425 lines
17 KiB
Python
425 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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from __future__ import unicode_literals
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import datetime
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import decimal
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import re
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import warnings
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from django.conf import settings
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from django.db import utils
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from django.db.backends import utils as backend_utils
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from django.db.backends.base.base import BaseDatabaseWrapper
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from django.db.backends.base.validation import BaseDatabaseValidation
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from django.utils import six, timezone
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from django.utils.dateparse import parse_date, parse_duration, parse_time
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from django.utils.encoding import force_text
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from django.utils.safestring import SafeBytes
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try:
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import pytz
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except ImportError:
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pytz = None
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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:
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from sqlite3 import dbapi2 as Database
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except ImportError as 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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# Some of these import sqlite3, so import them after checking if it's installed.
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from .client import DatabaseClient
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from .creation import DatabaseCreation
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from .features import DatabaseFeatures
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from .introspection import DatabaseIntrospection
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from .operations import DatabaseOperations
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from .schema import DatabaseSchemaEditor
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from .utils import parse_datetime_with_timezone_support
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DatabaseError = Database.DatabaseError
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IntegrityError = Database.IntegrityError
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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("SQLite received a naive datetime (%s)"
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" 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(str(" "))
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def decoder(conv_func):
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""" The Python sqlite3 interface returns always byte strings.
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This function converts the received value to a regular string before
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passing it to the receiver function.
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"""
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return lambda s: conv_func(s.decode('utf-8'))
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Database.register_converter(str("bool"), decoder(lambda s: s == '1'))
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Database.register_converter(str("time"), decoder(parse_time))
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Database.register_converter(str("date"), decoder(parse_date))
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Database.register_converter(str("datetime"), decoder(parse_datetime_with_timezone_support))
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Database.register_converter(str("timestamp"), decoder(parse_datetime_with_timezone_support))
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Database.register_converter(str("TIMESTAMP"), decoder(parse_datetime_with_timezone_support))
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Database.register_converter(str("decimal"), decoder(backend_utils.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, backend_utils.rev_typecast_decimal)
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if six.PY2:
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Database.register_adapter(str, lambda s: s.decode('utf-8'))
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Database.register_adapter(SafeBytes, lambda s: s.decode('utf-8'))
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class DatabaseWrapper(BaseDatabaseWrapper):
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vendor = 'sqlite'
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# SQLite doesn't actually support most of these types, but it "does the right
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# thing" given more verbose field definitions, so leave them as is so that
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# schema inspection is more useful.
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data_types = {
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'AutoField': 'integer',
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'BinaryField': 'BLOB',
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'BooleanField': 'bool',
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'CharField': 'varchar(%(max_length)s)',
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'CommaSeparatedIntegerField': 'varchar(%(max_length)s)',
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'DateField': 'date',
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'DateTimeField': 'datetime',
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'DecimalField': 'decimal',
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'DurationField': 'bigint',
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'FileField': 'varchar(%(max_length)s)',
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'FilePathField': 'varchar(%(max_length)s)',
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'FloatField': 'real',
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'IntegerField': 'integer',
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'BigIntegerField': 'bigint',
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'IPAddressField': 'char(15)',
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'GenericIPAddressField': 'char(39)',
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'NullBooleanField': 'bool',
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'OneToOneField': 'integer',
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'PositiveIntegerField': 'integer unsigned',
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'PositiveSmallIntegerField': 'smallint unsigned',
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'SlugField': 'varchar(%(max_length)s)',
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'SmallIntegerField': 'smallint',
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'TextField': 'text',
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'TimeField': 'time',
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'UUIDField': 'char(32)',
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}
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data_types_suffix = {
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'AutoField': 'AUTOINCREMENT',
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}
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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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# The patterns below are used to generate SQL pattern lookup clauses when
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# the right-hand side of the lookup isn't a raw string (it might be an expression
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# or the result of a bilateral transformation).
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# In those cases, special characters for LIKE operators (e.g. \, *, _) should be
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# escaped on database side.
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#
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# Note: we use str.format() here for readability as '%' is used as a wildcard for
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# the LIKE operator.
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pattern_esc = r"REPLACE(REPLACE(REPLACE({}, '\', '\\'), '%%', '\%%'), '_', '\_')"
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pattern_ops = {
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'contains': r"LIKE '%%' || {} || '%%' ESCAPE '\'",
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'icontains': r"LIKE '%%' || UPPER({}) || '%%' ESCAPE '\'",
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'startswith': r"LIKE {} || '%%' ESCAPE '\'",
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'istartswith': r"LIKE UPPER({}) || '%%' ESCAPE '\'",
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'endswith': r"LIKE '%%' || {} ESCAPE '\'",
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'iendswith': r"LIKE '%%' || UPPER({}) ESCAPE '\'",
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}
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Database = Database
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SchemaEditorClass = DatabaseSchemaEditor
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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 get_connection_params(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(
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"settings.DATABASES is improperly configured. "
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"Please supply the NAME value.")
