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       import re
       import sys
       from django.core.management.color import no_style
       from django.db import transaction, models
       from django.db.utils import DatabaseError
       from django.db.backends.util import truncate_name
       from django.db.backends.creation import BaseDatabaseCreation
       from django.db.models.fields import NOT_PROVIDED
       from django.dispatch import dispatcher
       from django.conf import settings
       from django.utils.datastructures import SortedDict
       try:
           from django.utils.functional import cached_property
       except ImportError:
           class cached_property(object):
               """
               Decorator that creates converts a method with a single
               self argument into a property cached on the instance.
               """
               def __init__(self, func):
                   self.func = func
               def __get__(self, instance, type):
                   res = instance.__dict__[self.func.__name__] = self.func(instance)
                   return res
       from south.logger import get_logger
       def alias(attrname):
           """
           Returns a function which calls 'attrname' - for function aliasing.
           We can't just use foo = bar, as this breaks subclassing.
           """
           def func(self, *args, **kwds):
               return getattr(self, attrname)(*args, **kwds)
           return func
       def invalidate_table_constraints(func):
           def _cache_clear(self, table, *args, **opts):
               self._set_cache(table, value=INVALID)
               return func(self, table, *args, **opts)
           return _cache_clear
       def delete_column_constraints(func):
           def _column_rm(self, table, column, *args, **opts):
               self._set_cache(table, column, value=[])
               return func(self, table, column, *args, **opts)
           return _column_rm
       def copy_column_constraints(func):
           def _column_cp(self, table, column_old, column_new, *args, **opts):
               db_name = self._get_setting('NAME')
               self._set_cache(table, column_new, value=self.lookup_constraint(db_name, table, column_old))
               return func(self, table, column_old, column_new, *args, **opts)
           return _column_cp
       class INVALID(Exception):
           def __repr__(self):
               return 'INVALID'
       class DryRunError(ValueError):
           pass
       class DatabaseOperations(object):
           """
           Generic SQL implementation of the DatabaseOperations.
           Some of this code comes from Django Evolution.
           """
           alter_string_set_type = 'ALTER COLUMN %(column)s TYPE %(type)s'
           alter_string_set_null = 'ALTER COLUMN %(column)s DROP NOT NULL'
           alter_string_drop_null = 'ALTER COLUMN %(column)s SET NOT NULL'
           delete_check_sql = 'ALTER TABLE %(table)s DROP CONSTRAINT %(constraint)s'
           add_column_string = 'ALTER TABLE %s ADD COLUMN %s;'
           delete_unique_sql = "ALTER TABLE %s DROP CONSTRAINT %s"
           delete_foreign_key_sql = 'ALTER TABLE %(table)s DROP CONSTRAINT %(constraint)s'
           max_index_name_length = 63
           drop_index_string = 'DROP INDEX %(index_name)s'
           delete_column_string = 'ALTER TABLE %s DROP COLUMN %s CASCADE;'
           create_primary_key_string = "ALTER TABLE %(table)s ADD CONSTRAINT %(constraint)s PRIMARY KEY (%(columns)s)"
           delete_primary_key_sql = "ALTER TABLE %(table)s DROP CONSTRAINT %(constraint)s"
           add_check_constraint_fragment = "ADD CONSTRAINT %(constraint)s CHECK (%(check)s)"
           rename_table_sql = "ALTER TABLE %s RENAME TO %s;"
           backend_name = None
           default_schema_name = "public"
           # Features
           allows_combined_alters = True
           supports_foreign_keys = True
           has_check_constraints = True
           has_booleans = True
           @cached_property
           def has_ddl_transactions(self):
               """
               Tests the database using feature detection to see if it has
               transactional DDL support.
