loaddata.py 文件源码

def loaddata(self, fixture_labels):
        connection = connections[self.using]

        # Keep a count of the installed objects and fixtures
        self.fixture_count = 0
        self.loaded_object_count = 0
        self.fixture_object_count = 0
        self.models = set()

        self.serialization_formats = serializers.get_public_serializer_formats()
        # Forcing binary mode may be revisited after dropping Python 2 support (see #22399)
        self.compression_formats = {
            None: (open, 'rb'),
            'gz': (gzip.GzipFile, 'rb'),
            'zip': (SingleZipReader, 'r'),
        }
        if has_bz2:
            self.compression_formats['bz2'] = (bz2.BZ2File, 'r')

        with connection.constraint_checks_disabled():
            for fixture_label in fixture_labels:
                self.load_label(fixture_label)

        # Since we disabled constraint checks, we must manually check for
        # any invalid keys that might have been added
        table_names = [model._meta.db_table for model in self.models]
        try:
            connection.check_constraints(table_names=table_names)
        except Exception as e:
            e.args = ("Problem installing fixtures: %s" % e,)
            raise

        # If we found even one object in a fixture, we need to reset the
        # database sequences.
        if self.loaded_object_count > 0:
            sequence_sql = connection.ops.sequence_reset_sql(no_style(), self.models)
            if sequence_sql:
                if self.verbosity >= 2:
                    self.stdout.write("Resetting sequences\n")
                with connection.cursor() as cursor:
                    for line in sequence_sql:
                        cursor.execute(line)

        if self.verbosity >= 1:
            if self.fixture_count == 0 and self.hide_empty:
                pass
            elif self.fixture_object_count == self.loaded_object_count:
                self.stdout.write("Installed %d object(s) from %d fixture(s)" %
                    (self.loaded_object_count, self.fixture_count))
            else:
                self.stdout.write("Installed %d object(s) (of %d) from %d fixture(s)" %
                    (self.loaded_object_count, self.fixture_object_count, self.fixture_count))