MySQL 我们可以使用PRIMARY KEY(column1,column2)来生成键值对吗?
是的,你可以使用以下语法。以下是语法 –
PRIMARY KEY(yourColumnName1,yourColumnName2);
让我们首先创建一个表 –
mysql> create table DemoTable
-> (
-> StudentFirstName varchar(100),
-> StudentLastName varchar(100),
-> StudentAge int,
-> StudentCountryName varchar(100),
-> PRIMARY KEY(StudentFirstName,StudentLastName)
-> );
Query OK,0 rows affected (0.74 sec)
让我们检查表的描述 –
mysql> desc DemoTable;
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输出
这将产生以下输出-
+--------------------+--------------+------+-----+---------+-------+
| Field | Type | Null | Key | Default | Extra |
+--------------------+--------------+------+-----+---------+-------+
| StudentFirstName | varchar(100) | NO | PRI | NULL | |
| StudentLastName | varchar(100) | NO | PRI | NULL | |
| StudentAge | int(11) | YES | | NULL | |
| StudentCountryName | varchar(100) | YES | | NULL | |
+--------------------+--------------+------+-----+---------+-------+
4 rows in set (0.00 sec)
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