms::as_hms() for times,
with NA for SQL NULL values
(also applies to the return value of the SQL function current_time)
coercible using as.POSIXct() for timestamps,
with NA for SQL NULL values
(also applies to the return value of the SQL function current_timestamp)
If dates and timestamps are supported by the backend, the following R types are used:
lubridate::Date for dates
(also applies to the return value of the SQL function current_date)
lubridate::POSIXct for timestamps
(also applies to the return value of the SQL function current_timestamp)
R has no built-in type with lossless support for the full range of 64-bit or larger integers. If 64-bit integers are returned from a query, the following rules apply:
Values are returned in a container with support for the full range of
valid 64-bit values (such as the integer64 class of the bit64
package)
Coercion to numeric always returns a number that is as close as possible to the true value
Loss of precision when converting to numeric gives a warning
Conversion to character always returns a lossless decimal representation of the data
Other result specifications:
spec_result_clear_result,
spec_result_create_table_with_data_type,
spec_result_execute,
spec_result_fetch,
spec_result_get_query,
spec_result_send_query,
spec_result_send_statement
spec_result_send_query
dbSendQuery() returns
an S4 object that inherits from DBI::DBIResult.
The result set can be used with DBI::dbFetch() to extract records.
Once you have finished using a result, make sure to clear it
with DBI::dbClearResult().
An error is raised when issuing a query over a closed
or invalid connection,
or if the query is not a non-NA string.
An error is also raised if the syntax of the query is invalid
and all query parameters are given (by passing the params argument)
or the immediate argument is set to TRUE.
The following arguments are not part of the dbSendQuery() generic
(to improve compatibility across backends)
but are part of the DBI specification:
params (default: NULL)
immediate (default: NULL)
They must be provided as named arguments. See the "Specification" sections for details on their usage.
No warnings occur under normal conditions.
When done, the DBIResult object must be cleared with a call to
DBI::dbClearResult().
Failure to clear the result set leads to a warning
when the connection is closed.
If the backend supports only one open result set per connection,
issuing a second query invalidates an already open result set
and raises a warning.
The newly opened result set is valid
and must be cleared with dbClearResult().
The param argument allows passing query parameters, see DBI::dbBind() for details.
immediate argumentThe immediate argument supports distinguishing between "direct"
and "prepared" APIs offered by many database drivers.
Passing immediate = TRUE leads to immediate execution of the
query or statement, via the "direct" API (if supported by the driver).
The default NULL means that the backend should choose whatever API
makes the most sense for the database, and (if relevant) tries the
other API if the first attempt fails. A successful second attempt
should result in a message that suggests passing the correct
immediate argument.
Examples for possible behaviors:
DBI backend defaults to immediate = TRUE internally
A query without parameters is passed: query is executed
A query with parameters is passed:
params not given: rejected immediately by the database
because of a syntax error in the query, the backend tries
immediate = FALSE (and gives a message)
params given: query is executed using immediate = FALSE
DBI backend defaults to immediate = FALSE internally
A query without parameters is passed:
simple query: query is executed
"special" query (such as setting a config options): fails,
the backend tries immediate = TRUE (and gives a message)
A query with parameters is passed:
params not given: waiting for parameters via DBI::dbBind()
params given: query is executed
Other result specifications:
spec_result_clear_result,
spec_result_create_table_with_data_type,
spec_result_execute,
spec_result_fetch,
spec_result_get_query,
spec_result_roundtrip,
spec_result_send_statement
spec_result_send_statement
dbSendStatement() returns
an S4 object that inherits from DBI::DBIResult.
The result set can be used with DBI::dbGetRowsAffected() to
determine the number of rows affected by the query.
Once you have finished using a result, make sure to clear it
with DBI::dbClearResult().
An error is raised when issuing a statement over a closed
or invalid connection,
or if the statement is not a non-NA string.
An error is also raised if the syntax of the query is invalid
and all query parameters are given (by passing the params argument)
or the immediate argument is set to TRUE.
No warnings occur under normal conditions.
When done, the DBIResult object must be cleared with a call to
DBI::dbClearResult().
Failure to clear the result set leads to a warning
when the connection is closed.
If the backend supports only one open result set per connection,
issuing a second query invalidates an already open result set
and raises a warning.
The newly opened result set is valid
and must be cleared with dbClearResult().
The param argument allows passing query parameters, see DBI::dbBind() for details.
The following arguments are not part of the dbSendStatement() generic
(to improve compatibility across backends)
but are part of the DBI specification:
params (default: NULL)
immediate (default: NULL)
They must be provided as named arguments. See the "Specification" sections for details on their usage.
immediate argumentThe immediate argument supports distinguishing between "direct"
and "prepared" APIs offered by many database drivers.
Passing immediate = TRUE leads to immediate execution of the
query or statement, via the "direct" API (if supported by the driver).