               """
               self._possibly_initialise()
               connection = self._get_connection()
               if hasattr(connection.features, "confirm") and not connection.features._confirmed:
                   connection.features.confirm()
               # Django 1.3's MySQLdb backend doesn't raise DatabaseError
               exceptions = (DatabaseError, )
               try:
                   from MySQLdb import OperationalError
                   exceptions += (OperationalError, )
               except ImportError:
                   pass
               # Now do the test
               if getattr(connection.features, 'supports_transactions', True):
                   cursor = connection.cursor()
                   self.start_transaction()
                   cursor.execute('CREATE TABLE DDL_TRANSACTION_TEST (X INT)')
                   self.rollback_transaction()
                   try:
                       try:
                           cursor.execute('CREATE TABLE DDL_TRANSACTION_TEST (X INT)')
                       except exceptions:
                           return False
                       else:
                           return True
                   finally:
                       cursor.execute('DROP TABLE DDL_TRANSACTION_TEST')
               else:
                   return False
           def __init__(self, db_alias):
               self.debug = False
               self.deferred_sql = []
               self.dry_run = False
               self.pending_transactions = 0
               self.pending_create_signals = []
               self.db_alias = db_alias
               self._constraint_cache = {}
               self._initialised = False
           def lookup_constraint(self, db_name, table_name, column_name=None):
               """ return a set() of constraints for db_name.table_name.column_name """
               def _lookup():
                   table = self._constraint_cache[db_name][table_name]
                   if table is INVALID:
                       raise INVALID
                   elif column_name is None:
                       return table.items()
                   else:
                       return table[column_name]
               try:
                   ret = _lookup()
                   return ret
               except INVALID:
                   del self._constraint_cache[db_name][table_name]
                   self._fill_constraint_cache(db_name, table_name)
               except KeyError:
                   if self._is_valid_cache(db_name, table_name):
                       return []
                   self._fill_constraint_cache(db_name, table_name)
               return self.lookup_constraint(db_name, table_name, column_name)
           def _set_cache(self, table_name, column_name=None, value=INVALID):
               db_name = self._get_setting('NAME')
               try:
                   if column_name is not None:
                       self._constraint_cache[db_name][table_name][column_name] = value
                   else:
                       self._constraint_cache[db_name][table_name] = value
               except (LookupError, TypeError):
                   pass
           def _is_valid_cache(self, db_name, table_name):
               # we cache per-table so if the table is there it is valid
               try:
                   return self._constraint_cache[db_name][table_name] is not INVALID
               except KeyError:
                   return False
           def _is_multidb(self):
               try:
                   from django.db import connections
                   connections  # Prevents "unused import" warning
               except ImportError:
                   return False
               else:
                   return True
           def _get_connection(self):
               """
               Returns a django connection for a given DB Alias
               """
               if self._is_multidb():
                   from django.db import connections
                   return connections[self.db_alias]
               else:
                   from django.db import connection
                   return connection
           def _get_setting(self, setting_name):
               """
               Allows code to get a setting (like, for example, STORAGE_ENGINE)
               """
               setting_name = setting_name.upper()
               connection = self._get_connection()
               if self._is_multidb():
                   # Django 1.2 and above
                   return connection.settings_dict[setting_name]
               else:
                   # Django 1.1 and below
                   return getattr(settings, "DATABASE_%s" % setting_name)
           def _has_setting(self, setting_name):
               """
               Existence-checking version of _get_setting.
               """
               try:
                   self._get_setting(setting_name)
               except (KeyError, AttributeError):
                   return False
               else:
                   return True
           def _get_schema_name(self):
               try:
                   return self._get_setting('schema')
               except (KeyError, AttributeError):
                   return self.default_schema_name
           def _possibly_initialise(self):
               if not self._initialised:
                   self.connection_init()
                   self._initialised = True
           def connection_init(self):
               """
               Run before any SQL to let database-specific config be sent as a command,
               e.g. which storage engine (MySQL) or transaction serialisability level.
               """
               pass
           def quote_name(self, name):
               """
               Uses the database backend to quote the given table/column name.
               """
               return self._get_connection().ops.quote_name(name)
           def execute(self, sql, params=[]):
               """
               Executes the given SQL statement, with optional parameters.
               If the instance's debug attribute is True, prints out what it executes.
               """
               self._possibly_initialise()
               cursor = self._get_connection().cursor()
               if self.debug:
                   print "   = %s" % sql, params
               if self.dry_run:
                   return []
               get_logger().debug('execute "%s" with params "%s"' % (sql, params))
               try:
                   cursor.execute(sql, params)
               except DatabaseError, e:
                   print >> sys.stderr, 'FATAL ERROR - The following SQL query failed: %s' % sql
                   print >> sys.stderr, 'The error was: %s' % e
                   raise
               try:
                   return cursor.fetchall()
               except:
                   return []
           def execute_many(self, sql, regex=r"(?mx) ([^';]* (?:'[^']*'[^';]*)*)", comment_regex=r"(?mx) (?:^\s*$)|(?:--.*$)"):
               """
               Takes a SQL file and executes it as many separate statements.
               (Some backends, such as Postgres, don't work otherwise.)
               """
               # Be warned: This function is full of dark magic. Make sure you really
               # know regexes before trying to edit it.
               # First, strip comments
               sql = "\n".join([x.strip().replace("%", "%%") for x in re.split(comment_regex, sql) if x.strip()])
               # Now execute each statement
               for st in re.split(regex, sql)[1:][::2]:
                   self.execute(st)
           def add_deferred_sql(self, sql):
               """
               Add a SQL statement to the deferred list, that won't be executed until
               this instance's execute_deferred_sql method is run.
