398 lines
17 KiB
Python
398 lines
17 KiB
Python
"""
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SQLite3 backend for django.
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Works with either the pysqlite2 module or the sqlite3 module in the
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standard library.
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"""
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import datetime
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import decimal
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import warnings
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import re
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import sys
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from django.db import utils
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from django.db.backends import *
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from django.db.backends.signals import connection_created
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from django.db.backends.sqlite3.client import DatabaseClient
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from django.db.backends.sqlite3.creation import DatabaseCreation
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from django.db.backends.sqlite3.introspection import DatabaseIntrospection
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from django.utils.dateparse import parse_date, parse_datetime, parse_time
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from django.utils.safestring import SafeString
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from django.utils import timezone
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try:
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try:
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from pysqlite2 import dbapi2 as Database
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except ImportError, e1:
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from sqlite3 import dbapi2 as Database
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except ImportError, exc:
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from django.core.exceptions import ImproperlyConfigured
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raise ImproperlyConfigured("Error loading either pysqlite2 or sqlite3 modules (tried in that order): %s" % exc)
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DatabaseError = Database.DatabaseError
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IntegrityError = Database.IntegrityError
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def parse_datetime_with_timezone_support(value):
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dt = parse_datetime(value)
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# Confirm that dt is naive before overwriting its tzinfo.
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if dt is not None and settings.USE_TZ and timezone.is_naive(dt):
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dt = dt.replace(tzinfo=timezone.utc)
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return dt
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def adapt_datetime_with_timezone_support(value):
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# Equivalent to DateTimeField.get_db_prep_value. Used only by raw SQL.
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if settings.USE_TZ:
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if timezone.is_naive(value):
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warnings.warn(u"SQLite received a naive datetime (%s)"
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u" while time zone support is active." % value,
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RuntimeWarning)
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default_timezone = timezone.get_default_timezone()
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value = timezone.make_aware(value, default_timezone)
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value = value.astimezone(timezone.utc).replace(tzinfo=None)
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return value.isoformat(" ")
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Database.register_converter("bool", lambda s: str(s) == '1')
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Database.register_converter("time", parse_time)
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Database.register_converter("date", parse_date)
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Database.register_converter("datetime", parse_datetime_with_timezone_support)
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Database.register_converter("timestamp", parse_datetime_with_timezone_support)
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Database.register_converter("TIMESTAMP", parse_datetime_with_timezone_support)
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Database.register_converter("decimal", util.typecast_decimal)
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Database.register_adapter(datetime.datetime, adapt_datetime_with_timezone_support)
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Database.register_adapter(decimal.Decimal, util.rev_typecast_decimal)
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if Database.version_info >= (2, 4, 1):
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# Starting in 2.4.1, the str type is not accepted anymore, therefore,
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# we convert all str objects to Unicode
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# As registering a adapter for a primitive type causes a small
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# slow-down, this adapter is only registered for sqlite3 versions
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# needing it (Python 2.6 and up).
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Database.register_adapter(str, lambda s: s.decode('utf-8'))
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Database.register_adapter(SafeString, lambda s: s.decode('utf-8'))
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class DatabaseFeatures(BaseDatabaseFeatures):
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# SQLite cannot handle us only partially reading from a cursor's result set
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# and then writing the same rows to the database in another cursor. This
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# setting ensures we always read result sets fully into memory all in one
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# go.
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can_use_chunked_reads = False
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test_db_allows_multiple_connections = False
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supports_unspecified_pk = True
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supports_timezones = False
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supports_1000_query_parameters = False
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supports_mixed_date_datetime_comparisons = False
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has_bulk_insert = True
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can_combine_inserts_with_and_without_auto_increment_pk = True
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def _supports_stddev(self):
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"""Confirm support for STDDEV and related stats functions
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SQLite supports STDDEV as an extension package; so
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connection.ops.check_aggregate_support() can't unilaterally
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rule out support for STDDEV. We need to manually check
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whether the call works.