The default NULL means that the backend should choose whatever API
makes the most sense for the database, and (if relevant) tries the
other API if the first attempt fails. A successful second attempt
should result in a message that suggests passing the correct
immediate argument.
Examples for possible behaviors:
DBI backend defaults to immediate = TRUE internally
A query without parameters is passed: query is executed
A query with parameters is passed:
params not given: rejected immediately by the database
because of a syntax error in the query, the backend tries
immediate = FALSE (and gives a message)
params given: query is executed using immediate = FALSE
DBI backend defaults to immediate = FALSE internally
A query without parameters is passed:
simple query: query is executed
"special" query (such as setting a config options): fails,
the backend tries immediate = TRUE (and gives a message)
A query with parameters is passed:
params not given: waiting for parameters via DBI::dbBind()
params given: query is executed
Other result specifications:
spec_result_clear_result,
spec_result_create_table_with_data_type,
spec_result_execute,
spec_result_fetch,
spec_result_get_query,
spec_result_roundtrip,
spec_result_send_query
spec_sql_append_table
dbAppendTable() returns a
scalar
numeric.
If the table does not exist,
or the new data in values is not a data frame or has different column names,
an error is raised; the remote table remains unchanged.
An error is raised when calling this method for a closed
or invalid connection.
An error is also raised
if name cannot be processed with DBI::dbQuoteIdentifier() or
if this results in a non-scalar.
Invalid values for the row.names argument
(non-scalars,
unsupported data types,
NA)
also raise an error.
Passing a value argument different to NULL to the row.names argument
(in particular TRUE,
NA,
and a string)
raises an error.
SQL keywords can be used freely in table names, column names, and data. Quotes, commas, spaces, and other special characters such as newlines and tabs, can also be used in the data, and, if the database supports non-syntactic identifiers, also for table names and column names.
The following data types must be supported at least,
and be read identically with DBI::dbReadTable():
integer
numeric
(the behavior for Inf and NaN is not specified)
logical
NA as NULL
64-bit values (using "bigint" as field type); the result can be
converted to a numeric, which may lose precision,
converted a character vector, which gives the full decimal representation
written to another table and read again unchanged
character (in both UTF-8 and native encodings), supporting empty strings (before and after non-empty strings)
factor (returned as character, with a warning)
list of raw (if supported by the database)
objects of type blob::blob (if supported by the database)
date
(if supported by the database;
returned as Date)
also for dates prior to 1970 or 1900 or after 2038
time
(if supported by the database;
returned as objects that inherit from difftime)
timestamp
(if supported by the database;
returned as POSIXct
respecting the time zone but not necessarily preserving the
input time zone),
also for timestamps prior to 1970 or 1900 or after 2038
respecting the time zone but not necessarily preserving the
input time zone)
Mixing column types in the same table is supported.
The name argument is processed as follows,
to support databases that allow non-syntactic names for their objects:
If an unquoted table name as string: dbAppendTable() will do the quoting,
perhaps by calling dbQuoteIdentifier(conn, x = name)
If the result of a call to DBI::dbQuoteIdentifier(): no more quoting is done
to support databases that allow non-syntactic names for their objects:
The row.names argument must be NULL, the default value.
Row names are ignored.
The value argument must be a data frame
with a subset of the columns of the existing table.
The order of the columns does not matter.
Other sql specifications:
spec_sql_create_table,
spec_sql_exists_table,
spec_sql_list_fields,
spec_sql_list_objects,
spec_sql_list_tables,
spec_sql_quote_identifier,
spec_sql_quote_literal,
spec_sql_quote_string,
spec_sql_read_table,
spec_sql_remove_table,
spec_sql_unquote_identifier,
spec_sql_write_table
spec_sql_create_table
dbCreateTable() returns TRUE, invisibly.
If the table exists, an error is raised; the remote table remains unchanged.
An error is raised when calling this method for a closed
or invalid connection.
An error is also raised
if name cannot be processed with DBI::dbQuoteIdentifier() or
if this results in a non-scalar.
Invalid values for the row.names and temporary arguments
(non-scalars,
unsupported data types,
NA,
incompatible values,
duplicate names)
also raise an error.
The following arguments are not part of the dbCreateTable() generic
(to improve compatibility across backends)
but are part of the DBI specification:
temporary (default: FALSE)
They must be provided as named arguments. See the "Specification" and "Value" sections for details on their usage.
The name argument is processed as follows,
to support databases that allow non-syntactic names for their objects:
If an unquoted table name as string: dbCreateTable() will do the quoting,
perhaps by calling dbQuoteIdentifier(conn, x = name)
If the result of a call to DBI::dbQuoteIdentifier(): no more quoting is done
The value argument can be:
a data frame,
a named list of SQL types
If the temporary argument is TRUE, the table is not available in a
second connection and is gone after reconnecting.
Not all backends support this argument.
A regular, non-temporary table is visible in a second connection,
in a pre-existing connection,
and after reconnecting to the database.
