dBASE　IV中三种连接操作有效性的比较

Comparison of Effectiveness of Three Join Operations in dBASE IV

本文就ｄＢＡＳＥＩＶ中三种连接操作（ＪＯＩＮ、ＳＥＴＲＥＬＡＴＩＯＮ／ＳＥＴＳｋＩＰ及ＳＱＬＳＥＬＥＣＴ）在实现连接各个库时的有效性方面进行了对比，结论是ＳＱＬＳＥＬＥＣＴ操作在连接各个库时的有效性最好。

This paper examines effectiveness of three ways to implement the join operation indBASE IV, the three ways are JOIN ,SET RELARION/SET SKIP and SOL SELBCT. It is concluded that SQL SELECT command is the best way to join tables in the three ways.