Based on standard SQL ( Stuctured Query Language), we develop the schema definition language for an active real time database system, propose the process of implementation for the schema definition language in detail, define logical structure of data dictionary as well as. 在标准SQL语言的基础上,开发了主动实时数据库系统的模式定义语言(ESDL),详细描述了模式定义语言处理的过程,定义了数据字典的逻辑结构。