本文共 958 字,大约阅读时间需要 3 分钟。
方式一:
SELECT id,bookName,price,shelve,authorId FROM book WHERE authorId=#id# SELECT id, authorName, description FROM author WHERE isDelete = 0 AND authorName LIKE '%$authorName$%' ORDER BY id LIMIT #start#, #end#
方式二:
SELECT id,bookName,price,shelve,authorId FROM book WHERE authorId=#id# SELECT a.id, a.authorName, a.description,b.id as bookId,b.bookName,b.price,b.shelve FROM author a join book b on a.id=b.authorId WHERE a.isDelete = 0 AND a.authorName LIKE '%$authorName$%' ORDER BY a.id LIMIT #start#, #end#
方式一:结构清晰,但查询会有N+1的问题(主表查询一次,子表查询N次)。
方式二:是方式一的改进,一次查询出所有结果,性能更好,但结构复杂时不易维护。在子表信息查询次数较少时,通过使用ibatis的延迟加载机制方式一会比较高效。
转载地址:http://iykkb.baihongyu.com/