               """
               self.deferred_sql.append(sql)
           def execute_deferred_sql(self):
               """
               Executes all deferred SQL, resetting the deferred_sql list
               """
               for sql in self.deferred_sql:
                   self.execute(sql)
               self.deferred_sql = []
           def clear_deferred_sql(self):
               """
               Resets the deferred_sql list to empty.
               """
               self.deferred_sql = []
           def clear_run_data(self, pending_creates = None):
               """
               Resets variables to how they should be before a run. Used for dry runs.
               If you want, pass in an old panding_creates to reset to.
               """
               self.clear_deferred_sql()
               self.pending_create_signals = pending_creates or []
           def get_pending_creates(self):
               return self.pending_create_signals
           @invalidate_table_constraints
           def create_table(self, table_name, fields):
               """
               Creates the table 'table_name'. 'fields' is a tuple of fields,
               each repsented by a 2-part tuple of field name and a
               django.db.models.fields.Field object
               """
               if len(table_name) > 63:
                   print "   ! WARNING: You have a table name longer than 63 characters; this will not fully work on PostgreSQL or MySQL."
               # avoid default values in CREATE TABLE statements (#925)
               for field_name, field in fields:
                   field._suppress_default = True
               columns = [
                   self.column_sql(table_name, field_name, field)
                   for field_name, field in fields
+              ]
               self.execute('CREATE TABLE %s (%s);' % (
                   self.quote_name(table_name),
                   ', '.join([col for col in columns if col]),
               ))
           add_table = alias('create_table')  # Alias for consistency's sake
           @invalidate_table_constraints
           def rename_table(self, old_table_name, table_name):
               """
               Renames the table 'old_table_name' to 'table_name'.
               """
               if old_table_name == table_name:
                   # Short-circuit out.
                   return
               params = (self.quote_name(old_table_name), self.quote_name(table_name))
               self.execute(self.rename_table_sql % params)
               # Invalidate the not-yet-indexed table
               self._set_cache(table_name, value=INVALID)
           @invalidate_table_constraints
           def delete_table(self, table_name, cascade=True):
               """
               Deletes the table 'table_name'.
               """
               params = (self.quote_name(table_name), )
               if cascade:
                   self.execute('DROP TABLE %s CASCADE;' % params)
               else:
                   self.execute('DROP TABLE %s;' % params)
           drop_table = alias('delete_table')
           @invalidate_table_constraints
           def clear_table(self, table_name):
               """
               Deletes all rows from 'table_name'.
               """
               params = (self.quote_name(table_name), )
               self.execute('DELETE FROM %s;' % params)
           @invalidate_table_constraints
           def add_column(self, table_name, name, field, keep_default=True):
               """
               Adds the column 'name' to the table 'table_name'.
               Uses the 'field' paramater, a django.db.models.fields.Field instance,
               to generate the necessary sql
               @param table_name: The name of the table to add the column to
               @param name: The name of the column to add
               @param field: The field to use
               """
               sql = self.column_sql(table_name, name, field)
               if sql:
                   params = (
                       self.quote_name(table_name),
                       sql,
+                  )
                   sql = self.add_column_string % params
                   self.execute(sql)
                   # Now, drop the default if we need to
                   if not keep_default and field.default is not None:
                       field.default = NOT_PROVIDED
                       self.alter_column(table_name, name, field, explicit_name=False, ignore_constraints=True)
           def _db_type_for_alter_column(self, field):
               """
               Returns a field's type suitable for ALTER COLUMN.
               By default it just returns field.db_type().
               To be overriden by backend specific subclasses
               @param field: The field to generate type for
               """
               try:
                   return field.db_type(connection=self._get_connection())
               except TypeError:
                   return field.db_type()
           def _alter_add_column_mods(self, field, name, params, sqls):
               """
               Subcommand of alter_column that modifies column definitions beyond
               the type string -- e.g. adding constraints where they cannot be specified
               as part of the type (overrideable)
               """
               pass
           def _alter_set_defaults(self, field, name, params, sqls):
               "Subcommand of alter_column that sets default values (overrideable)"
               # Next, set any default
               if not field.null and field.has_default():
                   default = field.get_default()
                   sqls.append(('ALTER COLUMN %s SET DEFAULT %%s ' % (self.quote_name(name),), [default]))
               else:
                   sqls.append(('ALTER COLUMN %s DROP DEFAULT' % (self.quote_name(name),), []))
           @invalidate_table_constraints
           def alter_column(self, table_name, name, field, explicit_name=True, ignore_constraints=False):
               """
               Alters the given column name so it will match the given field.
               Note that conversion between the two by the database must be possible.
               Will not automatically add _id by default; to have this behavour, pass
               explicit_name=False.
