ops.py 文件源码

def create_primary_key(
            cls, operations,
            constraint_name, table_name, columns, schema=None):
        """Issue a "create primary key" instruction using the current
        migration context.

        e.g.::

            from alembic import op
            op.create_primary_key(
                        "pk_my_table", "my_table",
                        ["id", "version"]
                    )

        This internally generates a :class:`~sqlalchemy.schema.Table` object
        containing the necessary columns, then generates a new
        :class:`~sqlalchemy.schema.PrimaryKeyConstraint`
        object which it then associates with the
        :class:`~sqlalchemy.schema.Table`.
        Any event listeners associated with this action will be fired
        off normally.   The :class:`~sqlalchemy.schema.AddConstraint`
        construct is ultimately used to generate the ALTER statement.

        :param name: Name of the primary key constraint.  The name is necessary
         so that an ALTER statement can be emitted.  For setups that
         use an automated naming scheme such as that described at
         :ref:`sqla:constraint_naming_conventions`
         ``name`` here can be ``None``, as the event listener will
         apply the name to the constraint object when it is associated
         with the table.
        :param table_name: String name of the target table.
        :param columns: a list of string column names to be applied to the
         primary key constraint.
        :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
           * cols -> columns

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