postgresql liquibase 的枚举数据类型
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enum data type for liquibase
提问by Ali Taha Ali Mahboub
I'm currently working on a liquibase.xml file to create table table_a. One of my fields is <column name="state" type="ENUM('yes','no')">I'm using postgresql as my DBMS. is there anything like enum data type?
I've read in this like http://wiki.postgresql.org/wiki/Enum
我目前正在使用 liquibase.xml 文件来创建表 table_a。我的领域之一是<column name="state" type="ENUM('yes','no')">我使用 postgresql 作为我的 DBMS。有没有类似 enum 数据类型的东西？我读过这样的http://wiki.postgresql.org/wiki/Enum
that postgresql doesn't have such data type. CREATE TYPE function is used to create this data type. I still don't know how to make it in liquibase though.
postgresql 没有这样的数据类型。CREATE TYPE 函数用于创建此数据类型。我仍然不知道如何在 liquibase 中制作它。
Any suggestions?
有什么建议？
回答by a_horse_with_no_name
Well of course PostgreSQL has an enum type (which is clearly documented in the link you have shown and the manual).
当然，PostgreSQL 有一个枚举类型（在您显示的链接和手册中清楚地记录了这一点）。
I don't think Liquibase "natively" supports enums for PostgreSQL, but you should be able to achieve it with a custom SQL:
我不认为 Liquibase “本机”支持 PostgreSQL 的枚举，但您应该能够使用自定义 SQL 实现它：
<changeSet id="1" author="Arthur">
<sql>CREATE TYPE my_state AS ENUM ('yes','no')</sql>
<table name="foo">
<column name="state" type="my_state"/>
</table>
</changeSet>
For a simple yes/no column, I'd actually use the booleantype instead of an enum
对于一个简单的是/否列，我实际上会使用boolean类型而不是枚举
回答by mu is too short
An alternative to creating a new type would be a simple CHECK constraint on a varchar(3)column:
创建新类型的替代方法是对varchar(3)列进行简单的 CHECK 约束：
<changeSet id="1" author="X">
<table name="t">
<column name="c" type="varchar(3)"/>
</table>
<sql>ALTER TABLE t ADD CONSTRAINT check_yes_no CHECK (c = 'yes' OR c = 'no')</sql>
</changeSet>
That might play better with the client side, or not. I think boolean(as suggested by a_horse_with_no_name) would be a better call for this specific case: saying exactly what you mean usually works out better than the alternatives.
这可能在客户端玩得更好，或者不玩。我认为boolean（如 a_horse_with_no_name 所建议的）对于这种特定情况会更好：准确说出你的意思通常比替代方案更有效。
