Deprecated the psycopg-based postgresql database backend.

git-svn-id: http://code.djangoproject.com/svn/django/trunk@15980 bcc190cf-cafb-0310-a4f2-bffc1f526a37

1 files changed, 212 insertions, 0 deletions

diff --git a/django/db/backends/postgresql_psycopg2/operations.py b/django/db/backends/postgresql_psycopg2/operations.py
new file mode 100644
index 0000000000..537fa45981
--- /dev/null
+++ b/django/db/backends/postgresql_psycopg2/operations.py
@@ -0,0 +1,212 @@
+import re
+
+from django.db.backends import BaseDatabaseOperations
+
+
+class DatabaseOperations(BaseDatabaseOperations):
+    def __init__(self, connection):
+        super(DatabaseOperations, self).__init__()
+        self._postgres_version = None
+        self.connection = connection
+
+    def _get_postgres_version(self):
+        if self._postgres_version is None:
+            from django.db.backends.postgresql_psycopg2.version import get_version
+            cursor = self.connection.cursor()
+            self._postgres_version = get_version(cursor)
+        return self._postgres_version
+    postgres_version = property(_get_postgres_version)
+
+    def date_extract_sql(self, lookup_type, field_name):
+        # http://www.postgresql.org/docs/8.0/static/functions-datetime.html#FUNCTIONS-DATETIME-EXTRACT
+        if lookup_type == 'week_day':
+            # For consistency across backends, we return Sunday=1, Saturday=7.
+            return "EXTRACT('dow' FROM %s) + 1" % field_name
+        else:
+            return "EXTRACT('%s' FROM %s)" % (lookup_type, field_name)
+
+    def date_interval_sql(self, sql, connector, timedelta):
+        """
+        implements the interval functionality for expressions
+        format for Postgres:
+            (datefield + interval '3 days 200 seconds 5 microseconds')
+        """
+        modifiers = []
+        if timedelta.days:
+            modifiers.append(u'%s days' % timedelta.days)
+        if timedelta.seconds:
+            modifiers.append(u'%s seconds' % timedelta.seconds)
+        if timedelta.microseconds:
+            modifiers.append(u'%s microseconds' % timedelta.microseconds)
+        mods = u' '.join(modifiers)
+        conn = u' %s ' % connector
+        return u'(%s)' % conn.join([sql, u'interval \'%s\'' % mods])
+
+    def date_trunc_sql(self, lookup_type, field_name):
+        # http://www.postgresql.org/docs/8.0/static/functions-datetime.html#FUNCTIONS-DATETIME-TRUNC
+        return "DATE_TRUNC('%s', %s)" % (lookup_type, field_name)
+
+    def deferrable_sql(self):
+        return " DEFERRABLE INITIALLY DEFERRED"
+
+    def lookup_cast(self, lookup_type):
+        lookup = '%s'
+
+        # Cast text lookups to text to allow things like filter(x__contains=4)
+        if lookup_type in ('iexact', 'contains', 'icontains', 'startswith',
+                           'istartswith', 'endswith', 'iendswith'):
+            lookup = "%s::text"
+
+        # Use UPPER(x) for case-insensitive lookups; it's faster.
+        if lookup_type in ('iexact', 'icontains', 'istartswith', 'iendswith'):
+            lookup = 'UPPER(%s)' % lookup
+
+        return lookup
+
+    def field_cast_sql(self, db_type):
+        if db_type == 'inet':
+            return 'HOST(%s)'
+        return '%s'
+
+    def last_insert_id(self, cursor, table_name, pk_name):
+        # Use pg_get_serial_sequence to get the underlying sequence name
+        # from the table name and column name (available since PostgreSQL 8)
+        cursor.execute("SELECT CURRVAL(pg_get_serial_sequence('%s','%s'))" % (
+            self.quote_name(table_name), pk_name))
+        return cursor.fetchone()[0]
+
+    def no_limit_value(self):
+        return None
+
+    def quote_name(self, name):
+        if name.startswith('"') and name.endswith('"'):
+            return name # Quoting once is enough.
+        return '"%s"' % name
+
+    def sql_flush(self, style, tables, sequences):
+        if tables:
+            if self.postgres_version[0:2] >= (8,1):
+                # Postgres 8.1+ can do 'TRUNCATE x, y, z...;'. In fact, it *has to*
+                # in order to be able to truncate tables referenced by a foreign
+                # key in any other table. The result is a single SQL TRUNCATE
+                # statement.
+                sql = ['%s %s;' % \
+                    (style.SQL_KEYWORD('TRUNCATE'),
+                     style.SQL_FIELD(', '.join([self.quote_name(table) for table in tables]))
+                )]
+            else:
+                # Older versions of Postgres can't do TRUNCATE in a single call, so
+                # they must use a simple delete.
+                sql = ['%s %s %s;' % \
+                        (style.SQL_KEYWORD('DELETE'),
+                         style.SQL_KEYWORD('FROM'),
+                         style.SQL_FIELD(self.quote_name(table))
+                         ) for table in tables]
+
+            # 'ALTER SEQUENCE sequence_name RESTART WITH 1;'... style SQL statements
+            # to reset sequence indices
+            for sequence_info in sequences:
+                table_name = sequence_info['table']
