django.db.backends.postgresql.operations.DatabaseOperations

class documentation

class DatabaseOperations(BaseDatabaseOperations):

Known subclasses: django.contrib.gis.db.backends.postgis.operations.PostGISOperations

Undocumented

Method	`_convert_field_to_tz`	Undocumented
Method	`_prepare_tzname_delta`	Undocumented
Method	`adapt_datefield_value`	Transform a date value to an object compatible with what is expected by the backend driver for date columns.
Method	`adapt_datetimefield_value`	Transform a datetime value to an object compatible with what is expected by the backend driver for datetime columns.
Method	`adapt_decimalfield_value`	Transform a decimal.Decimal value to an object compatible with what is expected by the backend driver for decimal (numeric) columns.
Method	`adapt_ipaddressfield_value`	Transform a string representation of an IP address into the expected type for the backend driver.
Method	`adapt_timefield_value`	Transform a time value to an object compatible with what is expected by the backend driver for time columns.
Method	`bulk_insert_sql`	Undocumented
Method	`date_extract_sql`	Given a lookup_type of 'year', 'month', or 'day', return the SQL that extracts a value from the given date field field_name.
Method	`date_trunc_sql`	Given a lookup_type of 'year', 'month', or 'day', return the SQL that truncates the given date or datetime field field_name to a date object with only the given specificity.
Method	`datetime_cast_date_sql`	Return the SQL to cast a datetime value to date value.
Method	`datetime_cast_time_sql`	Return the SQL to cast a datetime value to time value.
Method	`datetime_extract_sql`	Given a lookup_type of 'year', 'month', 'day', 'hour', 'minute', or 'second', return the SQL that extracts a value from the given datetime field field_name.
Method	`datetime_trunc_sql`	Given a lookup_type of 'year', 'month', 'day', 'hour', 'minute', or 'second', return the SQL that truncates the given datetime field field_name to a datetime object with only the given specificity.
Method	`deferrable_sql`	Return the SQL to make a constraint "initially deferred" during a CREATE TABLE statement.
Method	`distinct_sql`	Return an SQL DISTINCT clause which removes duplicate rows from the result set. If any fields are given, only check the given fields for duplicates.
Method	`explain_query_prefix`	Undocumented
Method	`fetch_returned_insert_rows`	Given a cursor object that has just performed an INSERT...RETURNING statement into a table, return the tuple of returned data.
Method	`ignore_conflicts_suffix_sql`	Undocumented
Method	`last_executed_query`	Return a string of the query last executed by the given cursor, with placeholders replaced with actual values.
Method	`lookup_cast`	Return the string to use in a query when performing lookups ("contains", "like", etc.). It should contain a '%s' placeholder for the column being searched against.
Method	`max_name_length`	Return the maximum length of an identifier.
Method	`no_limit_value`	Return the value to use for the LIMIT when we are wanting "LIMIT infinity". Return None if the limit clause can be omitted in this case.
Method	`prep_for_iexact_query`	Undocumented
Method	`prepare_sql_script`	Take an SQL script that may contain multiple lines and return a list of statements to feed to successive cursor.execute() calls.
Method	`quote_name`	Return a quoted version of the given table, index, or column name. Do not quote the given name if it's already been quoted.
Method	`return_insert_columns`	For backends that support returning columns as part of an insert query, return the SQL and params to append to the INSERT query. The returned fragment should contain a format string to hold the appropriate column.
Method	`sequence_reset_by_name_sql`	Return a list of the SQL statements required to reset sequences passed in `sequences`.
Method	`sequence_reset_sql`	Return a list of the SQL statements required to reset sequences for the given models.
Method	`set_time_zone_sql`	Return the SQL that will set the connection's time zone.
Method	`sql_flush`	Return a list of SQL statements required to remove all data from the given database tables (without actually removing the tables themselves).
Method	`subtract_temporals`	Undocumented
Method	`tablespace_sql`	Return the SQL that will be used in a query to define the tablespace.
Method	`time_trunc_sql`	Given a lookup_type of 'hour', 'minute' or 'second', return the SQL that truncates the given time or datetime field field_name to a time object with only the given specificity.
Method	`unification_cast_sql`	Given a field instance, return the SQL that casts the result of a union to that type. The resulting string should contain a '%s' placeholder for the expression being cast.
Class Variable	`cast_char_field_without_max_length`	Undocumented
Class Variable	`cast_data_types`	Undocumented
Class Variable	`explain_prefix`	Undocumented

Inherited from BaseDatabaseOperations:

