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Lib/site-packages/django/db/backends/sqlite3/features.py

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