简体中文(ZH-CN) English(EN) 繁体中文(ZH-TW) 日本語(JA) 한국어(KO) Melayu(MS) Français(FR) Deutsch(DE)
Home > Database > Mysql Tutorial > body text

关于Oracle调优中“建立索引”的补充

WBOY
Release： 2016-06-07 17:07:38
Original
896 people have browsed it

关于Oracle调优中ldquo;建立索引rdquo;的补充

建立索引是很好地调优方法，可以大幅提高查询速度。

但是除了在每个字段上建立索引之外，还可以有如下的建立方法：

1. 建立查询条件的联合索引：

把查询条件中 某个表用到的全部字段 合在一起，建立一个索引，，可以提高查询效率

2. 建立查询结果的联合索引

把查询结果中 某个表被查出来的全部字段 合在一起，建立一个索引，可以提高查询效率

3.  建立基于多个字段上的unique索引

unique索引不一定仅仅由主键决定，如果多个字段联合起来能唯一确定一条数据，那么可以把它们联合起来建立一条索引

linux

Related labels：
oracle database
source：php.cn
Previous article：数据库设计文档DBMS的快速转换 Next article：Oracle 字符集的查看和修改
Statement of this Website
The content of this article is voluntarily contributed by netizens, and the copyright belongs to the original author. This site does not assume corresponding legal responsibility. If you find any content suspected of plagiarism or infringement, please contact admin@php.cn
Latest Articles by Author
Latest Issues
Regular expression to match words I have a script where I am trying to match new job names with existing job names in a data...
From 2024-04-06 21:24:04
0
1
606
Calculate the sum of fields in another table using MySQL SQL query I have a schema like this: User table with attributes "user_id" and "userna...
From 2024-04-06 19:39:29
0
1
441
MySQL: "Select text from... as <variable here or subquery>" I have the following table with the following data: id text language 1 german text german ...
From 2024-04-06 19:25:54
0
2
529
MySQL gets data from multiple tables I have a eg_design table which contains the following columns: and eg_domains table which ...
From 2024-04-06 18:42:44
0
2
479
Group MySQL results by ID for looping over I have a table with flight data in mysql. I'm writing a php code that will group and displ...
From 2024-04-06 17:27:56
0
1
406
Related Topics
More>
Popular Recommendations
Popular Tutorials
More>
Related Tutorials
Popular Recommendations
Latest courses
Latest Downloads
More>
Web Effects
Website Source Code
Website Materials
Front End Template
About us Disclaimer Sitemap
php.cn：Public welfare online PHP training，Help PHP learners grow quickly！