blinkster: comparison web/lib/django/db/backends/__init_

equal deleted inserted replaced

-:8d941af65caf
+:77b6da96e6f1
+import decimal
+from threading import local
+from django.db import DEFAULT_DB_ALIAS
+from django.db.backends import util
+from django.utils import datetime_safe
+from django.utils.importlib import import_module
+class BaseDatabaseWrapper(local):
+"""
+Represents a database connection.
+"""
+ops = None
+def __init__(self, settings_dict, alias=DEFAULT_DB_ALIAS):
+# `settings_dict` should be a dictionary containing keys such as
+# NAME, USER, etc. It's called `settings_dict` instead of `settings`
+# to disambiguate it from Django settings modules.
+self.connection = None
+self.queries = []
+self.settings_dict = settings_dict
+self.alias = alias
+def __eq__(self, other):
+return self.settings_dict == other.settings_dict
+def __ne__(self, other):
+return not self == other
+def _commit(self):
+if self.connection is not None:
+return self.connection.commit()
+def _rollback(self):
+if self.connection is not None:
+return self.connection.rollback()
+def _enter_transaction_management(self, managed):
+"""
+A hook for backend-specific changes required when entering manual
+transaction handling.
+"""
+pass
+def _leave_transaction_management(self, managed):
+"""
+A hook for backend-specific changes required when leaving manual
+transaction handling. Will usually be implemented only when
+_enter_transaction_management() is also required.
+"""
+pass
+def _savepoint(self, sid):
+if not self.features.uses_savepoints:
+return
+self.cursor().execute(self.ops.savepoint_create_sql(sid))
+def _savepoint_rollback(self, sid):
+if not self.features.uses_savepoints:
+return
+self.cursor().execute(self.ops.savepoint_rollback_sql(sid))
+def _savepoint_commit(self, sid):
+if not self.features.uses_savepoints:
+return
+self.cursor().execute(self.ops.savepoint_commit_sql(sid))
+def close(self):
+if self.connection is not None:
+self.connection.close()
+self.connection = None
+def cursor(self):
+from django.conf import settings
+cursor = self._cursor()
+if settings.DEBUG:
+return self.make_debug_cursor(cursor)
+return cursor
+def make_debug_cursor(self, cursor):
+return util.CursorDebugWrapper(cursor, self)
+class BaseDatabaseFeatures(object):
+allows_group_by_pk = False
+# True if django.db.backend.utils.typecast_timestamp is used on values
+# returned from dates() calls.
+needs_datetime_string_cast = True
+empty_fetchmany_value = []
+update_can_self_select = True
+interprets_empty_strings_as_nulls = False
+can_use_chunked_reads = True
+can_return_id_from_insert = False
+uses_autocommit = False
+uses_savepoints = False
+# If True, don't use integer foreign keys referring to, e.g., positive
+# integer primary keys.
+related_fields_match_type = False
+allow_sliced_subqueries = True
+class BaseDatabaseOperations(object):
+"""
+This class encapsulates all backend-specific differences, such as the way
+a backend performs ordering or calculates the ID of a recently-inserted
+row.
+"""
+compiler_module = "django.db.models.sql.compiler"
+def __init__(self):
+self._cache = {}
+def autoinc_sql(self, table, column):
+"""
+Returns 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.
+"""
+return None
+def date_extract_sql(self, lookup_type, field_name):
+"""
+Given a lookup_type of 'year', 'month' or 'day', returns the SQL that
+extracts a value from the given date field field_name.
+"""
+raise NotImplementedError()
+def date_trunc_sql(self, lookup_type, field_name):
+"""
+Given a lookup_type of 'year', 'month' or 'day', returns the SQL that
+truncates the given date field field_name to a DATE object with only
+the given specificity.
+"""
+raise NotImplementedError()
+def datetime_cast_sql(self):
+"""
+Returns the SQL necessary to cast a datetime value so that it will be
+retrieved as a Python datetime object instead of a string.
+This SQL should include a '%s' in place of the field's name.