SQL keywords can be used freely in table names, column names, and data. Quotes, commas, and spaces can also be used for table names and column names, if the database supports non-syntactic identifiers.
The row.names argument must be missing
or NULL, the default value.
All other values for the row.names argument
(in particular TRUE,
NA,
and a string)
raise an error.
Other sql specifications:
spec_sql_append_table,
spec_sql_exists_table,
spec_sql_list_fields,
spec_sql_list_objects,
spec_sql_list_tables,
spec_sql_quote_identifier,
spec_sql_quote_literal,
spec_sql_quote_string,
spec_sql_read_table,
spec_sql_remove_table,
spec_sql_unquote_identifier,
spec_sql_write_table
spec_sql_exists_table
dbExistsTable() returns a logical scalar, TRUE if the table or view
specified by the name argument exists, FALSE otherwise.
This includes temporary tables if supported by the database.
An error is raised when calling this method for a closed
or invalid connection.
An error is also raised
if name cannot be processed with DBI::dbQuoteIdentifier() or
if this results in a non-scalar.
The name argument is processed as follows,
to support databases that allow non-syntactic names for their objects:
If an unquoted table name as string: dbExistsTable() will do the
quoting,
perhaps by calling dbQuoteIdentifier(conn, x = name)
If the result of a call to DBI::dbQuoteIdentifier(): no more quoting is done
For all tables listed by DBI::dbListTables(), dbExistsTable() returns TRUE.
Other sql specifications:
spec_sql_append_table,
spec_sql_create_table,
spec_sql_list_fields,
spec_sql_list_objects,
spec_sql_list_tables,
spec_sql_quote_identifier,
spec_sql_quote_literal,
spec_sql_quote_string,
spec_sql_read_table,
spec_sql_remove_table,
spec_sql_unquote_identifier,
spec_sql_write_table
spec_sql_list_fields
dbListFields()
returns a character vector
that enumerates all fields
in the table in the correct order.
This also works for temporary tables if supported by the database.
The returned names are suitable for quoting with dbQuoteIdentifier().
If the table does not exist, an error is raised.
Invalid types for the name argument
(e.g., character of length not equal to one,
or numeric)
lead to an error.
An error is also raised when calling this method for a closed
or invalid connection.
The name argument can be
a string
the return value of DBI::dbQuoteIdentifier()
a value from the table column from the return value of
DBI::dbListObjects() where is_prefix is FALSE
A column named row_names is treated like any other column.
Other sql specifications:
spec_sql_append_table,
spec_sql_create_table,
spec_sql_exists_table,
spec_sql_list_objects,
spec_sql_list_tables,
spec_sql_quote_identifier,
spec_sql_quote_literal,
spec_sql_quote_string,
spec_sql_read_table,
spec_sql_remove_table,
spec_sql_unquote_identifier,
spec_sql_write_table
spec_sql_list_objects
dbListObjects()
returns a data frame
with columns
table and is_prefix (in that order),
optionally with other columns with a dot (.) prefix.
The table column is of type list.
Each object in this list is suitable for use as argument in DBI::dbQuoteIdentifier().
The is_prefix column is a logical.
This data frame contains one row for each object (schema, table
and view)
accessible from the prefix (if passed) or from the global namespace
(if prefix is omitted).
Tables added with DBI::dbWriteTable() are
part of the data frame.
As soon a table is removed from the database,
it is also removed from the data frame of database objects.
The same applies to temporary objects if supported by the database.
The returned names are suitable for quoting with dbQuoteIdentifier().
An error is raised when calling this method for a closed or invalid connection.
The prefix column indicates if the table value refers to a table
or a prefix.
For a call with the default prefix = NULL, the table
values that have is_prefix == FALSE correspond to the tables
returned from DBI::dbListTables(),
The table object can be quoted with DBI::dbQuoteIdentifier().
The result of quoting can be passed to DBI::dbUnquoteIdentifier().
(For backends it may be convenient to use the DBI::Id class, but this is
not required.)
Values in table column that have is_prefix == TRUE can be
passed as the prefix argument to another call to dbListObjects().
For the data frame returned from a dbListObject() call with the
prefix argument set, all table values where is_prefix is
FALSE can be used in a call to DBI::dbExistsTable() which returns
TRUE.
Other sql specifications:
spec_sql_append_table,
spec_sql_create_table,
spec_sql_exists_table,
spec_sql_list_fields,
spec_sql_list_tables,
spec_sql_quote_identifier,
spec_sql_quote_literal,
spec_sql_quote_string,
spec_sql_read_table,
spec_sql_remove_table,
spec_sql_unquote_identifier,
spec_sql_write_table
spec_sql_list_tables
dbListTables()
returns a character vector
that enumerates all tables
and views
in the database.
Tables added with DBI::dbWriteTable() are
part of the list.
As soon a table is removed from the database,
it is also removed from the list of database tables.
