Initial commit. Basic models mostly done.

venv/lib/python3.8/site-packages/django/db/backends/mysql/features.py

@@ -0,0 +1,138 @@
+import operator
+
+from django.db.backends.base.features import BaseDatabaseFeatures
+from django.utils.functional import cached_property
+
+
+class DatabaseFeatures(BaseDatabaseFeatures):
+    empty_fetchmany_value = ()
+    update_can_self_select = False
+    allows_group_by_pk = True
+    related_fields_match_type = True
+    # MySQL doesn't support sliced subqueries with IN/ALL/ANY/SOME.
+    allow_sliced_subqueries_with_in = False
+    has_select_for_update = True
+    supports_forward_references = False
+    supports_regex_backreferencing = False
+    supports_date_lookup_using_string = False
+    can_introspect_autofield = True
+    can_introspect_binary_field = False
+    can_introspect_duration_field = False
+    can_introspect_small_integer_field = True
+    can_introspect_positive_integer_field = True
+    introspected_boolean_field_type = 'IntegerField'
+    supports_index_column_ordering = False
+    supports_timezones = False
+    requires_explicit_null_ordering_when_grouping = True
+    allows_auto_pk_0 = False
+    can_release_savepoints = True
+    atomic_transactions = False
+    can_clone_databases = True
+    supports_temporal_subtraction = True
+    supports_select_intersection = False
+    supports_select_difference = False
+    supports_slicing_ordering_in_compound = True
+    supports_index_on_text_field = False
+    has_case_insensitive_like = False
+    create_test_procedure_without_params_sql = """
+        CREATE PROCEDURE test_procedure ()
+        BEGIN
+            DECLARE V_I INTEGER;
+            SET V_I = 1;
+        END;
+    """
+    create_test_procedure_with_int_param_sql = """
+        CREATE PROCEDURE test_procedure (P_I INTEGER)
+        BEGIN
+            DECLARE V_I INTEGER;
+            SET V_I = P_I;
+        END;
+    """
+    db_functions_convert_bytes_to_str = True
+    # Alias MySQL's TRADITIONAL to TEXT for consistency with other backends.
+    supported_explain_formats = {'JSON', 'TEXT', 'TRADITIONAL'}
+    # Neither MySQL nor MariaDB support partial indexes.
+    supports_partial_indexes = False
+
+    @cached_property
+    def _mysql_storage_engine(self):
+        "Internal method used in Django tests. Don't rely on this from your code"
+        with self.connection.cursor() as cursor:
+            cursor.execute("SELECT ENGINE FROM INFORMATION_SCHEMA.ENGINES WHERE SUPPORT = 'DEFAULT'")
+            result = cursor.fetchone()
+        return result[0]
+
+    @cached_property
+    def can_introspect_foreign_keys(self):
+        "Confirm support for introspected foreign keys"
+        return self._mysql_storage_engine != 'MyISAM'
+
+    @cached_property
+    def has_zoneinfo_database(self):
+        # Test if the time zone definitions are installed. CONVERT_TZ returns
+        # NULL if 'UTC' timezone isn't loaded into the mysql.time_zone.
+        with self.connection.cursor() as cursor:
+            cursor.execute("SELECT CONVERT_TZ('2001-01-01 01:00:00', 'UTC', 'UTC')")
+            return cursor.fetchone()[0] is not None
+
+    @cached_property
+    def is_sql_auto_is_null_enabled(self):
+        with self.connection.cursor() as cursor:
+            cursor.execute('SELECT @@SQL_AUTO_IS_NULL')
+            result = cursor.fetchone()
+            return result and result[0] == 1
+
+    @cached_property
+    def supports_over_clause(self):
+        if self.connection.mysql_is_mariadb:
+            return self.connection.mysql_version >= (10, 2)
+        return self.connection.mysql_version >= (8, 0, 2)
+
+    @cached_property
+    def supports_column_check_constraints(self):
+        if self.connection.mysql_is_mariadb:
+            return self.connection.mysql_version >= (10, 2, 1)
+        return self.connection.mysql_version >= (8, 0, 16)
+
+    supports_table_check_constraints = property(operator.attrgetter('supports_column_check_constraints'))
+
+    @cached_property
+    def can_introspect_check_constraints(self):
+        if self.connection.mysql_is_mariadb:
+            version = self.connection.mysql_version
+            return (version >= (10, 2, 22) and version < (10, 3)) or version >= (10, 3, 10)
+        return self.connection.mysql_version >= (8, 0, 16)
+
+    @cached_property
+    def has_select_for_update_skip_locked(self):
+        return not self.connection.mysql_is_mariadb and self.connection.mysql_version >= (8, 0, 1)
+
+    @cached_property
+    def has_select_for_update_nowait(self):
+        if self.connection.mysql_is_mariadb:
+            return self.connection.mysql_version >= (10, 3, 0)
+        return self.connection.mysql_version >= (8, 0, 1)
+
+    @cached_property
+    def needs_explain_extended(self):
+        # EXTENDED is deprecated (and not required) in MySQL 5.7.
+        return not self.connection.mysql_is_mariadb and self.connection.mysql_version < (5, 7)
+
+    @cached_property
+    def supports_transactions(self):
+        """
+        All storage engines except MyISAM support transactions.
+        """
+        return self._mysql_storage_engine != 'MyISAM'
+
+    @cached_property
+    def ignores_table_name_case(self):
+        with self.connection.cursor() as cursor:
+            cursor.execute('SELECT @@LOWER_CASE_TABLE_NAMES')
+            result = cursor.fetchone()
+            return result and result[0] != 0
+
+    @cached_property
+    def supports_default_in_lead_lag(self):
+        # To be added in https://jira.mariadb.org/browse/MDEV-12981.
+        return not self.connection.mysql_is_mariadb