Operations API¶
- class django_spanner.operations.DatabaseOperations(connection)[source]¶
A Spanner-specific version of Django database operations.
- adapt_datefield_value(value)[source]¶
Cast date argument into Spanner DB API DateStr format.
- Parameters
value (object) – A date argument.
- Return type
DateStr- Returns
Formatted Date.
- adapt_datetimefield_value(value)[source]¶
Reformat time argument into Cloud Spanner.
- Parameters
value (object) – A time argument.
- Return type
TimestampStr- Returns
Formatted Time.
- adapt_decimalfield_value(value, max_digits=None, decimal_places=None)[source]¶
Convert value from decimal.Decimal to spanner compatible value. Since spanner supports Numeric storage of decimal and python spanner takes care of the conversion so this is a no-op method call.
- Parameters
value (
decimal.Decimal) – A decimal field value.max_digits (int) – (Optional) A maximum number of digits.
decimal_places (int) – (Optional) The number of decimal places to store with the number.
- Return type
- Returns
decimal value.
- adapt_ipaddressfield_value(value)¶
Transform a string representation of an IP address into the expected type for the backend driver.
- adapt_timefield_value(value)[source]¶
Transform a time value to an object compatible with what is expected by the backend driver for time columns.
- Parameters
value (
datetime.datetime) – A time field value.- Return type
TimestampStr- Returns
Formatted Time.
- adapt_unknown_value(value)¶
Transform a value to something compatible with the backend driver.
This method only depends on the type of the value. It’s designed for cases where the target type isn’t known, such as .raw() SQL queries. As a consequence it may not work perfectly in all circumstances.
- autoinc_sql(table, column)¶
Return any SQL needed to support auto-incrementing primary keys, or None if no SQL is necessary.
This SQL is executed when a table is created.
- binary_placeholder_sql(value)¶
Some backends require special syntax to insert binary content (MySQL for example uses ‘_binary %s’).
- bulk_batch_size(fields, objs)[source]¶
Override the base class method. Returns the maximum number of the query parameters.
- bulk_insert_sql(fields, placeholder_rows)[source]¶
A helper method that stitches multiple values into a single SQL record.
- cache_key_culling_sql()¶
Return an SQL query that retrieves the first cache key greater than the n smallest.
This is used by the ‘db’ cache backend to determine where to start culling.
- check_expression_support(expression)¶
Check that the backend supports the provided expression.
This is used on specific backends to rule out known expressions that have problematic or nonexistent implementations. If the expression has a known problem, the backend should raise NotSupportedError.
- combine_duration_expression(connector, sub_expressions)[source]¶
Combine duration expressions into single one using connector.
- combine_expression(connector, sub_expressions)[source]¶
Recurrently combine expressions into single one using connector.
- compiler(compiler_name)¶
Return the SQLCompiler class corresponding to the given name, in the namespace corresponding to the
compiler_moduleattribute on this backend.
- conditional_expression_supported_in_where_clause(expression)¶
Return True, if the conditional expression is supported in the WHERE clause.
- convert_binaryfield_value(value, expression, connection)[source]¶
Convert Spanner BinaryField value for Django.
- convert_datetimefield_value(value, expression, connection)[source]¶
Convert Spanner DateTimeField value for Django.
- Parameters
value (
DatetimeWithNanoseconds) – A datetime field value.expression (
django.db.models.expressions.BaseExpression) – A query expression.connection (
Connection) – Reference to a Spanner database connection.
- Return type
datetime
- Returns
A TZ-aware datetime.
- convert_timefield_value(value, expression, connection)[source]¶
Convert Spanner TimeField value for Django.
- Parameters
value (
DatetimeWithNanoseconds) – A datetime/time field.expression (
django.db.models.expressions.BaseExpression) – A query expression.connection (
Connection) – Reference to a Spanner database connection.
- Return type
- Returns
A converted datetime.
- convert_uuidfield_value(value, expression, connection)[source]¶
Convert a UUID field to Cloud Spanner.
- date_interval_sql(timedelta)[source]¶
Get a date interval in microseconds.
- Parameters
timedelta (datetime) – A time delta for the interval.
- Return type
- Returns
A SQL statement.
- date_trunc_sql(lookup_type, field_name, tzname=None)[source]¶
Truncate date in the lookup.
- Parameters
Spanner does not support Timezone conversion in DATE_TRUNC function.
- Return type
- Returns
A SQL statement for truncating.
- deferrable_sql()¶
Return the SQL to make a constraint “initially deferred” during a CREATE TABLE statement.
- distinct_sql(fields, params)¶
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.
- end_transaction_sql(success=True)¶
Return the SQL statement required to end a transaction.
- execute_sql_flush(sql_list)¶
Execute a list of SQL statements to flush the database.