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"""
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cursor = self.connection.cursor()
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cursor.execute('CREATE TABLE STDDEV_TEST (X INT)')
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try:
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cursor.execute('SELECT STDDEV(*) FROM STDDEV_TEST')
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has_support = True
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except utils.DatabaseError:
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has_support = False
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cursor.execute('DROP TABLE STDDEV_TEST')
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return has_support
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class DatabaseOperations(BaseDatabaseOperations):
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def date_extract_sql(self, lookup_type, field_name):
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# sqlite doesn't support extract, so we fake it with the user-defined
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# function django_extract that's registered in connect(). Note that
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# single quotes are used because this is a string (and could otherwise
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# cause a collision with a field name).
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return "django_extract('%s', %s)" % (lookup_type.lower(), field_name)
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def date_interval_sql(self, sql, connector, timedelta):
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# It would be more straightforward if we could use the sqlite strftime
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# function, but it does not allow for keeping six digits of fractional
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# second information, nor does it allow for formatting date and datetime
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# values differently. So instead we register our own function that
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# formats the datetime combined with the delta in a manner suitable
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# for comparisons.
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return u'django_format_dtdelta(%s, "%s", "%d", "%d", "%d")' % (sql,
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connector, timedelta.days, timedelta.seconds, timedelta.microseconds)
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def date_trunc_sql(self, lookup_type, field_name):
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# sqlite doesn't support DATE_TRUNC, so we fake it with a user-defined
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# function django_date_trunc that's registered in connect(). Note that
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# single quotes are used because this is a string (and could otherwise
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# cause a collision with a field name).
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return "django_date_trunc('%s', %s)" % (lookup_type.lower(), field_name)
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def drop_foreignkey_sql(self):
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return ""
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def pk_default_value(self):
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return "NULL"
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def quote_name(self, 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 no_limit_value(self):
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return -1
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def sql_flush(self, style, tables, sequences):
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# NB: The generated SQL below is specific to SQLite
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# Note: The DELETE FROM... SQL generated below works for SQLite databases
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# because constraints don't exist
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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(self.quote_name(table))
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) for table in tables]
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# Note: No requirement for reset of auto-incremented indices (cf. other
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# sql_flush() implementations). Just return SQL at this point
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return sql
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def value_to_db_datetime(self, value):
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if value is None:
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return None
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# SQLite doesn't support tz-aware datetimes
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if timezone.is_aware(value):
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if settings.USE_TZ:
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value = value.astimezone(timezone.utc).replace(tzinfo=None)
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else:
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raise ValueError("SQLite backend does not support timezone-aware datetimes when USE_TZ is False.")
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return unicode(value)
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def value_to_db_time(self, value):
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if value is None:
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return None
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# SQLite doesn't support tz-aware datetimes
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if timezone.is_aware(value):
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raise ValueError("SQLite backend does not support timezone-aware times.")
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return unicode(value)
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def year_lookup_bounds(self, value):
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first = '%s-01-01'
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second = '%s-12-31 23:59:59.999999'
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return [first % value, second % value]
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def convert_values(self, value, field):
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"""SQLite returns floats when it should be returning decimals,
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and gets dates and datetimes wrong.
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For consistency with other backends, coerce when required.
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"""
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internal_type = field.get_internal_type()
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if internal_type == 'DecimalField':
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return util.typecast_decimal(field.format_number(value))
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elif internal_type and internal_type.endswith('IntegerField') or internal_type == 'AutoField':
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return int(value)
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elif internal_type == 'DateField':
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return parse_date(value)
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elif internal_type == 'DateTimeField':
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return parse_datetime_with_timezone_support(value)
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elif internal_type == 'TimeField':
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return parse_time(value)
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# No field, or the field isn't known to be a decimal or integer
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return value
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def bulk_insert_sql(self, fields, num_values):
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res = []
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res.append("SELECT %s" % ", ".join(
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"%%s AS %s" % self.quote_name(f.column) for f in fields
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))
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res.extend(["UNION SELECT %s" % ", ".join(["%s"] * len(fields))] * (num_values - 1))
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return " ".join(res)
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class DatabaseWrapper(BaseDatabaseWrapper):
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vendor = 'sqlite'
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# SQLite requires LIKE statements to include an ESCAPE clause if the value
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# being escaped has a percent or underscore in it.
