Constraints for show table command in MySQL?-Mysql Tutorial-php.cn

Constraints for show table command in MySQL?

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Release： 2023-09-15 14:37:06

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在 MySQL 中显示表命令的约束？

You can display constraints on a table with the help of the SHOW command. The syntax is as follows -

show create table yourTableName;

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The above command will display all constraints of table ENGINE. Using it, you can even see all column names and corresponding data types.

To understand the above MySQL statement, let us first create a table -

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)

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Now you can apply the above syntax to display the constraints on the table. The query is as follows -

mysql> show create table ShowConstraintsDemo;

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The following is the output showing all constraints -

+---------------------+----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| 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)

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