               @param table_name: The name of the table to add the column to
               @param name: The name of the column to alter
               @param field: The new field definition to use
               """
               if self.dry_run:
                   if self.debug:
                       print '   - no dry run output for alter_column() due to dynamic DDL, sorry'
                   return
               # hook for the field to do any resolution prior to it's attributes being queried
               if hasattr(field, 'south_init'):
                   field.south_init()
               # Add _id or whatever if we need to
               field.set_attributes_from_name(name)
               if not explicit_name:
                   name = field.column
               else:
                   field.column = name
               if not ignore_constraints:
                   # Drop all check constraints. Note that constraints will be added back
                   # with self.alter_string_set_type and self.alter_string_drop_null.
                   if self.has_check_constraints:
                       check_constraints = self._constraints_affecting_columns(table_name, [name], "CHECK")
                       for constraint in check_constraints:
                           self.execute(self.delete_check_sql % {
                               'table': self.quote_name(table_name),
                               'constraint': self.quote_name(constraint),
                           })
                   # Drop all foreign key constraints
                   try:
                       self.delete_foreign_key(table_name, name)
                   except ValueError:
                       # There weren't any
                       pass
               # First, change the type
               params = {
                   "column": self.quote_name(name),
                   "type": self._db_type_for_alter_column(field),
                   "table_name": table_name
+              }
               # SQLs is a list of (SQL, values) pairs.
               sqls = []
               # Only alter the column if it has a type (Geometry ones sometimes don't)
               if params["type"] is not None:
                   sqls.append((self.alter_string_set_type % params, []))
               # Add any field- and backend- specific modifications
               self._alter_add_column_mods(field, name, params, sqls)
               # Next, nullity
               if field.null:
                   sqls.append((self.alter_string_set_null % params, []))
               else:
                   sqls.append((self.alter_string_drop_null % params, []))
               # Next, set any default
               self._alter_set_defaults(field, name, params, sqls)
               # Finally, actually change the column
               if self.allows_combined_alters:
                   sqls, values = zip(*sqls)
                   self.execute(
                       "ALTER TABLE %s %s;" % (self.quote_name(table_name), ", ".join(sqls)),
                       flatten(values),
+                  )
               else:
                   # Databases like e.g. MySQL don't like more than one alter at once.
                   for sql, values in sqls:
                       self.execute("ALTER TABLE %s %s;" % (self.quote_name(table_name), sql), values)
               if not ignore_constraints:
                   # Add back FK constraints if needed
                   if field.rel and self.supports_foreign_keys:
                       self.execute(
                           self.foreign_key_sql(
                               table_name,
                               field.column,
                               field.rel.to._meta.db_table,
                               field.rel.to._meta.get_field(field.rel.field_name).column
+                          )
+                      )
           def _fill_constraint_cache(self, db_name, table_name):
               schema = self._get_schema_name()
               ifsc_tables = ["constraint_column_usage", "key_column_usage"]
               self._constraint_cache.setdefault(db_name, {})
               self._constraint_cache[db_name][table_name] = {}
               for ifsc_table in ifsc_tables:
                   rows = self.execute("""
                       SELECT kc.constraint_name, kc.column_name, c.constraint_type
                       FROM information_schema.%s AS kc
                       JOIN information_schema.table_constraints AS c ON
                           kc.table_schema = c.table_schema AND
                           kc.table_name = c.table_name AND
                           kc.constraint_name = c.constraint_name
                       WHERE
                           kc.table_schema = %%s AND
                           kc.table_name = %%s
                   """ % ifsc_table, [schema, table_name])
                   for constraint, column, kind in rows:
                       self._constraint_cache[db_name][table_name].setdefault(column, set())
                       self._constraint_cache[db_name][table_name][column].add((kind, constraint))
               return
           def _constraints_affecting_columns(self, table_name, columns, type="UNIQUE"):
               """
               Gets the names of the constraints affecting the given columns.
               If columns is None, returns all constraints of the type on the table.
               """
               if self.dry_run:
                   raise DryRunError("Cannot get constraints for columns.")
               if columns is not None:
                   columns = set(map(lambda s: s.lower(), columns))
               db_name = self._get_setting('NAME')
               cnames = {}
               for col, constraints in self.lookup_constraint(db_name, table_name):
                   for kind, cname in constraints:
                       if kind == type:
                           cnames.setdefault(cname, set())
                           cnames[cname].add(col.lower())
               for cname, cols in cnames.items():
                   if cols == columns or columns is None:
                       yield cname
           @invalidate_table_constraints
           def create_unique(self, table_name, columns):
               """
               Creates a UNIQUE constraint on the columns on the given table.