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# See http://www.sqlite.org/lang_expr.html for an explanation.
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operators = {
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'exact': '= %s',
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'iexact': "LIKE %s ESCAPE '\\'",
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'contains': "LIKE %s ESCAPE '\\'",
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'icontains': "LIKE %s ESCAPE '\\'",
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'regex': 'REGEXP %s',
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'iregex': "REGEXP '(?i)' || %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 ESCAPE '\\'",
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'endswith': "LIKE %s ESCAPE '\\'",
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'istartswith': "LIKE %s ESCAPE '\\'",
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'iendswith': "LIKE %s ESCAPE '\\'",
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}
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def __init__(self, *args, **kwargs):
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super(DatabaseWrapper, self).__init__(*args, **kwargs)
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self.features = DatabaseFeatures(self)
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self.ops = DatabaseOperations(self)
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self.client = DatabaseClient(self)
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self.creation = DatabaseCreation(self)
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self.introspection = DatabaseIntrospection(self)
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self.validation = BaseDatabaseValidation(self)
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def _sqlite_create_connection(self):
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settings_dict = self.settings_dict
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if not settings_dict['NAME']:
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from django.core.exceptions import ImproperlyConfigured
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raise ImproperlyConfigured("Please fill out the database NAME in the settings module before using the database.")
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kwargs = {
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'database': settings_dict['NAME'],
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'detect_types': Database.PARSE_DECLTYPES | Database.PARSE_COLNAMES,
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}
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kwargs.update(settings_dict['OPTIONS'])
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# Always allow the underlying SQLite connection to be shareable
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# between multiple threads. The safe-guarding will be handled at a
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# higher level by the `BaseDatabaseWrapper.allow_thread_sharing`
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# property. This is necessary as the shareability is disabled by
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# default in pysqlite and it cannot be changed once a connection is
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# opened.
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if 'check_same_thread' in kwargs and kwargs['check_same_thread']:
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warnings.warn(
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'The `check_same_thread` option was provided and set to '
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'True. It will be overriden with False. Use the '
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'`DatabaseWrapper.allow_thread_sharing` property instead '
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'for controlling thread shareability.',
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RuntimeWarning
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)
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kwargs.update({'check_same_thread': False})
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self.connection = Database.connect(**kwargs)
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# Register extract, date_trunc, and regexp functions.
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self.connection.create_function("django_extract", 2, _sqlite_extract)
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self.connection.create_function("django_date_trunc", 2, _sqlite_date_trunc)
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self.connection.create_function("regexp", 2, _sqlite_regexp)
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self.connection.create_function("django_format_dtdelta", 5, _sqlite_format_dtdelta)
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connection_created.send(sender=self.__class__, connection=self)
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def _cursor(self):
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if self.connection is None:
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self._sqlite_create_connection()
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return self.connection.cursor(factory=SQLiteCursorWrapper)
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def check_constraints(self, table_names=None):
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"""
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Checks each table name in `table_names` for rows with invalid foreign key references. This method is
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intended to be used in conjunction with `disable_constraint_checking()` and `enable_constraint_checking()`, to
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determine if rows with invalid references were entered while constraint checks were off.
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Raises an IntegrityError on the first invalid foreign key reference encountered (if any) and provides
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detailed information about the invalid reference in the error message.
