django1/django/db/backends/sqlite3/base.py

173 lines
6.2 KiB
Python

"""
SQLite3 backend for django. Requires pysqlite2 (http://pysqlite.org/).
"""
from django.db.backends import BaseDatabaseWrapper, BaseDatabaseOperations, util
try:
try:
from sqlite3 import dbapi2 as Database
except ImportError:
from pysqlite2 import dbapi2 as Database
except ImportError, e:
import sys
from django.core.exceptions import ImproperlyConfigured
if sys.version_info < (2, 5, 0):
module = 'pysqlite2'
else:
module = 'sqlite3'
raise ImproperlyConfigured, "Error loading %s module: %s" % (module, e)
try:
import decimal
except ImportError:
from django.utils import _decimal as decimal # for Python 2.3
DatabaseError = Database.DatabaseError
IntegrityError = Database.IntegrityError
Database.register_converter("bool", lambda s: str(s) == '1')
Database.register_converter("time", util.typecast_time)
Database.register_converter("date", util.typecast_date)
Database.register_converter("datetime", util.typecast_timestamp)
Database.register_converter("timestamp", util.typecast_timestamp)
Database.register_converter("TIMESTAMP", util.typecast_timestamp)
Database.register_converter("decimal", util.typecast_decimal)
Database.register_adapter(decimal.Decimal, util.rev_typecast_decimal)
class DatabaseOperations(BaseDatabaseOperations):
def date_extract_sql(self, lookup_type, field_name):
# sqlite doesn't support extract, so we fake it with the user-defined
# function django_extract that's registered in connect().
return 'django_extract("%s", %s)' % (lookup_type.lower(), field_name)
def date_trunc_sql(self, lookup_type, field_name):
# sqlite doesn't support DATE_TRUNC, so we fake it with a user-defined
# function django_date_trunc that's registered in connect().
return 'django_date_trunc("%s", %s)' % (lookup_type.lower(), field_name)
def drop_foreignkey_sql(self):
return ""
def pk_default_value(self):
return 'NULL'
def sql_flush(self, style, tables, sequences):
# NB: The generated SQL below is specific to SQLite
# Note: The DELETE FROM... SQL generated below works for SQLite databases
# because constraints don't exist
sql = ['%s %s %s;' % \
(style.SQL_KEYWORD('DELETE'),
style.SQL_KEYWORD('FROM'),
style.SQL_FIELD(quote_name(table))
) for table in tables]
# Note: No requirement for reset of auto-incremented indices (cf. other
# sql_flush() implementations). Just return SQL at this point
return sql
class DatabaseWrapper(BaseDatabaseWrapper):
ops = DatabaseOperations()
def _cursor(self, settings):
if self.connection is None:
kwargs = {
'database': settings.DATABASE_NAME,
'detect_types': Database.PARSE_DECLTYPES | Database.PARSE_COLNAMES,
}
kwargs.update(self.options)
self.connection = Database.connect(**kwargs)
# Register extract, date_trunc, and regexp functions.
self.connection.create_function("django_extract", 2, _sqlite_extract)
self.connection.create_function("django_date_trunc", 2, _sqlite_date_trunc)
self.connection.create_function("regexp", 2, _sqlite_regexp)
return self.connection.cursor(factory=SQLiteCursorWrapper)
def close(self):
from django.conf import settings
# If database is in memory, closing the connection destroys the
# database. To prevent accidental data loss, ignore close requests on
# an in-memory db.
if settings.DATABASE_NAME != ":memory:":
BaseDatabaseWrapper.close(self)
class SQLiteCursorWrapper(Database.Cursor):
"""
Django uses "format" style placeholders, but pysqlite2 uses "qmark" style.
This fixes it -- but note that if you want to use a literal "%s" in a query,
you'll need to use "%%s".
"""
def execute(self, query, params=()):
query = self.convert_query(query, len(params))
return Database.Cursor.execute(self, query, params)
def executemany(self, query, param_list):
query = self.convert_query(query, len(param_list[0]))
return Database.Cursor.executemany(self, query, param_list)
def convert_query(self, query, num_params):
return query % tuple("?" * num_params)
allows_group_by_ordinal = True
allows_unique_and_pk = True
autoindexes_primary_keys = True
needs_datetime_string_cast = True
needs_upper_for_iops = False
supports_constraints = False
supports_tablespaces = False
uses_case_insensitive_names = False
def quote_name(name):
if name.startswith('"') and name.endswith('"'):
return name # Quoting once is enough.
return '"%s"' % name
dictfetchone = util.dictfetchone
dictfetchmany = util.dictfetchmany
dictfetchall = util.dictfetchall
def _sqlite_extract(lookup_type, dt):
try:
dt = util.typecast_timestamp(dt)
except (ValueError, TypeError):
return None
return str(getattr(dt, lookup_type))
def _sqlite_date_trunc(lookup_type, dt):
try:
dt = util.typecast_timestamp(dt)
except (ValueError, TypeError):
return None
if lookup_type == 'year':
return "%i-01-01 00:00:00" % dt.year
elif lookup_type == 'month':
return "%i-%02i-01 00:00:00" % (dt.year, dt.month)
elif lookup_type == 'day':
return "%i-%02i-%02i 00:00:00" % (dt.year, dt.month, dt.day)
def _sqlite_regexp(re_pattern, re_string):
import re
try:
return bool(re.search(re_pattern, re_string))
except:
return False
# SQLite requires LIKE statements to include an ESCAPE clause if the value
# being escaped has a percent or underscore in it.
# See http://www.sqlite.org/lang_expr.html for an explanation.
OPERATOR_MAPPING = {
'exact': '= %s',
'iexact': "LIKE %s ESCAPE '\\'",
'contains': "LIKE %s ESCAPE '\\'",
'icontains': "LIKE %s ESCAPE '\\'",
'regex': 'REGEXP %s',
'iregex': "REGEXP '(?i)' || %s",
'gt': '> %s',
'gte': '>= %s',
'lt': '< %s',
'lte': '<= %s',
'startswith': "LIKE %s ESCAPE '\\'",
'endswith': "LIKE %s ESCAPE '\\'",
'istartswith': "LIKE %s ESCAPE '\\'",
'iendswith': "LIKE %s ESCAPE '\\'",
}