Constant	`CURRENT_ROW`	Undocumented
Constant	`FOLLOWING`	Undocumented
Constant	`PRECEDING`	Undocumented
Constant	`UNBOUNDED_FOLLOWING`	Undocumented
Constant	`UNBOUNDED_PRECEDING`	Undocumented
Method	`__init__`	Undocumented
Method	`_get_limit_offset_params`	Undocumented
Method	`adapt_unknown_value`	Transform a value to something compatible with the backend driver.
Method	`autoinc_sql`	Return any SQL needed to support auto-incrementing primary keys, or None if no SQL is necessary.
Method	`binary_placeholder_sql`	Some backends require special syntax to insert binary content (MySQL for example uses '_binary %s').
Method	`bulk_batch_size`	Return the maximum allowed batch size for the backend. The fields are the fields going to be inserted in the batch, the objs contains all the objects to be inserted.
Method	`cache_key_culling_sql`	Return an SQL query that retrieves the first cache key greater than the n smallest.
Method	`check_expression_support`	Check that the backend supports the provided expression.
Method	`combine_duration_expression`	Undocumented
Method	`combine_expression`	No summary
Method	`compiler`	Return the SQLCompiler class corresponding to the given name, in the namespace corresponding to the `compiler_module` attribute on this backend.
Method	`conditional_expression_supported_in_where_clause`	Return True, if the conditional expression is supported in the WHERE clause.
Method	`convert_durationfield_value`	Undocumented
Method	`end_transaction_sql`	Return the SQL statement required to end a transaction.
Method	`execute_sql_flush`	Execute a list of SQL statements to flush the database.
Method	`fetch_returned_insert_columns`	Given a cursor object that has just performed an INSERT...RETURNING statement into a table, return the newly created data.
Method	`field_cast_sql`	No summary
Method	`for_update_sql`	Return the FOR UPDATE SQL clause to lock rows for an update operation.
Method	`force_no_ordering`	Return a list used in the "ORDER BY" clause to force no ordering at all. Return an empty list to include nothing in the ordering.
Method	`get_db_converters`	Return a list of functions needed to convert field data.
Method	`insert_statement`	Undocumented
Method	`integer_field_range`	Given an integer field internal type (e.g. 'PositiveIntegerField'), return a tuple of the (min_value, max_value) form representing the range of the column type bound to the field.
Method	`last_insert_id`	Given a cursor object that has just performed an INSERT statement into a table that has an auto-incrementing ID, return the newly created ID.
Method	`limit_offset_sql`	Return LIMIT/OFFSET SQL clause.
Method	`max_in_list_size`	Return the maximum number of items that can be passed in a single 'IN' list condition, or None if the backend does not impose a limit.
Method	`modify_insert_params`	Allow modification of insert parameters. Needed for Oracle Spatial backend due to #10888.
Method	`pk_default_value`	Return the value to use during an INSERT statement to specify that the field should use its default value.
Method	`prep_for_like_query`	Prepare a value for use in a LIKE query.
Method	`process_clob`	Return the value of a CLOB column, for backends that return a locator object that requires additional processing.
Method	`regex_lookup`	Return the string to use in a query when performing regular expression lookups (using "regex" or "iregex"). It should contain a '%s' placeholder for the column being searched against.
Method	`savepoint_commit_sql`	Return the SQL for committing the given savepoint.
Method	`savepoint_create_sql`	Return the SQL for starting a new savepoint. Only required if the "uses_savepoints" feature is True. The "sid" parameter is a string for the savepoint id.
Method	`savepoint_rollback_sql`	Return the SQL for rolling back the given savepoint.
Method	`start_transaction_sql`	Return the SQL statement required to start a transaction.
Method	`time_extract_sql`	Given a lookup_type of 'hour', 'minute', or 'second', return the SQL that extracts a value from the given time field field_name.
Method	`validate_autopk_value`	Certain backends do not accept some values for "serial" fields (for example zero in MySQL). Raise a ValueError if the value is invalid, otherwise return the validated value.
Method	`window_frame_end`	Undocumented
Method	`window_frame_range_start_end`	Undocumented
Method	`window_frame_rows_start_end`	Return SQL for start and end points in an OVER clause window frame.
Method	`window_frame_start`	Undocumented
Method	`year_lookup_bounds_for_date_field`	Return a two-elements list with the lower and upper bound to be used with a BETWEEN operator to query a DateField value using a year lookup.
Method	`year_lookup_bounds_for_datetime_field`	Return a two-elements list with the lower and upper bound to be used with a BETWEEN operator to query a DateTimeField value using a year lookup.
Class Variable	`compiler_module`	Undocumented
Class Variable	`integer_field_ranges`	Undocumented
Class Variable	`set_operators`	Undocumented
Instance Variable	`_cache`	Undocumented
Instance Variable	`connection`	Undocumented

def _convert_field_to_tz(self, field_name, tzname):

