Show constraints on table command in MySQL?

You can show constraints on tables with the help of SHOW command. The syntax is as follows −

show create table yourTableName;

The above command will show all constraints with table ENGINE. Using this, you can even see all the 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)

Now you can apply the above syntax in order to show constraints on tables. The query is as follows −

mysql> show create table ShowConstraintsDemo;

The following is the output that displays all the 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)