Method as_sql

django/db/models/sql/compiler.py:1800–1922

(self)

        return placeholder_rows, param_rows

    def as_sql(self):
        qn = self.quote_name
        opts = self.query.get_meta()
        insert_statement = self.connection.ops.insert_statement(
            on_conflict=self.query.on_conflict,
        )
        result = ["%s %s" % (insert_statement, qn(opts.db_table))]

        if fields := list(self.query.fields):
            from django.db.models.expressions import DatabaseDefault

            supports_default_keyword_in_bulk_insert = (
                self.connection.features.supports_default_keyword_in_bulk_insert
            )
            value_cols = []
            for field in list(fields):
                field_prepare = partial(self.prepare_value, field)
                field_pre_save = partial(self.pre_save_val, field)

                field_values = []
                for obj in self.query.objs:
                    value = field_pre_save(obj)
                    if not isinstance(value, DatabaseDefault):
                        value = field_prepare(value)
                    field_values.append(value)

                if not field.has_db_default():
                    value_cols.append(field_values)
                    continue

                # If all values are DEFAULT don't include the field and its
                # values in the query as they are redundant and could prevent
                # optimizations. This cannot be done if we're dealing with the
                # last field as INSERT statements require at least one.
                if len(fields) > 1 and all(
                    isinstance(value, DatabaseDefault) for value in field_values
                ):
                    fields.remove(field)
                    continue

                if supports_default_keyword_in_bulk_insert:
                    value_cols.append(field_values)
                    continue

                # If the field cannot be excluded from the INSERT for the
                # reasons listed above and the backend doesn't support the
                # DEFAULT keyword each values must be expanded into their
                # underlying expressions.
                prepared_db_default = field_prepare(field.db_default)
                field_values = [
                    (
                        prepared_db_default
                        if isinstance(value, DatabaseDefault)
                        else value
                    )
                    for value in field_values
                ]
                value_cols.append(field_values)