- fetch_returned_insert_columns(cursor, returning_params)¶
Given a cursor object that has just performed an INSERT…RETURNING statement into a table, return the newly created data.
- field_cast_sql(db_type, internal_type)¶
Given a column type (e.g. ‘BLOB’, ‘VARCHAR’) and an internal type (e.g. ‘GenericIPAddressField’), return the SQL to cast it before using it in a WHERE statement. The resulting string should contain a ‘%s’ placeholder for the column being searched against.
- for_update_sql(nowait=False, skip_locked=False, of=(), no_key=False)¶
Return the FOR UPDATE SQL clause to lock rows for an update operation.
- 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.
- format_for_duration_arithmetic(sql)[source]¶
Do nothing since formatting is handled in the custom function.
- get_db_converters(expression)[source]¶
Get a list of functions needed to convert field data.
- Parameters
expression (
django.db.models.expressions.BaseExpression) – A query expression to convert.- Return type
- Returns
Converter functions to apply to Spanner field values.
- integer_field_range(internal_type)¶
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.
- last_executed_query(cursor, sql, params)¶
Return a string of the query last executed by the given cursor, with placeholders replaced with actual values.
sqlis the raw query containing placeholders andparamsis 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.
- last_insert_id(cursor, table_name, pk_name)¶
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.
pk_nameis the name of the primary-key column.
- limit_offset_sql(low_mark, high_mark)¶
Return LIMIT/OFFSET SQL clause.
- lookup_cast(lookup_type, internal_type=None)[source]¶
Cast text lookups to string to allow things like filter(x__contains=4).
- 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.
- max_name_length()[source]¶
Get the maximum length of Spanner table and column names.
See also: https://cloud.google.com/spanner/quotas#tables
- Return type
- Returns
Maximum length of the name of the table.
- modify_insert_params(placeholder, params)¶
Allow modification of insert parameters. Needed for Oracle Spatial backend due to #10888.
- pk_default_value()¶
Return the value to use during an INSERT statement to specify that the field should use its default value.
- prep_for_iexact_query(x)¶
Lookups that use this method use REGEXP_CONTAINS instead of LIKE.
- prepare_sql_script(sql)¶
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.
- process_clob(value)¶
Return the value of a CLOB column, for backends that return a locator object that requires additional processing.
- quote_name(name)[source]¶
Return a quoted version of the given table or column name. Also, applies backticks to the name that either contain ‘-’ or ‘ ‘, or is a Cloud Spanner’s reserved keyword.
Spanner says “column name not valid” if spaces or hyphens are present (although according to the documantation, any character should be allowed in quoted identifiers). Replace problematic characters when running the Django tests to prevent crashes. (Don’t modify names in normal operation to prevent the possibility of colliding with another column.)
See: https://github.com/googleapis/python-spanner-django/issues/204
- regex_lookup(lookup_type)¶
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.
If the feature is not supported (or part of it is not supported), raise NotImplementedError.
- return_insert_columns(fields)¶
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.
- savepoint_commit_sql(sid)¶
Return the SQL for committing the given savepoint.
- savepoint_create_sql(sid)¶
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.
- savepoint_rollback_sql(sid)¶
Return the SQL for rolling back the given savepoint.
- sequence_reset_by_name_sql(style, sequences)¶
Return a list of the SQL statements required to reset sequences passed in
sequences.The
styleargument is a Style object as returned by either color_style() or no_style() in django.core.management.color.
- sequence_reset_sql(style, model_list)¶
Return a list of the SQL statements required to reset sequences for the given models.
The
styleargument is a Style object as returned by either color_style() or no_style() in django.core.management.color.
- set_time_zone_sql()¶
Return the SQL that will set the connection’s time zone.
Return ‘’ if the backend doesn’t support time zones.
- sql_flush(style, tables, reset_sequences=False, allow_cascade=False)[source]¶
Override the base class method. Returns a list of SQL statements required to remove all data from the given database tables (without actually removing the tables themselves).
- Parameters
- Return type
- Returns
A list of SQL statements required to remove all data from
the given database tables.
- start_transaction_sql()¶
Return the SQL statement required to start a transaction.
- tablespace_sql(tablespace, inline=False)¶
Return the SQL that will be used in a query to define the tablespace.
Return ‘’ if the backend doesn’t support tablespaces.
If
inlineis True, append the SQL to a row; otherwise append it to the entire CREATE TABLE or CREATE INDEX statement.
- unification_cast_sql(output_field)¶
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.
- validate_autopk_value(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.
- window_frame_rows_start_end(start=None, end=None)¶
Return SQL for start and end points in an OVER clause window frame.
- year_lookup_bounds_for_date_field(value)¶
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.
valueis an int, containing the looked-up year.
- year_lookup_bounds_for_datetime_field(value)¶
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.
valueis an int, containing the looked-up year.