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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 overridden 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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if self.features.can_share_in_memory_db:
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kwargs.update({'uri': True})
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return kwargs
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def get_new_connection(self, conn_params):
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conn = Database.connect(**conn_params)
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conn.create_function("django_date_extract", 2, _sqlite_date_extract)
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conn.create_function("django_date_trunc", 2, _sqlite_date_trunc)
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conn.create_function("django_datetime_extract", 3, _sqlite_datetime_extract)
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conn.create_function("django_datetime_trunc", 3, _sqlite_datetime_trunc)
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conn.create_function("regexp", 2, _sqlite_regexp)
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conn.create_function("django_format_dtdelta", 3, _sqlite_format_dtdelta)
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conn.create_function("django_power", 2, _sqlite_power)
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return conn
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def init_connection_state(self):
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pass
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def create_cursor(self):
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return self.connection.cursor(factory=SQLiteCursorWrapper)
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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 not self.is_in_memory_db(self.settings_dict['NAME']):
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BaseDatabaseWrapper.close(self)
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def _savepoint_allowed(self):
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# Two conditions are required here:
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# - A sufficiently recent version of SQLite to support savepoints,
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# - Being in a transaction, which can only happen inside 'atomic'.
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# When 'isolation_level' is not None, sqlite3 commits before each
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# savepoint; it's a bug. When it is None, savepoints don't make sense
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# because autocommit is enabled. The only exception is inside 'atomic'
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# blocks. To work around that bug, on SQLite, 'atomic' starts a
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# transaction explicitly rather than simply disable autocommit.
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return self.features.uses_savepoints and self.in_atomic_block
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def _set_autocommit(self, autocommit):
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if autocommit:
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level = None
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else:
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# sqlite3's internal default is ''. It's different from None.
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# See Modules/_sqlite/connection.c.
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level = ''
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# 'isolation_level' is a misleading API.
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# SQLite always runs at the SERIALIZABLE isolation level.
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with self.wrap_database_errors:
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self.connection.isolation_level = level
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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
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key references. This method is intended to be used in conjunction with
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`disable_constraint_checking()` and `enable_constraint_checking()`, to
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determine if rows with invalid references were entered while constraint
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checks were off.
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Raises an IntegrityError on the first invalid foreign key reference
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encountered (if any) and provides detailed information about the
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invalid reference in the error message.
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Backends can override this method if they can more directly apply
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constraint checking (e.g. via "SET CONSTRAINTS 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.table_names(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 is_usable(self):
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return True
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def _start_transaction_under_autocommit(self):
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"""
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Start a transaction explicitly in autocommit mode.
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Staying in autocommit mode works around a bug of sqlite3 that breaks
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savepoints when autocommit is disabled.
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"""
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self.cursor().execute("BEGIN")
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def is_in_memory_db(self, name):
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return name == ":memory:" or "mode=memory" in name
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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=None):
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if params is None:
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return Database.Cursor.execute(self, query)
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query = self.convert_query(query)
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return Database.Cursor.execute(self, query, params)
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def executemany(self, query, param_list):
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query = self.convert_query(query)
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return Database.Cursor.executemany(self, query, param_list)
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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_date_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 = backend_utils.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 = backend_utils.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" % dt.year
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elif lookup_type == 'month':
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return "%i-%02i-01" % (dt.year, dt.month)
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elif lookup_type == 'day':
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return "%i-%02i-%02i" % (dt.year, dt.month, dt.day)
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def _sqlite_datetime_extract(lookup_type, dt, tzname):
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if dt is None:
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return None
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try:
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dt = backend_utils.typecast_timestamp(dt)
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except (ValueError, TypeError):
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return None
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if tzname is not None:
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dt = timezone.localtime(dt, pytz.timezone(tzname))
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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_datetime_trunc(lookup_type, dt, tzname):
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try:
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dt = backend_utils.typecast_timestamp(dt)
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except (ValueError, TypeError):
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return None
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if tzname is not None:
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dt = timezone.localtime(dt, pytz.timezone(tzname))
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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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elif lookup_type == 'hour':
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return "%i-%02i-%02i %02i:00:00" % (dt.year, dt.month, dt.day, dt.hour)
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elif lookup_type == 'minute':
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return "%i-%02i-%02i %02i:%02i:00" % (dt.year, dt.month, dt.day, dt.hour, dt.minute)
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elif lookup_type == 'second':
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return "%i-%02i-%02i %02i:%02i:%02i" % (dt.year, dt.month, dt.day, dt.hour, dt.minute, dt.second)
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def _sqlite_format_dtdelta(conn, lhs, rhs):
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"""
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LHS and RHS can be either:
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- An integer number of microseconds
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- A string representing a timedelta object
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- A string representing a datetime
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"""
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try:
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if isinstance(lhs, six.integer_types):
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lhs = str(decimal.Decimal(lhs) / decimal.Decimal(1000000))
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real_lhs = parse_duration(lhs)
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if real_lhs is None:
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real_lhs = backend_utils.typecast_timestamp(lhs)
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if isinstance(rhs, six.integer_types):
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rhs = str(decimal.Decimal(rhs) / decimal.Decimal(1000000))
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real_rhs = parse_duration(rhs)
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if real_rhs is None:
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real_rhs = backend_utils.typecast_timestamp(rhs)
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if conn.strip() == '+':
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out = real_lhs + real_rhs
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else:
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out = real_lhs - real_rhs
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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(out)
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def _sqlite_regexp(re_pattern, re_string):
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return bool(re.search(re_pattern, force_text(re_string))) if re_string is not None else False
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def _sqlite_power(x, y):
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return x ** y
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