在 MySQL 中显示表命令的约束？

您可以借助 SHOW 命令显示表上的约束。语法如下 -

show create table yourTableName;登录后复制

为了理解上面的MySQL语句，让我们首先创建一个表 -

mysql> create table ShowConstraintsDemo    -> (    -> BookId int not null, -> BookName varchar(200) not null, -> BookAuthor varchar(200) Unique not null, -> Primary key(BookId,BookName) -> ); Query OK, 0 rows affected (1.04 sec)登录后复制

mysql> show create table ShowConstraintsDemo;登录后复制

+---------------------+----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+ | Table                | Create Table                                                                                                                                                                                                                            | +---------------------+----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+ | ShowConstraintsDemo | CREATE TABLE `showconstraintsdemo` ( `BookId` int(11) NOT NULL, `BookName` varchar(200) COLLATE utf8mb4_unicode_ci NOT NULL, `BookAuthor` varchar(200) COLLATE utf8mb4_unicode_ci NOT NULL, PRIMARY KEY (`BookId`,`BookName`), UNIQUE KEY `BookAuthor` (`BookAuthor`) ) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_unicode_ci          | +---------------------+----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+ 1 row in set (0.05 sec)登录后复制