               """
               if not isinstance(columns, (list, tuple)):
                   columns = [columns]
               name = self.create_index_name(table_name, columns, suffix="_uniq")
               cols = ", ".join(map(self.quote_name, columns))
               self.execute("ALTER TABLE %s ADD CONSTRAINT %s UNIQUE (%s)" % (
                   self.quote_name(table_name),
                   self.quote_name(name),
                   cols,
               ))
               return name
           @invalidate_table_constraints
           def delete_unique(self, table_name, columns):
               """
               Deletes a UNIQUE constraint on precisely the columns on the given table.
               """
               if not isinstance(columns, (list, tuple)):
                   columns = [columns]
               # Dry runs mean we can't do anything.
               if self.dry_run:
                   if self.debug:
                       print '   - no dry run output for delete_unique_column() due to dynamic DDL, sorry'
                   return
               constraints = list(self._constraints_affecting_columns(table_name, columns))
               if not constraints:
                   raise ValueError("Cannot find a UNIQUE constraint on table %s, columns %r" % (table_name, columns))
               for constraint in constraints:
                   self.execute(self.delete_unique_sql % (
                       self.quote_name(table_name),
                       self.quote_name(constraint),
                   ))
           def column_sql(self, table_name, field_name, field, tablespace='', with_name=True, field_prepared=False):
               """
               Creates the SQL snippet for a column. Used by add_column and add_table.
               """
               # If the field hasn't already been told its attribute name, do so.
               if not field_prepared:
                   field.set_attributes_from_name(field_name)
               # hook for the field to do any resolution prior to it's attributes being queried
               if hasattr(field, 'south_init'):
                   field.south_init()
               # Possible hook to fiddle with the fields (e.g. defaults & TEXT on MySQL)
               field = self._field_sanity(field)
               try:
                   sql = field.db_type(connection=self._get_connection())
               except TypeError:
                   sql = field.db_type()
               if sql:
                   # Some callers, like the sqlite stuff, just want the extended type.
                   if with_name:
                       field_output = [self.quote_name(field.column), sql]
                   else:
                       field_output = [sql]
                   field_output.append('%sNULL' % (not field.null and 'NOT ' or ''))
                   if field.primary_key:
                       field_output.append('PRIMARY KEY')
                   elif field.unique:
                       # Just use UNIQUE (no indexes any more, we have delete_unique)
                       field_output.append('UNIQUE')
                   tablespace = field.db_tablespace or tablespace
                   if tablespace and getattr(self._get_connection().features, "supports_tablespaces", False) and field.unique:
                       # We must specify the index tablespace inline, because we
                       # won't be generating a CREATE INDEX statement for this field.
                       field_output.append(self._get_connection().ops.tablespace_sql(tablespace, inline=True))
                   sql = ' '.join(field_output)
                   sqlparams = ()
                   # if the field is "NOT NULL" and a default value is provided, create the column with it
                   # this allows the addition of a NOT NULL field to a table with existing rows
                   if not getattr(field, '_suppress_default', False):
                       if field.has_default():
                           default = field.get_default()
                           # If the default is actually None, don't add a default term
                           if default is not None:
                               # If the default is a callable, then call it!
                               if callable(default):
                                   default = default()
                               default = field.get_db_prep_save(default, connection=self._get_connection())
                               default = self._default_value_workaround(default)
                               # Now do some very cheap quoting. TODO: Redesign return values to avoid this.
                               if isinstance(default, basestring):
                                   default = "'%s'" % default.replace("'", "''")
                               # Escape any % signs in the output (bug #317)
                               if isinstance(default, basestring):
                                   default = default.replace("%", "%%")
                               # Add it in
                               sql += " DEFAULT %s"
                               sqlparams = (default)
                       elif (not field.null and field.blank) or (field.get_default() == ''):
                           if field.empty_strings_allowed and self._get_connection().features.interprets_empty_strings_as_nulls:
                               sql += " DEFAULT ''"
                           # Error here would be nice, but doesn't seem to play fair.
                           #else:
                           #    raise ValueError("Attempting to add a non null column that isn't character based without an explicit default value.")
                   if field.rel and self.supports_foreign_keys:
                       self.add_deferred_sql(
                           self.foreign_key_sql(
                               table_name,
                               field.column,
                               field.rel.to._meta.db_table,
                               field.rel.to._meta.get_field(field.rel.field_name).column
+                          )
+                      )
               # Things like the contrib.gis module fields have this in 1.1 and below
               if hasattr(field, 'post_create_sql'):
                   for stmt in field.post_create_sql(no_style(), table_name):
                       self.add_deferred_sql(stmt)