The same applies to temporary tables if supported by the database.
The returned names are suitable for quoting with dbQuoteIdentifier().
An error is raised when calling this method for a closed or invalid connection.
Other sql specifications:
spec_sql_append_table,
spec_sql_create_table,
spec_sql_exists_table,
spec_sql_list_fields,
spec_sql_list_objects,
spec_sql_quote_identifier,
spec_sql_quote_literal,
spec_sql_quote_string,
spec_sql_read_table,
spec_sql_remove_table,
spec_sql_unquote_identifier,
spec_sql_write_table
spec_sql_quote_identifier
dbQuoteIdentifier() returns an object that can be coerced to character,
of the same length as the input.
For an empty character vector this function returns a length-0 object.
The names of the input argument are preserved in the output.
When passing the returned object again to dbQuoteIdentifier()
as x
argument, it is returned unchanged.
Passing objects of class DBI::SQL should also return them unchanged.
(For backends it may be most convenient to return DBI::SQL objects
to achieve this behavior, but this is not required.)
An error is raised if the input contains NA,
but not for an empty string.
Calling DBI::dbGetQuery() for a query of the format SELECT 1 AS ...
returns a data frame with the identifier, unquoted, as column name.
Quoted identifiers can be used as table and column names in SQL queries,
in particular in queries like SELECT 1 AS ...
and SELECT * FROM (SELECT 1) ....
The method must use a quoting mechanism that is unambiguously different
from the quoting mechanism used for strings, so that a query like
SELECT ... FROM (SELECT 1 AS ...)
throws an error if the column names do not match.
The method can quote column names that
contain special characters such as a space,
a dot,
a comma,
or quotes used to mark strings
or identifiers,
if the database supports this.
In any case, checking the validity of the identifier
should be performed only when executing a query,
and not by dbQuoteIdentifier().
Other sql specifications:
spec_sql_append_table,
spec_sql_create_table,
spec_sql_exists_table,
spec_sql_list_fields,
spec_sql_list_objects,
spec_sql_list_tables,
spec_sql_quote_literal,
spec_sql_quote_string,
spec_sql_read_table,
spec_sql_remove_table,
spec_sql_unquote_identifier,
spec_sql_write_table
spec_sql_quote_literal
dbQuoteLiteral() returns an object that can be coerced to character,
of the same length as the input.
For an empty
integer,
numeric,
character,
logical,
date,
time,
or blob vector,
this function returns a length-0 object.
When passing the returned object again to dbQuoteLiteral()
as x
argument, it is returned unchanged.
Passing objects of class DBI::SQL should also return them unchanged.
(For backends it may be most convenient to return DBI::SQL objects
to achieve this behavior, but this is not required.)
The returned expression can be used in a SELECT ... query,
and the value of
dbGetQuery(paste0("SELECT ", dbQuoteLiteral(x)))[[1]]
must be equal to x
for any scalar
integer,
numeric,
string,
and logical.
If x is NA, the result must merely satisfy is.na().
The literals "NA" or "NULL" are not treated specially.
NA should be translated to an unquoted SQL NULL,
so that the query SELECT * FROM (SELECT 1) a WHERE ... IS NULL
returns one row.
Passing a list
for the x argument raises an error.
Other sql specifications:
spec_sql_append_table,
spec_sql_create_table,
spec_sql_exists_table,
spec_sql_list_fields,
spec_sql_list_objects,
spec_sql_list_tables,
spec_sql_quote_identifier,
spec_sql_quote_string,
spec_sql_read_table,
spec_sql_remove_table,
spec_sql_unquote_identifier,
spec_sql_write_table
spec_sql_quote_string
dbQuoteString() returns an object that can be coerced to character,
of the same length as the input.
For an empty character vector this function returns a length-0 object.
When passing the returned object again to dbQuoteString()
as x
argument, it is returned unchanged.
Passing objects of class DBI::SQL should also return them unchanged.
(For backends it may be most convenient to return DBI::SQL objects
to achieve this behavior, but this is not required.)
The returned expression can be used in a SELECT ... query,
and for any scalar character x the value of
dbGetQuery(paste0("SELECT ", dbQuoteString(x)))[[1]]
must be identical to x,
even if x contains
spaces,
tabs,
quotes (single
or double),
backticks,
or newlines
(in any combination)
or is itself the result of a dbQuoteString() call coerced back to
character (even repeatedly).
If x is NA, the result must merely satisfy is.na().
The strings "NA" or "NULL" are not treated specially.
NA should be translated to an unquoted SQL NULL,
so that the query SELECT * FROM (SELECT 1) a WHERE ... IS NULL
returns one row.
Passing a numeric,
integer,
logical,
or raw vector,
or a list
for the x argument raises an error.
