242 lines
8.8 KiB
Python
242 lines
8.8 KiB
Python
"""
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PostgreSQL database backend for Django.
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Requires psycopg 1: http://initd.org/projects/psycopg1
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"""
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from django.db.backends import util
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try:
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import psycopg as Database
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except ImportError, e:
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from django.core.exceptions import ImproperlyConfigured
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raise ImproperlyConfigured, "Error loading psycopg module: %s" % e
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DatabaseError = Database.DatabaseError
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try:
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# Only exists in Python 2.4+
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from threading import local
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except ImportError:
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# Import copy of _thread_local.py from Python 2.4
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from django.utils._threading_local import local
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def smart_basestring(s, charset):
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if isinstance(s, unicode):
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return s.encode(charset)
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return s
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class UnicodeCursorWrapper(object):
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"""
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A thin wrapper around psycopg cursors that allows them to accept Unicode
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strings as params.
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This is necessary because psycopg doesn't apply any DB quoting to
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parameters that are Unicode strings. If a param is Unicode, this will
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convert it to a bytestring using DEFAULT_CHARSET before passing it to
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psycopg.
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"""
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def __init__(self, cursor, charset):
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self.cursor = cursor
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self.charset = charset
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def execute(self, sql, params=()):
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return self.cursor.execute(sql, [smart_basestring(p, self.charset) for p in params])
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def executemany(self, sql, param_list):
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new_param_list = [tuple([smart_basestring(p, self.charset) for p in params]) for params in param_list]
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return self.cursor.executemany(sql, new_param_list)
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def __getattr__(self, attr):
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if self.__dict__.has_key(attr):
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return self.__dict__[attr]
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else:
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return getattr(self.cursor, attr)
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postgres_version = None
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class DatabaseWrapper(local):
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def __init__(self, **kwargs):
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self.connection = None
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self.queries = []
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self.options = kwargs
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def cursor(self):
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from django.conf import settings
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set_tz = False
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if self.connection is None:
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set_tz = True
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if settings.DATABASE_NAME == '':
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from django.core.exceptions import ImproperlyConfigured
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raise ImproperlyConfigured, "You need to specify DATABASE_NAME in your Django settings file."
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conn_string = "dbname=%s" % settings.DATABASE_NAME
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if settings.DATABASE_USER:
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conn_string = "user=%s %s" % (settings.DATABASE_USER, conn_string)
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if settings.DATABASE_PASSWORD:
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conn_string += " password='%s'" % settings.DATABASE_PASSWORD
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if settings.DATABASE_HOST:
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conn_string += " host=%s" % settings.DATABASE_HOST
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if settings.DATABASE_PORT:
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conn_string += " port=%s" % settings.DATABASE_PORT
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self.connection = Database.connect(conn_string, **self.options)
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self.connection.set_isolation_level(1) # make transactions transparent to all cursors
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cursor = self.connection.cursor()
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if set_tz:
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cursor.execute("SET TIME ZONE %s", [settings.TIME_ZONE])
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cursor = UnicodeCursorWrapper(cursor, settings.DEFAULT_CHARSET)
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global postgres_version
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if not postgres_version:
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cursor.execute("SELECT version()")
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postgres_version = [int(val) for val in cursor.fetchone()[0].split()[1].split('.')]
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if settings.DEBUG:
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return util.CursorDebugWrapper(cursor, self)
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return cursor
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def _commit(self):
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if self.connection is not None:
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return self.connection.commit()
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def _rollback(self):
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if self.connection is not None:
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return self.connection.rollback()
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def close(self):
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if self.connection is not None:
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self.connection.close()
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self.connection = None
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supports_constraints = True
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def quote_name(name):
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if name.startswith('"') and name.endswith('"'):
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return name # Quoting once is enough.