               # In 1.2 and above, you have to ask the DatabaseCreation stuff for it.
               # This also creates normal indexes in 1.1.
               if hasattr(self._get_connection().creation, "sql_indexes_for_field"):
                   # Make a fake model to pass in, with only db_table
                   model = self.mock_model("FakeModelForGISCreation", table_name)
                   for stmt in self._get_connection().creation.sql_indexes_for_field(model, field, no_style()):
                       self.add_deferred_sql(stmt)
               if sql:
                   return sql % sqlparams
               else:
                   return None
           def _field_sanity(self, field):
               """
               Placeholder for DBMS-specific field alterations (some combos aren't valid,
               e.g. DEFAULT and TEXT on MySQL)
               """
               return field
           def _default_value_workaround(self, value):
               """
               DBMS-specific value alterations (this really works around
               missing functionality in Django backends)
               """
               if isinstance(value, bool) and not self.has_booleans:
                   return int(value)
               else:
                   return value
           def foreign_key_sql(self, from_table_name, from_column_name, to_table_name, to_column_name):
               """
               Generates a full SQL statement to add a foreign key constraint
               """
               constraint_name = '%s_refs_%s_%x' % (from_column_name, to_column_name, abs(hash((from_table_name, to_table_name))))
               return 'ALTER TABLE %s ADD CONSTRAINT %s FOREIGN KEY (%s) REFERENCES %s (%s)%s;' % (
                   self.quote_name(from_table_name),
                   self.quote_name(truncate_name(constraint_name, self._get_connection().ops.max_name_length())),
                   self.quote_name(from_column_name),
                   self.quote_name(to_table_name),
                   self.quote_name(to_column_name),
                   self._get_connection().ops.deferrable_sql()  # Django knows this
+              )
           @invalidate_table_constraints
           def delete_foreign_key(self, table_name, column):
               """
               Drop a foreign key constraint
               """
               if self.dry_run:
                   if self.debug:
                       print '   - no dry run output for delete_foreign_key() due to dynamic DDL, sorry'
                   return  # We can't look at the DB to get the constraints
               constraints = self._find_foreign_constraints(table_name, column)
               if not constraints:
                   raise ValueError("Cannot find a FOREIGN KEY constraint on table %s, column %s" % (table_name, column))
               for constraint_name in constraints:
                   self.execute(self.delete_foreign_key_sql % {
                       "table": self.quote_name(table_name),
                       "constraint": self.quote_name(constraint_name),
                   })
           drop_foreign_key = alias('delete_foreign_key')
           def _find_foreign_constraints(self, table_name, column_name=None):
               constraints = self._constraints_affecting_columns(
                                   table_name, [column_name], "FOREIGN KEY")
               primary_key_columns = self._find_primary_key_columns(table_name)
               if len(primary_key_columns) > 1:
                   # Composite primary keys cannot be referenced by a foreign key
                   return list(constraints)
               else:
                   primary_key_columns.add(column_name)
                   recursive_constraints = set(self._constraints_affecting_columns(
                                       table_name, primary_key_columns, "FOREIGN KEY"))
                   return list(recursive_constraints.union(constraints))
           def _digest(self, *args):
               """
               Use django.db.backends.creation.BaseDatabaseCreation._digest
               to create index name in Django style. An evil hack :(
               """
               if not hasattr(self, '_django_db_creation'):
                   self._django_db_creation = BaseDatabaseCreation(self._get_connection())
               return self._django_db_creation._digest(*args)
           def create_index_name(self, table_name, column_names, suffix=""):
               """
               Generate a unique name for the index
               """
               # If there is just one column in the index, use a default algorithm from Django
               if len(column_names) == 1 and not suffix:
                   return truncate_name(
                       '%s_%s' % (table_name, self._digest(column_names[0])),
                       self._get_connection().ops.max_name_length()
+                  )
               # Else generate the name for the index by South
               table_name = table_name.replace('"', '').replace('.', '_')
               index_unique_name = '_%x' % abs(hash((table_name, ','.join(column_names))))
               # If the index name is too long, truncate it
               index_name = ('%s_%s%s%s' % (table_name, column_names[0], index_unique_name, suffix)).replace('"', '').replace('.', '_')
               if len(index_name) > self.max_index_name_length:
                   part = ('_%s%s%s' % (column_names[0], index_unique_name, suffix))
                   index_name = '%s%s' % (table_name[:(self.max_index_name_length - len(part))], part)
               return index_name
           def create_index_sql(self, table_name, column_names, unique=False, db_tablespace=''):
               """
               Generates a create index statement on 'table_name' for a list of 'column_names'
               """
               if not column_names:
                   print "No column names supplied on which to create an index"
                   return ''
               connection = self._get_connection()
               if db_tablespace and connection.features.supports_tablespaces:
                   tablespace_sql = ' ' + connection.ops.tablespace_sql(db_tablespace)
               else:
                   tablespace_sql = ''
               index_name = self.create_index_name(table_name, column_names)
               return 'CREATE %sINDEX %s ON %s (%s)%s;' % (
                   unique and 'UNIQUE ' or '',
                   self.quote_name(index_name),
                   self.quote_name(table_name),
                   ','.join([self.quote_name(field) for field in column_names]),
                   tablespace_sql
+              )
           @invalidate_table_constraints
           def create_index(self, table_name, column_names, unique=False, db_tablespace=''):
               """ Executes a create index statement """
               sql = self.create_index_sql(table_name, column_names, unique, db_tablespace)
               self.execute(sql)
           @invalidate_table_constraints
           def delete_index(self, table_name, column_names, db_tablespace=''):
               """
               Deletes an index created with create_index.