Other sql specifications:
spec_sql_append_table,
spec_sql_create_table,
spec_sql_exists_table,
spec_sql_list_fields,
spec_sql_list_objects,
spec_sql_list_tables,
spec_sql_quote_identifier,
spec_sql_quote_literal,
spec_sql_read_table,
spec_sql_remove_table,
spec_sql_unquote_identifier,
spec_sql_write_table
spec_sql_read_table
dbReadTable() returns a data frame that contains the complete data
from the remote table, effectively the result of calling DBI::dbGetQuery() with
SELECT * FROM <name>.
An empty table is returned as a data frame with zero rows.
The presence of rownames depends on the row.names argument,
see DBI::sqlColumnToRownames() for details:
If FALSE or NULL, the returned data frame doesn't have row names.
If TRUE, a column named "row_names" is converted to row names.
If NA, a column named "row_names" is converted to row names if it exists,
otherwise no translation occurs.
If a string, this specifies the name of the column in the remote table that contains the row names.
The default is row.names = FALSE.
If the database supports identifiers with special characters,
the columns in the returned data frame are converted to valid R
identifiers
if the check.names argument is TRUE,
If check.names = FALSE, the returned table has non-syntactic column names without quotes.
An error is raised if the table does not exist.
An error is raised if row.names is TRUE and no "row_names" column exists,
An error is raised if row.names is set to a string and no corresponding column exists.
An error is raised when calling this method for a closed
or invalid connection.
An error is raised
if name cannot be processed with DBI::dbQuoteIdentifier()
or if this results in a non-scalar.
Unsupported values for row.names and check.names
(non-scalars,
unsupported data types,
NA for check.names)
also raise an error.
The following arguments are not part of the dbReadTable() generic
(to improve compatibility across backends)
but are part of the DBI specification:
row.names (default: FALSE)
check.names
They must be provided as named arguments. See the "Value" section for details on their usage.
The name argument is processed as follows,
to support databases that allow non-syntactic names for their objects:
If an unquoted table name as string: dbReadTable() will do the
quoting,
perhaps by calling dbQuoteIdentifier(conn, x = name)
If the result of a call to DBI::dbQuoteIdentifier(): no more quoting is done
Other sql specifications:
spec_sql_append_table,
spec_sql_create_table,
spec_sql_exists_table,
spec_sql_list_fields,
spec_sql_list_objects,
spec_sql_list_tables,
spec_sql_quote_identifier,
spec_sql_quote_literal,
spec_sql_quote_string,
spec_sql_remove_table,
spec_sql_unquote_identifier,
spec_sql_write_table
spec_sql_remove_table
dbRemoveTable() returns TRUE, invisibly.
If the table does not exist, an error is raised. An attempt to remove a view with this function may result in an error.
An error is raised when calling this method for a closed
or invalid connection.
An error is also raised
if name cannot be processed with DBI::dbQuoteIdentifier() or
if this results in a non-scalar.
The following arguments are not part of the dbRemoveTable() generic
(to improve compatibility across backends)
but are part of the DBI specification:
temporary (default: FALSE)
fail_if_missing (default: TRUE)
These arguments must be provided as named arguments.
If temporary is TRUE, the call to dbRemoveTable()
will consider only temporary tables.
Not all backends support this argument.
In particular, permanent tables of the same name are left untouched.
If fail_if_missing is FALSE, the call to dbRemoveTable()
succeeds if the table does not exist.
A table removed by dbRemoveTable() doesn't appear in the list of tables
returned by DBI::dbListTables(),
and DBI::dbExistsTable() returns FALSE.
The removal propagates immediately to other connections to the same database.
This function can also be used to remove a temporary table.
The name argument is processed as follows,
to support databases that allow non-syntactic names for their objects:
If an unquoted table name as string: dbRemoveTable() will do the
quoting,
perhaps by calling dbQuoteIdentifier(conn, x = name)
If the result of a call to DBI::dbQuoteIdentifier(): no more quoting is done
Other sql specifications:
spec_sql_append_table,
spec_sql_create_table,
spec_sql_exists_table,
spec_sql_list_fields,
spec_sql_list_objects,
spec_sql_list_tables,
spec_sql_quote_identifier,
spec_sql_quote_literal,
spec_sql_quote_string,
spec_sql_read_table,
spec_sql_unquote_identifier,
spec_sql_write_table
spec_sql_unquote_identifier
dbUnquoteIdentifier() returns a list of objects
of the same length as the input.
For an empty vector, this function returns a length-0 object.
The names of the input argument are preserved in the output.
If x is a value returned by dbUnquoteIdentifier(),
calling dbUnquoteIdentifier(..., dbQuoteIdentifier(..., x))
returns list(x).
If x is an object of class DBI::Id,
calling dbUnquoteIdentifier(..., x) returns list(x).
(For backends it may be most convenient to return DBI::Id objects
to achieve this behavior, but this is not required.)
Plain character vectors can also be passed to dbUnquoteIdentifier().
An error is raised if a character vectors with a missing value is passed
as the x argument.
