This way the database engine will stop scanning for records after it finds just 1, instead of going thru the whole table or index.

数据库引擎在找到一条记录后就停止继续扫描，而不是扫完整张表或者索引。

youdao

This way the database engine will stop scanning for records after it finds just 1, instead of going thru the whole table or index.

数据库引擎在找到一条记录后就停止继续扫描，而不是扫完整张表或者索引。

youdao