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return '"%s"' % name
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def dictfetchone(cursor):
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"Returns a row from the cursor as a dict"
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return cursor.dictfetchone()
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def dictfetchmany(cursor, number):
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"Returns a certain number of rows from a cursor as a dict"
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return cursor.dictfetchmany(number)
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def dictfetchall(cursor):
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"Returns all rows from a cursor as a dict"
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return cursor.dictfetchall()
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def get_last_insert_id(cursor, table_name, pk_name):
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cursor.execute("SELECT CURRVAL('\"%s_%s_seq\"')" % (table_name, pk_name))
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return cursor.fetchone()[0]
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def get_date_extract_sql(lookup_type, table_name):
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# lookup_type is 'year', 'month', 'day'
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# http://www.postgresql.org/docs/8.0/static/functions-datetime.html#FUNCTIONS-DATETIME-EXTRACT
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return "EXTRACT('%s' FROM %s)" % (lookup_type, table_name)
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def get_date_trunc_sql(lookup_type, field_name):
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# lookup_type is 'year', 'month', 'day'
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# http://www.postgresql.org/docs/8.0/static/functions-datetime.html#FUNCTIONS-DATETIME-TRUNC
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return "DATE_TRUNC('%s', %s)" % (lookup_type, field_name)
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def get_limit_offset_sql(limit, offset=None):
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sql = "LIMIT %s" % limit
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if offset and offset != 0:
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sql += " OFFSET %s" % offset
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return sql
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def get_random_function_sql():
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return "RANDOM()"
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def get_deferrable_sql():
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return " DEFERRABLE INITIALLY DEFERRED"
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def get_fulltext_search_sql(field_name):
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raise NotImplementedError
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def get_drop_foreignkey_sql():
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return "DROP CONSTRAINT"
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def get_pk_default_value():
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return "DEFAULT"
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def get_sql_flush(style, tables, sequences):
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"""Return a list of SQL statements required to remove all data from
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all tables in the database (without actually removing the tables
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themselves) and put the database in an empty 'initial' state
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"""
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if tables:
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if postgres_version[0] >= 8 and postgres_version[1] >= 1:
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# Postgres 8.1+ can do 'TRUNCATE x, y, z...;'. In fact, it *has to* in order to be able to
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# truncate tables referenced by a foreign key in any other table. The result is a
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# single SQL TRUNCATE statement.
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sql = ['%s %s;' % \
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(style.SQL_KEYWORD('TRUNCATE'),
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style.SQL_FIELD(', '.join([quote_name(table) for table in tables]))
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)]
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else:
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# Older versions of Postgres can't do TRUNCATE in a single call, so they must use
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# a simple delete.
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sql = ['%s %s %s;' % \
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(style.SQL_KEYWORD('DELETE'),
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style.SQL_KEYWORD('FROM'),
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style.SQL_FIELD(quote_name(table))
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) for table in tables]
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# 'ALTER SEQUENCE sequence_name RESTART WITH 1;'... style SQL statements
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# to reset sequence indices
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for sequence_info in sequences:
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table_name = sequence_info['table']
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column_name = sequence_info['column']
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if column_name and len(column_name)>0:
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# sequence name in this case will be <table>_<column>_seq
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sql.append("%s %s %s %s %s %s;" % \
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(style.SQL_KEYWORD('ALTER'),
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style.SQL_KEYWORD('SEQUENCE'),
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style.SQL_FIELD('%s_%s_seq' % (table_name, column_name)),
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style.SQL_KEYWORD('RESTART'),
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style.SQL_KEYWORD('WITH'),
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style.SQL_FIELD('1')
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)
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)
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else:
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# sequence name in this case will be <table>_id_seq
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sql.append("%s %s %s %s %s %s;" % \
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(style.SQL_KEYWORD('ALTER'),
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style.SQL_KEYWORD('SEQUENCE'),
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style.SQL_FIELD('%s_id_seq' % table_name),
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style.SQL_KEYWORD('RESTART'),
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style.SQL_KEYWORD('WITH'),
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style.SQL_FIELD('1')
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)
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)
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return sql
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else:
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return []
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# Register these custom typecasts, because Django expects dates/times to be
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# in Python's native (standard-library) datetime/time format, whereas psycopg
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# use mx.DateTime by default.
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try:
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Database.register_type(Database.new_type((1082,), "DATE", util.typecast_date))
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except AttributeError:
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raise Exception, "You appear to be using psycopg version 2. Set your DATABASE_ENGINE to 'postgresql_psycopg2' instead of 'postgresql'."
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Database.register_type(Database.new_type((1083,1266), "TIME", util.typecast_time))
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Database.register_type(Database.new_type((1114,1184), "TIMESTAMP", util.typecast_timestamp))
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Database.register_type(Database.new_type((16,), "BOOLEAN", util.typecast_boolean))
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OPERATOR_MAPPING = {
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'exact': '= %s',
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'iexact': 'ILIKE %s',
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'contains': 'LIKE %s',
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'icontains': 'ILIKE %s',
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'gt': '> %s',
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'gte': '>= %s',
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'lt': '< %s',
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'lte': '<= %s',
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'startswith': 'LIKE %s',
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'endswith': 'LIKE %s',
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'istartswith': 'ILIKE %s',
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'iendswith': 'ILIKE %s',
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}
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