For any character vector of length one, quoting (with DBI::dbQuoteIdentifier())
then unquoting then quoting the first element is identical to just quoting.
This is also true for strings that
contain special characters such as a space,
a dot,
a comma,
or quotes used to mark strings
or identifiers,
if the database supports this.
Unquoting simple strings (consisting of only letters) wrapped with DBI::SQL() and
then quoting via DBI::dbQuoteIdentifier() gives the same result as just
quoting the string.
Similarly, unquoting expressions of the form SQL("schema.table")
and then quoting gives the same result as quoting the identifier
constructed by Id("schema", "table").
Other sql specifications:
spec_sql_append_table,
spec_sql_create_table,
spec_sql_exists_table,
spec_sql_list_fields,
spec_sql_list_objects,
spec_sql_list_tables,
spec_sql_quote_identifier,
spec_sql_quote_literal,
spec_sql_quote_string,
spec_sql_read_table,
spec_sql_remove_table,
spec_sql_write_table
spec_sql_write_table
dbWriteTable() returns TRUE, invisibly.
If the table exists, and both append and overwrite arguments are unset,
or append = TRUE and the data frame with the new data has different
column names,
an error is raised; the remote table remains unchanged.
An error is raised when calling this method for a closed
or invalid connection.
An error is also raised
if name cannot be processed with DBI::dbQuoteIdentifier() or
if this results in a non-scalar.
Invalid values for the additional arguments row.names,
overwrite, append, field.types, and temporary
(non-scalars,
unsupported data types,
NA,
incompatible values,
duplicate
or missing names,
incompatible columns)
also raise an error.
The following arguments are not part of the dbWriteTable() generic
(to improve compatibility across backends)
but are part of the DBI specification:
row.names (default: FALSE)
overwrite (default: FALSE)
append (default: FALSE)
field.types (default: NULL)
temporary (default: FALSE)
They must be provided as named arguments. See the "Specification" and "Value" sections for details on their usage.
The name argument is processed as follows,
to support databases that allow non-syntactic names for their objects:
If an unquoted table name as string: dbWriteTable() will do the quoting,
perhaps by calling dbQuoteIdentifier(conn, x = name)
If the result of a call to DBI::dbQuoteIdentifier(): no more quoting is done
The value argument must be a data frame
with a subset of the columns of the existing table if append = TRUE.
The order of the columns does not matter with append = TRUE.
If the overwrite argument is TRUE, an existing table of the same name
will be overwritten.
This argument doesn't change behavior if the table does not exist yet.
If the append argument is TRUE, the rows in an existing table are
preserved, and the new data are appended.
If the table doesn't exist yet, it is created.
If the temporary argument is TRUE, the table is not available in a
second connection and is gone after reconnecting.
Not all backends support this argument.
A regular, non-temporary table is visible in a second connection,
in a pre-existing connection,
and after reconnecting to the database.
SQL keywords can be used freely in table names, column names, and data. Quotes, commas, spaces, and other special characters such as newlines and tabs, can also be used in the data, and, if the database supports non-syntactic identifiers, also for table names and column names.
The following data types must be supported at least,
and be read identically with DBI::dbReadTable():
integer
numeric
(the behavior for Inf and NaN is not specified)
logical
NA as NULL
64-bit values (using "bigint" as field type); the result can be
converted to a numeric, which may lose precision,
converted a character vector, which gives the full decimal representation
written to another table and read again unchanged
character (in both UTF-8 and native encodings), supporting empty strings before and after a non-empty string
factor (returned as character)
list of raw (if supported by the database)
objects of type blob::blob (if supported by the database)
date
(if supported by the database;
returned as Date),
also for dates prior to 1970 or 1900 or after 2038
time
(if supported by the database;
returned as objects that inherit from difftime)
timestamp
(if supported by the database;
returned as POSIXct
respecting the time zone but not necessarily preserving the
input time zone),
also for timestamps prior to 1970 or 1900 or after 2038
respecting the time zone but not necessarily preserving the
input time zone)
Mixing column types in the same table is supported.
The field.types argument must be a named character vector with at most
one entry for each column.
It indicates the SQL data type to be used for a new column.
If a column is missed from field.types, the type is inferred
from the input data with DBI::dbDataType().
The interpretation of rownames depends on the row.names argument,
see DBI::sqlRownamesToColumn() for details:
If FALSE or NULL, row names are ignored.
If TRUE, row names are converted to a column named "row_names",
even if the input data frame only has natural row names from 1 to nrow(...).
If NA, a column named "row_names" is created if the data has custom row names,
no extra column is created in the case of natural row names.
If a string, this specifies the name of the column in the remote table that contains the row names, even if the input data frame only has natural row names.
The default is row.names = FALSE.
