ops.py 文件源码

def drop_constraint(
            cls, operations, constraint_name, table_name,
            type_=None, schema=None):
        """Drop a constraint of the given name, typically via DROP CONSTRAINT.

        :param constraint_name: name of the constraint.
        :param table_name: table name.
        :param type_: optional, required on MySQL.  can be
         'foreignkey', 'primary', 'unique', or 'check'.
        :param schema: Optional schema name to operate within.  To control
         quoting of the schema outside of the default behavior, use
         the SQLAlchemy construct
         :class:`~sqlalchemy.sql.elements.quoted_name`.

         .. versionadded:: 0.7.0 'schema' can now accept a
            :class:`~sqlalchemy.sql.elements.quoted_name` construct.

        .. versionchanged:: 0.8.0 The following positional argument names
           have been changed:

           * name -> constraint_name

        """

        op = cls(constraint_name, table_name, type_=type_, schema=schema)
        return operations.invoke(op)