67 lines
2.7 KiB
Python
67 lines
2.7 KiB
Python
import operator
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from django.db import transaction
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from django.db.backends.base.features import BaseDatabaseFeatures
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from django.db.utils import OperationalError
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from django.utils.functional import cached_property
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from .base import Database
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class DatabaseFeatures(BaseDatabaseFeatures):
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# SQLite can read from a cursor since SQLite 3.6.5, subject to the caveat
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# that statements within a connection aren't isolated from each other. See
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# https://sqlite.org/isolation.html.
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can_use_chunked_reads = True
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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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max_query_params = 999
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supports_mixed_date_datetime_comparisons = False
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supports_transactions = True
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atomic_transactions = False
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can_rollback_ddl = True
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supports_atomic_references_rename = Database.sqlite_version_info >= (3, 26, 0)
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can_create_inline_fk = False
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supports_paramstyle_pyformat = False
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can_clone_databases = True
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supports_temporal_subtraction = True
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ignores_table_name_case = True
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supports_cast_with_precision = False
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time_cast_precision = 3
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can_release_savepoints = True
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# Is "ALTER TABLE ... RENAME COLUMN" supported?
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can_alter_table_rename_column = Database.sqlite_version_info >= (3, 25, 0)
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supports_parentheses_in_compound = False
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# Deferred constraint checks can be emulated on SQLite < 3.20 but not in a
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# reasonably performant way.
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supports_pragma_foreign_key_check = Database.sqlite_version_info >= (3, 20, 0)
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can_defer_constraint_checks = supports_pragma_foreign_key_check
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supports_functions_in_partial_indexes = Database.sqlite_version_info >= (3, 15, 0)
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supports_over_clause = Database.sqlite_version_info >= (3, 25, 0)
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supports_frame_range_fixed_distance = Database.sqlite_version_info >= (3, 28, 0)
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supports_aggregate_filter_clause = Database.sqlite_version_info >= (3, 30, 1)
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supports_order_by_nulls_modifier = Database.sqlite_version_info >= (3, 30, 0)
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order_by_nulls_first = True
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@cached_property
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def introspected_field_types(self):
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return{
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**super().introspected_field_types,
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'BigAutoField': 'AutoField',
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'DurationField': 'BigIntegerField',
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'GenericIPAddressField': 'CharField',
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'SmallAutoField': 'AutoField',
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}
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@cached_property
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def supports_json_field(self):
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try:
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with self.connection.cursor() as cursor, transaction.atomic():
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cursor.execute('SELECT JSON(\'{"a": "b"}\')')
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except OperationalError:
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return False
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return True
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can_introspect_json_field = property(operator.attrgetter('supports_json_field'))
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