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"""
PostgreSQL database backend for Django.
Requires psycopg 1: http://initd.org/projects/psycopg1
"""
from django.core.db import base, typecasts
import psycopg as Database
DatabaseError = Database.DatabaseError
class DatabaseWrapper:
def __init__(self):
self.connection = None
self.queries = []
def cursor(self):
from django.conf.settings import DATABASE_USER, DATABASE_NAME, DATABASE_HOST, DATABASE_PORT, DATABASE_PASSWORD, DEBUG, TIME_ZONE
if self.connection is None:
if DATABASE_NAME == '':
from django.core.exceptions import ImproperlyConfigured
raise ImproperlyConfigured, "You need to specify DATABASE_NAME in your Django settings file."
conn_string = "dbname=%s" % DATABASE_NAME
if DATABASE_USER:
conn_string = "user=%s %s" % (DATABASE_USER, conn_string)
if DATABASE_PASSWORD:
conn_string += " password=%s" % DATABASE_PASSWORD
if DATABASE_HOST:
conn_string += " host=%s" % DATABASE_HOST
if DATABASE_PORT:
conn_string += " port=%s" % DATABASE_PORT
self.connection = Database.connect(conn_string)
self.connection.set_isolation_level(1) # make transactions transparent to all cursors
cursor = self.connection.cursor()
cursor.execute("SET TIME ZONE %s", [TIME_ZONE])
if DEBUG:
return base.CursorDebugWrapper(cursor, self)
return cursor
def commit(self):
return self.connection.commit()
def rollback(self):
if self.connection:
return self.connection.rollback()
def close(self):
if self.connection is not None:
self.connection.close()
self.connection = None
def quote_name(self, name):
if name.startswith('"') and name.endswith('"'):
return name # Quoting once is enough.
return '"%s"' % name
def dictfetchone(cursor):
"Returns a row from the cursor as a dict"
return cursor.dictfetchone()
def dictfetchmany(cursor, number):
"Returns a certain number of rows from a cursor as a dict"
return cursor.dictfetchmany(number)
def dictfetchall(cursor):
"Returns all rows from a cursor as a dict"
return cursor.dictfetchall()
def get_last_insert_id(cursor, table_name, pk_name):
cursor.execute("SELECT CURRVAL('%s_%s_seq')" % (table_name, pk_name))
return cursor.fetchone()[0]
def get_date_extract_sql(lookup_type, table_name):
# lookup_type is 'year', 'month', 'day'
# http://www.postgresql.org/docs/8.0/static/functions-datetime.html#FUNCTIONS-DATETIME-EXTRACT
return "EXTRACT('%s' FROM %s)" % (lookup_type, table_name)
def get_date_trunc_sql(lookup_type, field_name):
# lookup_type is 'year', 'month', 'day'
# http://www.postgresql.org/docs/8.0/static/functions-datetime.html#FUNCTIONS-DATETIME-TRUNC
return "DATE_TRUNC('%s', %s)" % (lookup_type, field_name)
def get_limit_offset_sql(limit, offset=None):
sql = "LIMIT %s" % limit
if offset and offset != 0:
sql += " OFFSET %s" % offset
return sql
def get_random_function_sql():
return "RANDOM()"
def get_table_list(cursor):
"Returns a list of table names in the current database."
cursor.execute("""
SELECT c.relname
FROM pg_catalog.pg_class c
LEFT JOIN pg_catalog.pg_namespace n ON n.oid = c.relnamespace
WHERE c.relkind IN ('r', 'v', '')
AND n.nspname NOT IN ('pg_catalog', 'pg_toast')
AND pg_catalog.pg_table_is_visible(c.oid)""")
return [row[0] for row in cursor.fetchall()]
def get_relations(cursor, table_name):
"""
Returns a dictionary of {field_index: (field_index_other_table, other_table)}
representing all relationships to the given table. Indexes are 0-based.
"""
cursor.execute("""
SELECT con.conkey, con.confkey, c2.relname
FROM pg_constraint con, pg_class c1, pg_class c2
WHERE c1.oid = con.conrelid
AND c2.oid = con.confrelid
AND c1.relname = %s
AND con.contype = 'f'""", [table_name])
relations = {}
for row in cursor.fetchall():
try:
# row[0] and row[1] are like "{2}", so strip the curly braces.
relations[int(row[0][1:-1]) - 1] = (int(row[1][1:-1]) - 1, row[2])
except ValueError:
continue
return relations
# Register these custom typecasts, because Django expects dates/times to be
# in Python's native (standard-library) datetime/time format, whereas psycopg
# use mx.DateTime by default.
try:
Database.register_type(Database.new_type((1082,), "DATE", typecasts.typecast_date))
except AttributeError:
raise Exception, "You appear to be using psycopg version 2, which isn't supported yet, because it's still in beta. Use psycopg version 1 instead: http://initd.org/projects/psycopg1"
Database.register_type(Database.new_type((1083,1266), "TIME", typecasts.typecast_time))
Database.register_type(Database.new_type((1114,1184), "TIMESTAMP", typecasts.typecast_timestamp))
Database.register_type(Database.new_type((16,), "BOOLEAN", typecasts.typecast_boolean))
OPERATOR_MAPPING = {
'exact': '=',
'iexact': 'ILIKE',
'contains': 'LIKE',
'icontains': 'ILIKE',
'ne': '!=',
'gt': '>',
'gte': '>=',
'lt': '<',
'lte': '<=',
'startswith': 'LIKE',
'endswith': 'LIKE',
'istartswith': 'ILIKE',
'iendswith': 'ILIKE',
}
# This dictionary maps Field objects to their associated PostgreSQL column
# types, as strings. Column-type strings can contain format strings; they'll
# be interpolated against the values of Field.__dict__ before being output.
# If a column type is set to None, it won't be included in the output.
DATA_TYPES = {
'AutoField': 'serial',
'BooleanField': 'boolean',
'CharField': 'varchar(%(maxlength)s)',
'CommaSeparatedIntegerField': 'varchar(%(maxlength)s)',
'DateField': 'date',
'DateTimeField': 'timestamp with time zone',
'EmailField': 'varchar(75)',
'FileField': 'varchar(100)',
'FilePathField': 'varchar(100)',
'FloatField': 'numeric(%(max_digits)s, %(decimal_places)s)',
'ImageField': 'varchar(100)',
'IntegerField': 'integer',
'IPAddressField': 'inet',
'ManyToManyField': None,
'NullBooleanField': 'boolean',
'OneToOneField': 'integer',
'PhoneNumberField': 'varchar(20)',
'PositiveIntegerField': 'integer CHECK (%(name)s >= 0)',
'PositiveSmallIntegerField': 'smallint CHECK (%(name)s >= 0)',
'SlugField': 'varchar(50)',
'SmallIntegerField': 'smallint',
'TextField': 'text',
'TimeField': 'time',
'URLField': 'varchar(200)',
'USStateField': 'varchar(2)',
}
# Maps type codes to Django Field types.
DATA_TYPES_REVERSE = {
16: 'BooleanField',
21: 'SmallIntegerField',
23: 'IntegerField',
25: 'TextField',
869: 'IPAddressField',
1043: 'CharField',
1082: 'DateField',
1083: 'TimeField',
1114: 'DateTimeField',
1184: 'DateTimeField',
1266: 'TimeField',
1700: 'FloatField',
}
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