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JIRA数据库设计的一点学习总结

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Jun 07, 2016 pm 03:23 PM

jirastudySummarizedatabasedesign

今天无聊，把JIRA的数据库导过来(MySQL版的)，在Navicat里查看了一下。总结出以下几点：一、各种类型： Tables: N个 Views:0个 Functions:0个 Trigger:0个二、外键使用：表设计中外键使用得很少，除了一组貌自动生成的表外，其它基本没有外键外键的使用

今天无聊，把JIRA的数据库导过来(MySQL版的)，在Navicat里查看了一下。总结出以下几点：

一、各种类型：

Tables: N个

Views:0个

Functions:0个

Trigger:0个

二、外键使用：

表设计中外键使用得很少，除了一组貌似自动生成的表外，其它基本没有外键

外键的使用，网上有不少争论：

http://www.itpub.net/thread-1313696-1-1.html

http://www.itpub.net/thread-1312844-1-1.html

三、表数据类型选型：

基本只使用了以下几种

decimal:18

decimal:9

varchar(255)

char(x)根据需要

longtext

datetime

四、表名，字段命名规范

以英文全称为主，如AUTHOR

多个单词有用下划线，也没有没有的，如：PROJECTLEVEL，PASSWORD_HASH，感觉这一块做得不是很规范

每个表都包含主键，大都数以ID为主键，也用不少多主键的表

总结：

因为要兼容多个数据库，所以选择尽量少的数据类型，提高在各种数据库里的兼容性，引入尽量少的数据库特性

外键的问题，不发表意见，见那两个链接

id，一般都用decimal(18)，为大数据量提供了保障（mysql里支持bigint的，但Oracle之类的没有，为了通用性），为什么是18？对应到java.lang.Long就知道了。

decimal(18)，可以映射为Long(JIRA是用Java编写的)，如果是19位的话，可能会超过Long的最大数9223372036854775807

varchar一般用varchar(255)多，用数据库了，多点损耗比长度不够要好

以下是预览图：

JIRA数据库设计的一点学习总结

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