在postgresql中添加一对一的非空约束

发布时间：2020-12-13 16:28:30 所属栏目：百科来源：网络整理

导读：如果我在Postgresql中有一个表： create table Education ( id integer references Profiles(id),finished YearValue not null,started YearValue,qualification text,schoolName text,studiedAt integer references Organizations(id),primary key (id));

如果我在Postgresql中有一个表：

create table Education ( 
    id                  integer references Profiles(id),finished            YearValue not null,started             YearValue,qualification       text,schoolName          text,studiedAt           integer references Organizations(id),primary key (id)
);

我需要做一个约束,以使schoolName或studyingAt不需要为空(其中一个必须有信息).

我该如何做？

您可以使用 check constraint

constraint chk_education check (schoolName is not null or studiedAt is not null)

从手册：

A check constraint is the most generic constraint type. It allows you to specify that the value in a certain column must satisfy a Boolean (truth-value) expression.

编辑：替代遵守无形式解释：

constraint chk_education check ((schoolName is not null and studiedAt is null) or (schoolName is null and studiedAt is not null))

（编辑：李大同）

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