+                column_name = sequence_info['column']
+                if not (column_name and len(column_name) > 0):
+                    # This will be the case if it's an m2m using an autogenerated
+                    # intermediate table (see BaseDatabaseIntrospection.sequence_list)
+                    column_name = 'id'
+                sql.append("%s setval(pg_get_serial_sequence('%s','%s'), 1, false);" % \
+                    (style.SQL_KEYWORD('SELECT'),
+                    style.SQL_TABLE(self.quote_name(table_name)),
+                    style.SQL_FIELD(column_name))
+                )
+            return sql
+        else:
+            return []
+
+    def sequence_reset_sql(self, style, model_list):
+        from django.db import models
+        output = []
+        qn = self.quote_name
+        for model in model_list:
+            # Use `coalesce` to set the sequence for each model to the max pk value if there are records,
+            # or 1 if there are none. Set the `is_called` property (the third argument to `setval`) to true
+            # if there are records (as the max pk value is already in use), otherwise set it to false.
+            # Use pg_get_serial_sequence to get the underlying sequence name from the table name
+            # and column name (available since PostgreSQL 8)
+
+            for f in model._meta.local_fields:
+                if isinstance(f, models.AutoField):
+                    output.append("%s setval(pg_get_serial_sequence('%s','%s'), coalesce(max(%s), 1), max(%s) %s null) %s %s;" % \
+                        (style.SQL_KEYWORD('SELECT'),
+                        style.SQL_TABLE(qn(model._meta.db_table)),
+                        style.SQL_FIELD(f.column),
+                        style.SQL_FIELD(qn(f.column)),
+                        style.SQL_FIELD(qn(f.column)),
+                        style.SQL_KEYWORD('IS NOT'),
+                        style.SQL_KEYWORD('FROM'),
+                        style.SQL_TABLE(qn(model._meta.db_table))))
+                    break # Only one AutoField is allowed per model, so don't bother continuing.
+            for f in model._meta.many_to_many:
+                if not f.rel.through:
+                    output.append("%s setval(pg_get_serial_sequence('%s','%s'), coalesce(max(%s), 1), max(%s) %s null) %s %s;" % \
+                        (style.SQL_KEYWORD('SELECT'),
+                        style.SQL_TABLE(qn(f.m2m_db_table())),
+                        style.SQL_FIELD('id'),
+                        style.SQL_FIELD(qn('id')),
+                        style.SQL_FIELD(qn('id')),
+                        style.SQL_KEYWORD('IS NOT'),
+                        style.SQL_KEYWORD('FROM'),
+                        style.SQL_TABLE(qn(f.m2m_db_table()))))
+        return output
+
+    def savepoint_create_sql(self, sid):
+        return "SAVEPOINT %s" % sid
+
+    def savepoint_commit_sql(self, sid):
+        return "RELEASE SAVEPOINT %s" % sid
+
+    def savepoint_rollback_sql(self, sid):
+        return "ROLLBACK TO SAVEPOINT %s" % sid
+
+    def prep_for_iexact_query(self, x):
+        return x
+
+    def check_aggregate_support(self, aggregate):
+        """Check that the backend fully supports the provided aggregate.
+
+        The population and sample statistics (STDDEV_POP, STDDEV_SAMP,
+        VAR_POP, VAR_SAMP) were first implemented in Postgres 8.2.
+
+        The implementation of population statistics (STDDEV_POP and VAR_POP)
+        under Postgres 8.2 - 8.2.4 is known to be faulty. Raise
+        NotImplementedError if this is the database in use.
+        """
+        if aggregate.sql_function in ('STDDEV_POP', 'STDDEV_SAMP', 'VAR_POP', 'VAR_SAMP'):
+            if self.postgres_version[0:2] < (8,2):
+                raise NotImplementedError('PostgreSQL does not support %s prior to version 8.2. Please upgrade your version of PostgreSQL.' % aggregate.sql_function)
+
+        if aggregate.sql_function in ('STDDEV_POP', 'VAR_POP'):
+            if self.postgres_version[0:2] == (8,2):
+                if self.postgres_version[2] is None or self.postgres_version[2] <= 4:
+                    raise NotImplementedError('PostgreSQL 8.2 to 8.2.4 is known to have a faulty implementation of %s. Please upgrade your version of PostgreSQL.' % aggregate.sql_function)
+
+    def max_name_length(self):
+        """
+        Returns the maximum length of an identifier.
+
+        Note that 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 simply returns 63, but can easily be overridden by a
+        custom database backend that inherits most of its behavior from this one.
+        """
+
+        return 63
+
+    def last_executed_query(self, cursor, sql, params):
+        # With psycopg2, cursor objects have a "query" attribute that is the
+        # exact query sent to the database. See docs here:
+        # http://www.initd.org/tracker/psycopg/wiki/psycopg2_documentation#postgresql-status-message-and-executed-query
+        return cursor.query
+
+    def return_insert_id(self):
+        return "RETURNING %s", ()