Undocumented

def _prepare_tzname_delta(self, tzname):

Undocumented

def adapt_datefield_value(self, value):

overrides django.db.backends.base.operations.BaseDatabaseOperations.adapt_datefield_value

Transform a date value to an object compatible with what is expected by the backend driver for date columns.

def adapt_datetimefield_value(self, value):

overrides django.db.backends.base.operations.BaseDatabaseOperations.adapt_datetimefield_value

Transform a datetime value to an object compatible with what is expected by the backend driver for datetime columns.

def adapt_decimalfield_value(self, value, max_digits=None, decimal_places=None):

overrides django.db.backends.base.operations.BaseDatabaseOperations.adapt_decimalfield_value

Transform a decimal.Decimal value to an object compatible with what is expected by the backend driver for decimal (numeric) columns.

def adapt_ipaddressfield_value(self, value):

overrides django.db.backends.base.operations.BaseDatabaseOperations.adapt_ipaddressfield_value

Transform a string representation of an IP address into the expected type for the backend driver.

def adapt_timefield_value(self, value):

overrides django.db.backends.base.operations.BaseDatabaseOperations.adapt_timefield_value

Transform a time value to an object compatible with what is expected by the backend driver for time columns.

def bulk_insert_sql(self, fields, placeholder_rows):

Undocumented

def date_extract_sql(self, lookup_type, field_name):

overrides django.db.backends.base.operations.BaseDatabaseOperations.date_extract_sql

Given a lookup_type of 'year', 'month', or 'day', return the SQL that extracts a value from the given date field field_name.

def date_trunc_sql(self, lookup_type, field_name, tzname=None):

overrides django.db.backends.base.operations.BaseDatabaseOperations.date_trunc_sql

Given a lookup_type of 'year', 'month', or 'day', return the SQL that truncates the given date or datetime field field_name to a date object with only the given specificity.

If tzname is provided, the given value is truncated in a specific timezone.

def datetime_cast_date_sql(self, field_name, tzname):

overrides django.db.backends.base.operations.BaseDatabaseOperations.datetime_cast_date_sql

Return the SQL to cast a datetime value to date value.

def datetime_cast_time_sql(self, field_name, tzname):

overrides django.db.backends.base.operations.BaseDatabaseOperations.datetime_cast_time_sql

Return the SQL to cast a datetime value to time value.

def datetime_extract_sql(self, lookup_type, field_name, tzname):

overrides django.db.backends.base.operations.BaseDatabaseOperations.datetime_extract_sql

Given a lookup_type of 'year', 'month', 'day', 'hour', 'minute', or 'second', return the SQL that extracts a value from the given datetime field field_name.

def datetime_trunc_sql(self, lookup_type, field_name, tzname):

overrides django.db.backends.base.operations.BaseDatabaseOperations.datetime_trunc_sql

Given a lookup_type of 'year', 'month', 'day', 'hour', 'minute', or 'second', return the SQL that truncates the given datetime field field_name to a datetime object with only the given specificity.

def deferrable_sql(self):

overrides django.db.backends.base.operations.BaseDatabaseOperations.deferrable_sql

Return the SQL to make a constraint "initially deferred" during a CREATE TABLE statement.

def distinct_sql(self, fields, params):

overrides django.db.backends.base.operations.BaseDatabaseOperations.distinct_sql

Return an SQL DISTINCT clause which removes duplicate rows from the result set. If any fields are given, only check the given fields for duplicates.

def explain_query_prefix(self, format=None, **options):

overrides django.db.backends.base.operations.BaseDatabaseOperations.explain_query_prefix

Undocumented

def fetch_returned_insert_rows(self, cursor):

Given a cursor object that has just performed an INSERT...RETURNING statement into a table, return the tuple of returned data.

def ignore_conflicts_suffix_sql(self, ignore_conflicts=None):

overrides django.db.backends.base.operations.BaseDatabaseOperations.ignore_conflicts_suffix_sql

Undocumented

def last_executed_query(self, cursor, sql, params):

overrides django.db.backends.base.operations.BaseDatabaseOperations.last_executed_query

Return a string of the query last executed by the given cursor, with placeholders replaced with actual values.

sql is the raw query containing placeholders and params is the sequence of parameters. These are used by default, but this method exists for database backends to provide a better implementation according to their own quoting schemes.

def lookup_cast(self, lookup_type, internal_type=None):

overrides django.db.backends.base.operations.BaseDatabaseOperations.lookup_cast

Return the string to use in a query when performing lookups ("contains", "like", etc.). It should contain a '%s' placeholder for the column being searched against.

def max_name_length(self):

overrides django.db.backends.base.operations.BaseDatabaseOperations.max_name_length

Return the maximum length of an identifier.