+"""
+return "%s"
+def deferrable_sql(self):
+"""
+Returns the SQL necessary to make a constraint "initially deferred"
+during a CREATE TABLE statement.
+"""
+return ''
+def drop_foreignkey_sql(self):
+"""
+Returns the SQL command that drops a foreign key.
+"""
+return "DROP CONSTRAINT"
+def drop_sequence_sql(self, table):
+"""
+Returns any SQL necessary to drop the sequence for the given table.
+Returns None if no SQL is necessary.
+"""
+return None
+def fetch_returned_insert_id(self, cursor):
+"""
+Given a cursor object that has just performed an INSERT...RETURNING
+statement into a table that has an auto-incrementing ID, returns the
+newly created ID.
+"""
+return cursor.fetchone()[0]
+def field_cast_sql(self, db_type):
+"""
+Given a column type (e.g. 'BLOB', 'VARCHAR'), returns the SQL necessary
+to cast it before using it in a WHERE statement. Note that the
+resulting string should contain a '%s' placeholder for the column being
+searched against.
+"""
+return '%s'
+def force_no_ordering(self):
+"""
+Returns a list used in the "ORDER BY" clause to force no ordering at
+all. Returning an empty list means that nothing will be included in the
+ordering.
+"""
+return []
+def fulltext_search_sql(self, field_name):
+"""
+Returns the SQL WHERE clause to use in order to perform a full-text
+search of the given field_name. Note that the resulting string should
+contain a '%s' placeholder for the value being searched against.
+"""
+raise NotImplementedError('Full-text search is not implemented for this database backend')
+def last_executed_query(self, cursor, sql, params):
+"""
+Returns 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.
+"""
+from django.utils.encoding import smart_unicode, force_unicode
+# Convert params to contain Unicode values.
+to_unicode = lambda s: force_unicode(s, strings_only=True, errors='replace')
+if isinstance(params, (list, tuple)):
+u_params = tuple([to_unicode(val) for val in params])
+else:
+u_params = dict([(to_unicode(k), to_unicode(v)) for k, v in params.items()])
+return smart_unicode(sql) % u_params
+def last_insert_id(self, 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, returns the newly created ID.
+This method also receives the table name and the name of the primary-key
+column.
+"""
+return cursor.lastrowid
+def lookup_cast(self, lookup_type):
+"""
+Returns the string to use in a query when performing lookups
+("contains", "like", etc). The resulting string should contain a '%s'
+placeholder for the column being searched against.
+"""
+return "%s"
+def max_name_length(self):
+"""
+Returns the maximum length of table and column names, or None if there
+is no limit.
+"""
+return None
+def no_limit_value(self):
+"""
+Returns the value to use for the LIMIT when we are wanting "LIMIT
+infinity". Returns None if the limit clause can be omitted in this case.
+"""
+raise NotImplementedError
+def pk_default_value(self):
+"""
+Returns the value to use during an INSERT statement to specify that
+the field should use its default value.
+"""
+return 'DEFAULT'
+def process_clob(self, value):
+"""
+Returns the value of a CLOB column, for backends that return a locator
+object that requires additional processing.
+"""
+return value
+def return_insert_id(self):
+"""
+For backends that support returning the last insert ID as part
+of an insert query, this method returns the SQL and params to
+append to the INSERT query. The returned fragment should
+contain a format string to hold the appropriate column.
+"""
+pass
+def compiler(self, compiler_name):
+"""
+Returns the SQLCompiler class corresponding to the given name,
+in the namespace corresponding to the `compiler_module` attribute
+on this backend.
+"""
+if compiler_name not in self._cache:
+self._cache[compiler_name] = getattr(
+import_module(self.compiler_module), compiler_name
+)
+return self._cache[compiler_name]
+def quote_name(self, name):
+"""
+Returns a quoted version of the given table, index or column name. Does
+not quote the given name if it's already been quoted.
+"""
+raise NotImplementedError()
+def random_function_sql(self):
+"""
+Returns a SQL expression that returns a random value.
