88 lines
3.1 KiB
Python
88 lines
3.1 KiB
Python
from django.db.backends.base.features import BaseDatabaseFeatures
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from django.utils.functional import cached_property
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from .base import Database
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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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class DatabaseFeatures(BaseDatabaseFeatures):
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empty_fetchmany_value = ()
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update_can_self_select = False
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allows_group_by_pk = True
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related_fields_match_type = True
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allow_sliced_subqueries = False
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has_bulk_insert = True
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has_select_for_update = True
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has_select_for_update_nowait = False
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supports_forward_references = False
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supports_regex_backreferencing = False
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supports_date_lookup_using_string = False
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can_introspect_autofield = True
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can_introspect_binary_field = False
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can_introspect_small_integer_field = True
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supports_index_column_ordering = False
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supports_timezones = False
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requires_explicit_null_ordering_when_grouping = True
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allows_auto_pk_0 = False
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uses_savepoints = True
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can_release_savepoints = True
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atomic_transactions = False
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supports_column_check_constraints = False
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can_clone_databases = True
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supports_temporal_subtraction = True
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@cached_property
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def _mysql_storage_engine(self):
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"Internal method used in Django tests. Don't rely on this from your code"
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with self.connection.cursor() as cursor:
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cursor.execute("SELECT ENGINE FROM INFORMATION_SCHEMA.ENGINES WHERE SUPPORT = 'DEFAULT'")
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result = cursor.fetchone()
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return result[0]
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@cached_property
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def can_introspect_foreign_keys(self):
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"Confirm support for introspected foreign keys"
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return self._mysql_storage_engine != 'MyISAM'
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@cached_property
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def supports_microsecond_precision(self):
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# See https://github.com/farcepest/MySQLdb1/issues/24 for the reason
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# about requiring MySQLdb 1.2.5
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return self.connection.mysql_version >= (5, 6, 4) and Database.version_info >= (1, 2, 5)
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@cached_property
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def has_zoneinfo_database(self):
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# MySQL accepts full time zones names (eg. Africa/Nairobi) but rejects
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# abbreviations (eg. EAT). When pytz isn't installed and the current
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# time zone is LocalTimezone (the only sensible value in this
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# context), the current time zone name will be an abbreviation. As a
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# consequence, MySQL cannot perform time zone conversions reliably.
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if pytz is None:
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return False
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# Test if the time zone definitions are installed.
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with self.connection.cursor() as cursor:
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cursor.execute("SELECT 1 FROM mysql.time_zone LIMIT 1")
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return cursor.fetchone() is not None
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def introspected_boolean_field_type(self, *args, **kwargs):
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return 'IntegerField'
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@cached_property
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def is_sql_auto_is_null_enabled(self):
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with self.connection.cursor() as cursor:
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cursor.execute('SELECT @@SQL_AUTO_IS_NULL')
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result = cursor.fetchone()
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return result and result[0] == 1
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@cached_property
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def supports_transactions(self):
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"""
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All storage engines except MyISAM support transactions.
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"""
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return self._mysql_storage_engine != 'MyISAM'
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