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Mysql索引
阅读量:93 次
发布时间:2019-02-25

本文共 1505 字,大约阅读时间需要 5 分钟。

MySQL?????????????

??????????????????????????????????????????????????????????????????????????????MySQL???


????????

???MySQL??????????????????????????????????????????????????????????????????????????????????MySQL??????????????????????????


???????

??????????????IO??????????????????????????????????????????????????B+??????????????????????????IO???

B+??????

B+????????????????????????????????????

  • ???????????????????????????IO???
  • ?????????????????????????????
  • ?????????????????????
  • ???????????????????????IO???????????????????????


    B+????

  • ?????????????

    ????????????????????int??????????????????????

  • ??????????

    B+???????????????????????????????????????????

  • ??????

    ????????????????????????????


  • ??????????

    1. ????

    • ?????????????????
    • ????????????????????
    • ?????????????????????
    • ??????????????????????????

    2. ??????

    • ???????ID??????????????????
    • ?????????????????????????
    • ???????????????????????

    ?????????

    1. ????

    • ??????????

      create table s1(  id int,  name varchar(20),  gender char(6),  email varchar(50),  primary key(id));
      create index idx_name on s1(name);
    • ???????

      create index idx_id on s1(id);
    • ?????

      drop index idx_name on s1;

    2. ??????

    • ?????????????????????????
    • ??????????????????????
    • ??????????????????

    ?????????

    ???????????????????

    • ??????email LIKE '%cn%'?
    • ??????reverse(email) = 'wupeiqi'?
    • ???????????nid != 123??nid???????????

    ???????

  • ????????????????????
  • ????*????????????
  • ?????????????????????

  • ??

    ????????????????????????????????????????IO???????????????????????????????????????????????????????????????????

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