拥有检测数据库是否连接成功的功能,以及第一个记录,前一个记录,下一个记录,以及最后一个的记录的检测以及显示功能.适合初学者.-Whether or not have a database connection Detect function, as well as the first record, previous record, next record, as well as the last record of the detection and display. Suitable for