Other sql specifications:
spec_sql_append_table,
spec_sql_create_table,
spec_sql_exists_table,
spec_sql_list_fields,
spec_sql_list_objects,
spec_sql_list_tables,
spec_sql_quote_identifier,
spec_sql_quote_literal,
spec_sql_quote_string,
spec_sql_read_table,
spec_sql_remove_table,
spec_sql_unquote_identifier
spec_transaction_begin_commit_rollback
dbBegin(), dbCommit() and dbRollback() return TRUE, invisibly.
The implementations are expected to raise an error in case of failure,
but this is not tested.
In any way, all generics throw an error with a closed
or invalid connection.
In addition, a call to dbCommit()
or dbRollback()
without a prior call to dbBegin() raises an error.
Nested transactions are not supported by DBI,
an attempt to call dbBegin() twice
yields an error.
Actual support for transactions may vary between backends.
A transaction is initiated by a call to dbBegin()
and committed by a call to dbCommit().
Data written in a transaction must persist after the transaction is committed.
For example, a record that is missing when the transaction is started
but is created during the transaction
must exist
both during
and after the transaction,
and also in a new connection.
A transaction
can also be aborted with dbRollback().
All data written in such a transaction must be removed after the
transaction is rolled back.
For example, a record that is missing when the transaction is started
but is created during the transaction
must not exist anymore after the rollback.
Disconnection from a connection with an open transaction effectively rolls back the transaction. All data written in such a transaction must be removed after the transaction is rolled back.
The behavior is not specified if other arguments are passed to these
functions. In particular, RSQLite issues named transactions
with support for nesting
if the name argument is set.
The transaction isolation level is not specified by DBI.
Other transaction specifications:
spec_transaction_with_transaction
spec_transaction_with_transaction
dbWithTransaction() returns the value of the executed code.
Failure to initiate the transaction
(e.g., if the connection is closed
or invalid
of if DBI::dbBegin() has been called already)
gives an error.
dbWithTransaction() initiates a transaction with dbBegin(), executes
the code given in the code argument, and commits the transaction with
DBI::dbCommit().
If the code raises an error, the transaction is instead aborted with
DBI::dbRollback(), and the error is propagated.
If the code calls dbBreak(), execution of the code stops and the
transaction is silently aborted.
All side effects caused by the code
(such as the creation of new variables)
propagate to the calling environment.
Other transaction specifications:
spec_transaction_begin_commit_rollback
test_all() calls all tests defined in this package (see the section
"Tests" below). This function supports running only one test by setting an
environment variable, e.g., set the DBITEST_ONLY_RESULT to a nonempty
value to run only test_result().
test_some() allows testing one or more tests.
test_all(skip = NULL, run_only = NULL, ctx = get_default_context()) test_some(test, ctx = get_default_context())test_all(skip = NULL, run_only = NULL, ctx = get_default_context()) test_some(test, ctx = get_default_context())
skip |
|
run_only |
|
ctx |
|
test |
|
Internally ^ and $ are used as prefix and suffix around the
regular expressions passed in the skip and run_only arguments.
This function runs the following tests, except the stress tests:
test_getting_started():
Getting started with testing
test_driver():
Test the "Driver" class
test_connection():
Test the "Connection" class
test_result():
Test the "Result" class
test_sql():
Test SQL methods
test_meta():
Test metadata functions
test_transaction():
Test transaction functions
test_arrow():
Test Arrow methods
test_compliance():
Test full compliance to DBI
test_stress():
Stress tests (not tested with test_all)
Test Arrow methods
test_arrow(skip = NULL, run_only = NULL, ctx = get_default_context())test_arrow(skip = NULL, run_only = NULL, ctx = get_default_context())
skip |
|
run_only |
|
ctx |
|
Other tests:
test_compliance(),
test_connection(),
test_driver(),
test_getting_started(),
test_meta(),
test_result(),
test_sql(),
test_stress(),
test_transaction()
Test full compliance to DBI
test_compliance(skip = NULL, run_only = NULL, ctx = get_default_context())test_compliance(skip = NULL, run_only = NULL, ctx = get_default_context())
skip |
|
run_only |
|
ctx |
|
Other tests:
test_arrow(),
test_connection(),
test_driver(),
test_getting_started(),
test_meta(),
test_result(),
test_sql(),
test_stress(),
test_transaction()
Test the "Connection" class
test_connection(skip = NULL, run_only = NULL, ctx = get_default_context())test_connection(skip = NULL, run_only = NULL, ctx = get_default_context())
skip |
|
run_only |
|
ctx |
|
Other tests:
test_arrow(),
test_compliance(),
test_driver(),
test_getting_started(),
test_meta(),
test_result(),
test_sql(),
test_stress(),
test_transaction()
Test the "Driver" class
test_driver(skip = NULL, run_only = NULL, ctx = get_default_context())test_driver(skip = NULL, run_only = NULL, ctx = get_default_context())
skip |
|
run_only |
|
ctx |
|
Other tests:
test_arrow(),
test_compliance(),
test_connection(),
test_getting_started(),
test_meta(),
test_result(),
test_sql(),
test_stress(),
test_transaction()
Tests very basic features of a DBI driver package, to support testing and test-first development right from the start.
