如何使用检查约束更改 table - SQL 服务器

How to do alter table using Check Constraint - SQL Server

CREATE TABLE publishers
(
    PublisherName    varchar(75),
    City                    varchar(35),
    PublisherState    char(2),
    Country            varchar(4)
)
GO 

-- 修改publishers,使state必须是两个字母

ALTER TABLE publishers
    ALTER COLUMN publisherstate char(2) CHECK (publisherstate LIKE '[A-Za-z][A-Za-z]')​

你不得不提到 Constraint NameCheck

试试这个:

alter table publishers
add constraint codeCheck check (PublisherState like '[A-Za-z][A-Za-z]');