The maximum length of an identifier is 63 by default, but can be changed by recompiling PostgreSQL after editing the NAMEDATALEN macro in src/include/pg_config_manual.h.

This implementation returns 63, but can be overridden by a custom database backend that inherits most of its behavior from this one.

def no_limit_value(self):

overrides django.db.backends.base.operations.BaseDatabaseOperations.no_limit_value

Return the value to use for the LIMIT when we are wanting "LIMIT infinity". Return None if the limit clause can be omitted in this case.

def prep_for_iexact_query(self, x):

Undocumented

def prepare_sql_script(self, sql):

overrides django.db.backends.base.operations.BaseDatabaseOperations.prepare_sql_script

Take an SQL script that may contain multiple lines and return a list of statements to feed to successive cursor.execute() calls.

Since few databases are able to process raw SQL scripts in a single cursor.execute() call and PEP 249 doesn't talk about this use case, the default implementation is conservative.

def quote_name(self, name):

overrides django.db.backends.base.operations.BaseDatabaseOperations.quote_name

Return a quoted version of the given table, index, or column name. Do not quote the given name if it's already been quoted.

def return_insert_columns(self, fields):

overrides django.db.backends.base.operations.BaseDatabaseOperations.return_insert_columns

For backends that support returning columns as part of an insert query, return the SQL and params to append to the INSERT query. The returned fragment should contain a format string to hold the appropriate column.

def sequence_reset_by_name_sql(self, style, sequences):

overrides django.db.backends.base.operations.BaseDatabaseOperations.sequence_reset_by_name_sql

Return a list of the SQL statements required to reset sequences passed in sequences.

The style argument is a Style object as returned by either color_style() or no_style() in django.core.management.color.

def sequence_reset_sql(self, style, model_list):

overrides django.db.backends.base.operations.BaseDatabaseOperations.sequence_reset_sql

Return a list of the SQL statements required to reset sequences for the given models.

The style argument is a Style object as returned by either color_style() or no_style() in django.core.management.color.

def set_time_zone_sql(self):

overrides django.db.backends.base.operations.BaseDatabaseOperations.set_time_zone_sql

Return the SQL that will set the connection's time zone.

Return '' if the backend doesn't support time zones.

def sql_flush(self, style, tables, *, reset_sequences=False, allow_cascade=False):

overrides django.db.backends.base.operations.BaseDatabaseOperations.sql_flush

Return a list of SQL statements required to remove all data from the given database tables (without actually removing the tables themselves).

The style argument is a Style object as returned by either color_style() or no_style() in django.core.management.color.

If reset_sequences is True, the list includes SQL statements required to reset the sequences.

The allow_cascade argument determines whether truncation may cascade to tables with foreign keys pointing the tables being truncated. PostgreSQL requires a cascade even if these tables are empty.

def subtract_temporals(self, internal_type, lhs, rhs):

overrides django.db.backends.base.operations.BaseDatabaseOperations.subtract_temporals

Undocumented

def tablespace_sql(self, tablespace, inline=False):

overrides django.db.backends.base.operations.BaseDatabaseOperations.tablespace_sql

Return the SQL that will be used in a query to define the tablespace.

Return '' if the backend doesn't support tablespaces.

If inline is True, append the SQL to a row; otherwise append it to the entire CREATE TABLE or CREATE INDEX statement.

def time_trunc_sql(self, lookup_type, field_name, tzname=None):

overrides django.db.backends.base.operations.BaseDatabaseOperations.time_trunc_sql

Given a lookup_type of 'hour', 'minute' or 'second', return the SQL that truncates the given time or datetime field field_name to a time object with only the given specificity.

If tzname is provided, the given value is truncated in a specific timezone.

def unification_cast_sql(self, output_field):

overrides django.db.backends.base.operations.BaseDatabaseOperations.unification_cast_sql

Given a field instance, return the SQL that casts the result of a union to that type. The resulting string should contain a '%s' placeholder for the expression being cast.

cast_char_field_without_max_length: str =

overrides django.db.backends.base.operations.BaseDatabaseOperations.cast_char_field_without_max_length

Undocumented

cast_data_types: dict[str, str] =

overrides django.db.backends.base.operations.BaseDatabaseOperations.cast_data_types

Undocumented

explain_prefix: str =

overrides django.db.backends.base.operations.BaseDatabaseOperations.explain_prefix

Undocumented