test_getting_started(skip = NULL, run_only = NULL, ctx = get_default_context())test_getting_started(skip = NULL, run_only = NULL, ctx = get_default_context())
skip |
|
run_only |
|
ctx |
|
Other tests:
test_arrow(),
test_compliance(),
test_connection(),
test_driver(),
test_meta(),
test_result(),
test_sql(),
test_stress(),
test_transaction()
Test metadata functions
test_meta(skip = NULL, run_only = NULL, ctx = get_default_context())test_meta(skip = NULL, run_only = NULL, ctx = get_default_context())
skip |
|
run_only |
|
ctx |
|
Other tests:
test_arrow(),
test_compliance(),
test_connection(),
test_driver(),
test_getting_started(),
test_result(),
test_sql(),
test_stress(),
test_transaction()
Test the "Result" class
test_result(skip = NULL, run_only = NULL, ctx = get_default_context())test_result(skip = NULL, run_only = NULL, ctx = get_default_context())
skip |
|
run_only |
|
ctx |
|
Other tests:
test_arrow(),
test_compliance(),
test_connection(),
test_driver(),
test_getting_started(),
test_meta(),
test_sql(),
test_stress(),
test_transaction()
Test SQL methods
test_sql(skip = NULL, run_only = NULL, ctx = get_default_context())test_sql(skip = NULL, run_only = NULL, ctx = get_default_context())
skip |
|
run_only |
|
ctx |
|
Other tests:
test_arrow(),
test_compliance(),
test_connection(),
test_driver(),
test_getting_started(),
test_meta(),
test_result(),
test_stress(),
test_transaction()
Test transaction functions
test_transaction(skip = NULL, run_only = NULL, ctx = get_default_context())test_transaction(skip = NULL, run_only = NULL, ctx = get_default_context())
skip |
|
run_only |
|
ctx |
|
Other tests:
test_arrow(),
test_compliance(),
test_connection(),
test_driver(),
test_getting_started(),
test_meta(),
test_result(),
test_sql(),
test_stress()
The tweaks are a way to control the behavior of certain tests. Currently,
you need to search the DBItest source code to understand which tests
are affected by which tweaks. This function is usually called to set the
tweaks argument in a make_context() call.
tweaks( ..., constructor_name = NULL, constructor_relax_args = FALSE, strict_identifier = FALSE, omit_blob_tests = FALSE, current_needs_parens = FALSE, union = function(x) paste(x, collapse = " UNION "), placeholder_pattern = NULL, logical_return = identity, date_cast = function(x) paste0("date('", x, "')"), time_cast = function(x) paste0("time('", x, "')"), timestamp_cast = function(x) paste0("timestamp('", x, "')"), blob_cast = identity, date_typed = TRUE, time_typed = TRUE, timestamp_typed = TRUE, temporary_tables = TRUE, list_temporary_tables = TRUE, allow_na_rows_affected = FALSE, is_null_check = function(x) paste0("(", x, " IS NULL)"), create_table_as = function(table_name, query) paste0("CREATE TABLE ", table_name, " AS ", query), dbitest_version = "1.7.1" )tweaks( ..., constructor_name = NULL, constructor_relax_args = FALSE, strict_identifier = FALSE, omit_blob_tests = FALSE, current_needs_parens = FALSE, union = function(x) paste(x, collapse = " UNION "), placeholder_pattern = NULL, logical_return = identity, date_cast = function(x) paste0("date('", x, "')"), time_cast = function(x) paste0("time('", x, "')"), timestamp_cast = function(x) paste0("timestamp('", x, "')"), blob_cast = identity, date_typed = TRUE, time_typed = TRUE, timestamp_typed = TRUE, temporary_tables = TRUE, list_temporary_tables = TRUE, allow_na_rows_affected = FALSE, is_null_check = function(x) paste0("(", x, " IS NULL)"), create_table_as = function(table_name, query) paste0("CREATE TABLE ", table_name, " AS ", query), dbitest_version = "1.7.1" )
... |
|
constructor_name |
|
constructor_relax_args |
|
strict_identifier |
|
omit_blob_tests |
|
current_needs_parens |
|
union |
|
placeholder_pattern |
|
logical_return |
|
date_cast |
|
time_cast |
|
timestamp_cast |
|
blob_cast |
|
date_typed |
|
time_typed |
|
timestamp_typed |
|
temporary_tables |
|
list_temporary_tables |
|
allow_na_rows_affected |
|
is_null_check |
|
create_table_as |
|
dbitest_version |
|
## Not run: make_context(..., tweaks = tweaks(strict_identifier = TRUE)) ## End(Not run)## Not run: make_context(..., tweaks = tweaks(strict_identifier = TRUE)) ## End(Not run)