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Backends can override this method if they can more directly apply constraint checking (e.g. via "SET CONSTRAINTS
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ALL IMMEDIATE")
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"""
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cursor = self.cursor()
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if table_names is None:
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table_names = self.introspection.get_table_list(cursor)
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for table_name in table_names:
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primary_key_column_name = self.introspection.get_primary_key_column(cursor, table_name)
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if not primary_key_column_name:
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continue
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key_columns = self.introspection.get_key_columns(cursor, table_name)
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for column_name, referenced_table_name, referenced_column_name in key_columns:
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cursor.execute("""
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SELECT REFERRING.`%s`, REFERRING.`%s` FROM `%s` as REFERRING
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LEFT JOIN `%s` as REFERRED
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ON (REFERRING.`%s` = REFERRED.`%s`)
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WHERE REFERRING.`%s` IS NOT NULL AND REFERRED.`%s` IS NULL"""
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% (primary_key_column_name, column_name, table_name, referenced_table_name,
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column_name, referenced_column_name, column_name, referenced_column_name))
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for bad_row in cursor.fetchall():
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raise utils.IntegrityError("The row in table '%s' with primary key '%s' has an invalid "
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"foreign key: %s.%s contains a value '%s' that does not have a corresponding value in %s.%s."
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% (table_name, bad_row[0], table_name, column_name, bad_row[1],
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referenced_table_name, referenced_column_name))
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def close(self):
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self.validate_thread_sharing()
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# If database is in memory, closing the connection destroys the
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# database. To prevent accidental data loss, ignore close requests on
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# an in-memory db.
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if self.settings_dict['NAME'] != ":memory:":
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BaseDatabaseWrapper.close(self)
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FORMAT_QMARK_REGEX = re.compile(r'(?<!%)%s')
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class SQLiteCursorWrapper(Database.Cursor):
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"""
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Django uses "format" style placeholders, but pysqlite2 uses "qmark" style.
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This fixes it -- but note that if you want to use a literal "%s" in a query,
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you'll need to use "%%s".
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"""
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def execute(self, query, params=()):
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query = self.convert_query(query)
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try:
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return Database.Cursor.execute(self, query, params)
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except Database.IntegrityError, e:
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raise utils.IntegrityError, utils.IntegrityError(*tuple(e)), sys.exc_info()[2]
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except Database.DatabaseError, e:
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raise utils.DatabaseError, utils.DatabaseError(*tuple(e)), sys.exc_info()[2]
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def executemany(self, query, param_list):
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query = self.convert_query(query)
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try:
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return Database.Cursor.executemany(self, query, param_list)
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except Database.IntegrityError, e:
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raise utils.IntegrityError, utils.IntegrityError(*tuple(e)), sys.exc_info()[2]
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except Database.DatabaseError, e:
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raise utils.DatabaseError, utils.DatabaseError(*tuple(e)), sys.exc_info()[2]
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def convert_query(self, query):
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return FORMAT_QMARK_REGEX.sub('?', query).replace('%%','%')
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def _sqlite_extract(lookup_type, dt):
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if dt is None:
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return None
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try:
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dt = util.typecast_timestamp(dt)
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except (ValueError, TypeError):
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return None
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if lookup_type == 'week_day':
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return (dt.isoweekday() % 7) + 1
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else:
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return getattr(dt, lookup_type)
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def _sqlite_date_trunc(lookup_type, dt):
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try:
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dt = util.typecast_timestamp(dt)
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except (ValueError, TypeError):
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return None
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if lookup_type == 'year':
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return "%i-01-01 00:00:00" % dt.year
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elif lookup_type == 'month':
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return "%i-%02i-01 00:00:00" % (dt.year, dt.month)
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elif lookup_type == 'day':
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return "%i-%02i-%02i 00:00:00" % (dt.year, dt.month, dt.day)
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def _sqlite_format_dtdelta(dt, conn, days, secs, usecs):
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try:
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dt = util.typecast_timestamp(dt)
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delta = datetime.timedelta(int(days), int(secs), int(usecs))
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if conn.strip() == '+':
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dt = dt + delta
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else:
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dt = dt - delta
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except (ValueError, TypeError):
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return None
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# typecast_timestamp returns a date or a datetime without timezone.
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# It will be formatted as "%Y-%m-%d" or "%Y-%m-%d %H:%M:%S[.%f]"
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return str(dt)
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def _sqlite_regexp(re_pattern, re_string):
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try:
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return bool(re.search(re_pattern, re_string))
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except:
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return False
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