+"""
+return 'RANDOM()'
+def regex_lookup(self, lookup_type):
+"""
+Returns the string to use in a query when performing regular expression
+lookups (using "regex" or "iregex"). The resulting string should
+contain a '%s' placeholder for the column being searched against.
+If the feature is not supported (or part of it is not supported), a
+NotImplementedError exception can be raised.
+"""
+raise NotImplementedError
+def savepoint_create_sql(self, sid):
+"""
+Returns 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.
+"""
+raise NotImplementedError
+def savepoint_commit_sql(self, sid):
+"""
+Returns the SQL for committing the given savepoint.
+"""
+raise NotImplementedError
+def savepoint_rollback_sql(self, sid):
+"""
+Returns the SQL for rolling back the given savepoint.
+"""
+raise NotImplementedError
+def sql_flush(self, style, tables, sequences):
+"""
+Returns 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.
+"""
+raise NotImplementedError()
+def sequence_reset_sql(self, style, model_list):
+"""
+Returns 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.
+"""
+return [] # No sequence reset required by default.
+def start_transaction_sql(self):
+"""
+Returns the SQL statement required to start a transaction.
+"""
+return "BEGIN;"
+def tablespace_sql(self, tablespace, inline=False):
+"""
+Returns the SQL that will be appended to tables or rows to define
+a tablespace. Returns '' if the backend doesn't use tablespaces.
+"""
+return ''
+def prep_for_like_query(self, x):
+"""Prepares a value for use in a LIKE query."""
+from django.utils.encoding import smart_unicode
+return smart_unicode(x).replace("\\", "\\\\").replace("%", "\%").replace("_", "\_")
+# Same as prep_for_like_query(), but called for "iexact" matches, which
+# need not necessarily be implemented using "LIKE" in the backend.
+prep_for_iexact_query = prep_for_like_query
+def value_to_db_date(self, value):
+"""
+Transform a date value to an object compatible with what is expected
+by the backend driver for date columns.
+"""
+if value is None:
+return None
+return datetime_safe.new_date(value).strftime('%Y-%m-%d')
+def value_to_db_datetime(self, value):
+"""
+Transform a datetime value to an object compatible with what is expected
+by the backend driver for datetime columns.
+"""
+if value is None:
+return None
+return unicode(value)
+def value_to_db_time(self, value):
+"""
+Transform a datetime value to an object compatible with what is expected
+by the backend driver for time columns.
+"""
+if value is None:
+return None
+return unicode(value)
+def value_to_db_decimal(self, value, max_digits, decimal_places):
+"""
+Transform a decimal.Decimal value to an object compatible with what is
+expected by the backend driver for decimal (numeric) columns.
+"""
+if value is None:
+return None
+return util.format_number(value, max_digits, decimal_places)
+def year_lookup_bounds(self, value):
+"""
+Returns a two-elements list with the lower and upper bound to be used
+with a BETWEEN operator to query a field value using a year lookup
+`value` is an int, containing the looked-up year.
+"""
+first = '%s-01-01 00:00:00'
+second = '%s-12-31 23:59:59.999999'
+return [first % value, second % value]
+def year_lookup_bounds_for_date_field(self, value):
+"""
+Returns 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
+`value` is an int, containing the looked-up year.
+By default, it just calls `self.year_lookup_bounds`. Some backends need
+this hook because on their DB date fields can't be compared to values
+which include a time part.
+"""
+return self.year_lookup_bounds(value)
+def convert_values(self, value, field):
+"""Coerce the value returned by the database backend into a consistent type that
+is compatible with the field type.
+"""
+internal_type = field.get_internal_type()
+if internal_type == 'DecimalField':
+return value
+elif internal_type and internal_type.endswith('IntegerField') or internal_type == 'AutoField':
+return int(value)
+elif internal_type in ('DateField', 'DateTimeField', 'TimeField'):
+return value
+# No field, or the field isn't known to be a decimal or integer
+# Default to a float
+return float(value)
+def check_aggregate_support(self, aggregate_func):
+"""Check that the backend supports the provided aggregate
+This is used on specific backends to rule out known aggregates
+that are known to have faulty implementations. If the named
+aggregate function has a known problem, the backend should
+raise NotImplemented.