               This is possible using only columns due to the deterministic
               index naming function which relies on column names.
               """
               if isinstance(column_names, (str, unicode)):
                   column_names = [column_names]
               name = self.create_index_name(table_name, column_names)
               sql = self.drop_index_string % {
                   "index_name": self.quote_name(name),
                   "table_name": self.quote_name(table_name),
+              }
               self.execute(sql)
           drop_index = alias('delete_index')
           @delete_column_constraints
           def delete_column(self, table_name, name):
               """
               Deletes the column 'column_name' from the table 'table_name'.
               """
               params = (self.quote_name(table_name), self.quote_name(name))
               self.execute(self.delete_column_string % params, [])
           drop_column = alias('delete_column')
           def rename_column(self, table_name, old, new):
               """
               Renames the column 'old' from the table 'table_name' to 'new'.
               """
               raise NotImplementedError("rename_column has no generic SQL syntax")
           @invalidate_table_constraints
           def delete_primary_key(self, table_name):
               """
               Drops the old primary key.
               """
               # Dry runs mean we can't do anything.
               if self.dry_run:
                   if self.debug:
                       print '   - no dry run output for delete_primary_key() due to dynamic DDL, sorry'
                   return
               constraints = list(self._constraints_affecting_columns(table_name, None, type="PRIMARY KEY"))
               if not constraints:
                   raise ValueError("Cannot find a PRIMARY KEY constraint on table %s" % (table_name,))
               for constraint in constraints:
                   self.execute(self.delete_primary_key_sql % {
                       "table": self.quote_name(table_name),
                       "constraint": self.quote_name(constraint),
                   })
           drop_primary_key = alias('delete_primary_key')
           @invalidate_table_constraints
           def create_primary_key(self, table_name, columns):
               """
               Creates a new primary key on the specified columns.
               """
               if not isinstance(columns, (list, tuple)):
                   columns = [columns]
               self.execute(self.create_primary_key_string % {
                   "table": self.quote_name(table_name),
                   "constraint": self.quote_name(table_name + "_pkey"),
                   "columns": ", ".join(map(self.quote_name, columns)),
               })
           def _find_primary_key_columns(self, table_name):
               """
               Find all columns of the primary key of the specified table
               """
               db_name = self._get_setting('NAME')
               primary_key_columns = set()
               for col, constraints in self.lookup_constraint(db_name, table_name):
                   for kind, cname in constraints:
                       if kind == 'PRIMARY KEY':
                           primary_key_columns.add(col.lower())
               return primary_key_columns
           def start_transaction(self):
               """
               Makes sure the following commands are inside a transaction.
               Must be followed by a (commit|rollback)_transaction call.
               """
               if self.dry_run:
                   self.pending_transactions += 1
               transaction.commit_unless_managed(using=self.db_alias)
               transaction.enter_transaction_management(using=self.db_alias)
               transaction.managed(True, using=self.db_alias)
           def commit_transaction(self):
               """
               Commits the current transaction.
               Must be preceded by a start_transaction call.
               """
               if self.dry_run:
                   return
               transaction.commit(using=self.db_alias)
               transaction.leave_transaction_management(using=self.db_alias)
           def rollback_transaction(self):
               """
               Rolls back the current transaction.
               Must be preceded by a start_transaction call.
               """
               if self.dry_run:
                   self.pending_transactions -= 1
               transaction.rollback(using=self.db_alias)
               transaction.leave_transaction_management(using=self.db_alias)
           def rollback_transactions_dry_run(self):
               """
               Rolls back all pending_transactions during this dry run.
               """
               if not self.dry_run:
                   return
               while self.pending_transactions > 0:
                   self.rollback_transaction()
               if transaction.is_dirty(using=self.db_alias):
                   # Force an exception, if we're still in a dirty transaction.
                   # This means we are missing a COMMIT/ROLLBACK.
                   transaction.leave_transaction_management(using=self.db_alias)
           def send_create_signal(self, app_label, model_names):
               self.pending_create_signals.append((app_label, model_names))
           def send_pending_create_signals(self, verbosity=0, interactive=False):
               # Group app_labels together
               signals = SortedDict()
               for (app_label, model_names) in self.pending_create_signals:
                   try:
                       signals[app_label].extend(model_names)
                   except KeyError:
                       signals[app_label] = list(model_names)
               # Send only one signal per app.
               for (app_label, model_names) in signals.iteritems():
                   self.really_send_create_signal(app_label, list(set(model_names)),
                                                  verbosity=verbosity,
                                                  interactive=interactive)
               self.pending_create_signals = []
           def really_send_create_signal(self, app_label, model_names,
                                         verbosity=0, interactive=False):
               """
               Sends a post_syncdb signal for the model specified.