+"""
+pass
+def combine_expression(self, connector, sub_expressions):
+"""Combine a list of subexpressions into a single expression, using
+the provided connecting operator. This is required because operators
+can vary between backends (e.g., Oracle with %% and &) and between
+subexpression types (e.g., date expressions)
+"""
+conn = ' %s ' % connector
+return conn.join(sub_expressions)
+class BaseDatabaseIntrospection(object):
+"""
+This class encapsulates all backend-specific introspection utilities
+"""
+data_types_reverse = {}
+def __init__(self, connection):
+self.connection = connection
+def get_field_type(self, data_type, description):
+"""Hook for a database backend to use the cursor description to
+match a Django field type to a database column.
+For Oracle, the column data_type on its own is insufficient to
+distinguish between a FloatField and IntegerField, for example."""
+return self.data_types_reverse[data_type]
+def table_name_converter(self, name):
+"""Apply a conversion to the name for the purposes of comparison.
+The default table name converter is for case sensitive comparison.
+"""
+return name
+def table_names(self):
+"Returns a list of names of all tables that exist in the database."
+cursor = self.connection.cursor()
+return self.get_table_list(cursor)
+def django_table_names(self, only_existing=False):
+"""
+Returns a list of all table names that have associated Django models and
+are in INSTALLED_APPS.
+If only_existing is True, the resulting list will only include the tables
+that actually exist in the database.
+"""
+from django.db import models, router
+tables = set()
+for app in models.get_apps():
+for model in models.get_models(app):
+if not model._meta.managed:
+continue
+if not router.allow_syncdb(self.connection.alias, model):
+continue
+tables.add(model._meta.db_table)
+tables.update([f.m2m_db_table() for f in model._meta.local_many_to_many])
+if only_existing:
+tables = [t for t in tables if self.table_name_converter(t) in self.table_names()]
+return tables
+def installed_models(self, tables):
+"Returns a set of all models represented by the provided list of table names."
+from django.db import models, router
+all_models = []
+for app in models.get_apps():
+for model in models.get_models(app):
+if router.allow_syncdb(self.connection.alias, model):
+all_models.append(model)
+return set([m for m in all_models
+if self.table_name_converter(m._meta.db_table) in map(self.table_name_converter, tables)
+])
+def sequence_list(self):
+"Returns a list of information about all DB sequences for all models in all apps."
+from django.db import models, router
+apps = models.get_apps()
+sequence_list = []
+for app in apps:
+for model in models.get_models(app):
+if not model._meta.managed:
+continue
+if not router.allow_syncdb(self.connection.alias, model):
+continue
+for f in model._meta.local_fields:
+if isinstance(f, models.AutoField):
+sequence_list.append({'table': model._meta.db_table, 'column': f.column})
+break # Only one AutoField is allowed per model, so don't bother continuing.
+for f in model._meta.local_many_to_many:
+# If this is an m2m using an intermediate table,
+# we don't need to reset the sequence.
+if f.rel.through is None:
+sequence_list.append({'table': f.m2m_db_table(), 'column': None})
+return sequence_list
+class BaseDatabaseClient(object):
+"""
+This class encapsulates all backend-specific methods for opening a
+client shell.
+"""
+# This should be a string representing the name of the executable
+# (e.g., "psql"). Subclasses must override this.
+executable_name = None
+def __init__(self, connection):
+# connection is an instance of BaseDatabaseWrapper.
+self.connection = connection
+def runshell(self):
+raise NotImplementedError()
+class BaseDatabaseValidation(object):
+"""
+This class encapsualtes all backend-specific model validation.
+"""
+def __init__(self, connection):
+self.connection = connection
+def validate_field(self, errors, opts, f):
+"By default, there is no backend-specific validation"
+pass