               If the model is not found (perhaps it's been deleted?),
               no signal is sent.
               TODO: The behavior of django.contrib.* apps seems flawed in that
               they don't respect created_models.  Rather, they blindly execute
               over all models within the app sending the signal.  This is a
               patch we should push Django to make  For now, this should work.
               """
               if self.debug:
                   print " - Sending post_syncdb signal for %s: %s" % (app_label, model_names)
               app = models.get_app(app_label)
               if not app:
                   return
               created_models = []
               for model_name in model_names:
                   model = models.get_model(app_label, model_name)
                   if model:
                       created_models.append(model)
               if created_models:
                   if hasattr(dispatcher, "send"):
                       # Older djangos
                       dispatcher.send(signal=models.signals.post_syncdb, sender=app,
                                       app=app, created_models=created_models,
                                       verbosity=verbosity, interactive=interactive)
                   else:
                       if self._is_multidb():
                           # Django 1.2+
                           models.signals.post_syncdb.send(
                               sender=app,
                               app=app,
                               created_models=created_models,
                               verbosity=verbosity,
                               interactive=interactive,
                               db=self.db_alias,
+                          )
                       else:
                           # Django 1.1 - 1.0
                           models.signals.post_syncdb.send(
                               sender=app,
                               app=app,
                               created_models=created_models,
                               verbosity=verbosity,
                               interactive=interactive,
+                          )
           def mock_model(self, model_name, db_table, db_tablespace='',
                          pk_field_name='id', pk_field_type=models.AutoField,
                          pk_field_args=[], pk_field_kwargs={}):
               """
               Generates a MockModel class that provides enough information
               to be used by a foreign key/many-to-many relationship.
               Migrations should prefer to use these rather than actual models
               as models could get deleted over time, but these can remain in
               migration files forever.
               Depreciated.
               """
               class MockOptions(object):
                   def __init__(self):
                       self.db_table = db_table
                       self.db_tablespace = db_tablespace or settings.DEFAULT_TABLESPACE
                       self.object_name = model_name
                       self.module_name = model_name.lower()
                       if pk_field_type == models.AutoField:
                           pk_field_kwargs['primary_key'] = True
                       self.pk = pk_field_type(*pk_field_args, **pk_field_kwargs)
                       self.pk.set_attributes_from_name(pk_field_name)
                       self.abstract = False
                   def get_field_by_name(self, field_name):
                       # we only care about the pk field
                       return (self.pk, self.model, True, False)
                   def get_field(self, name):
                       # we only care about the pk field
                       return self.pk
               class MockModel(object):
                   _meta = None
               # We need to return an actual class object here, not an instance
               MockModel._meta = MockOptions()
               MockModel._meta.model = MockModel
               return MockModel
           def _db_positive_type_for_alter_column(self, klass, field):
               """
               A helper for subclasses overriding _db_type_for_alter_column:
               Remove the check constraint from the type string for PositiveInteger
               and PositiveSmallInteger fields.
               @param klass: The type of the child (required to allow this to be used when it is subclassed)
               @param field: The field to generate type for
               """
               super_result = super(klass, self)._db_type_for_alter_column(field)
               if isinstance(field, (models.PositiveSmallIntegerField, models.PositiveIntegerField)):
                   return super_result.split(" ", 1)[0]
               return super_result
           def _alter_add_positive_check(self, klass, field, name, params, sqls):
               """
               A helper for subclasses overriding _alter_add_column_mods:
               Add a check constraint verifying positivity to PositiveInteger and
               PositiveSmallInteger fields.
               """
               super(klass, self)._alter_add_column_mods(field, name, params, sqls)
               if isinstance(field, (models.PositiveSmallIntegerField, models.PositiveIntegerField)):
                   uniq_hash = abs(hash(tuple(params.values())))
                   d = dict(
                            constraint = "CK_%s_PSTV_%s" % (name, hex(uniq_hash)[2:]),
                            check = "%s >= 0" % self.quote_name(name))
                   sqls.append((self.add_check_constraint_fragment % d, []))
       # Single-level flattening of lists
       def flatten(ls):
           nl = []
           for l in ls:
               nl += l
           return nl

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root / env / lib / python2.7 / site-packages / south / db / generic.py @ d1a4905f