PRIMARY KEY(stu_id,course_id) ); 1. 2. 3. 4. 5. 6. 此时stu_id和course_id可以唯一确定一条记录 - ### 外键表示FOREIGN KEY: 基本语法规则: CONSTRAINT 外键别名 FOREIGN KEY(属性1.1,属性1.2,...属性1.n) REFERENCES 表名(属性2.1,属性2.2,...,属性2.n) 1. (具体说明见MySQL入门很简单P81...
show create table ; ...will show the exact create command issued, but if you are asking us to play the parsing game to get the foreign key column then you missed them point. [1 Jun 2013 1:49] MySQL User Seriously though... This needs to be implemented....
1.主键:每个表中最多只能有1个主键,且主键的值不能重复,通过主键可以唯一的确定一条记录。当我们在创建表的时候就声明了主键的话,Mysql就会对我们插入的每一条记录进行检验,若有主键值相同时就会报错。另外主键是默认NotNull的。 声明主键的两种方式: 主键只是单个列时(比如设置学生的学号为主键): Stu_id int(...
UNIQUEKEY`name`(`name`), KEY`deptId`(`deptId`), CONSTRAINT`tb_emp8_ibfk_1`FOREIGNKEY(`deptId`)REFERENCES`tb_dept1`(`id`) )ENGINE=InnoDBDEFAULTCHARSET=gb2312 1rowinset(0.19sec) 扩展知识: 外键约束的定义 Mysql外键约束(FOREIGN KEY)是表的一个特殊字段,经常与主键约束一起使用。对于两个具有关联...
mysql> SHOW DATABASES; SHOW TABLES – 显示当前数据库中所有表的名称(需要设置默认数据库use DATABASE_NAME) Mysql> SHOW TABLES; SHOW TABLES FROM db_name – 显示数据库中的所有表 Mysql> SHOW TABLES FROM db_name; SHOW ENGINES - 显示MySQL当前支持哪些存储引擎和默认存储引擎 ...
trx_foreign_key_checks: 1 trx_last_foreign_key_error: NULL trx_adaptive_hash_latched: 0 trx_adaptive_hash_timeout: 10000 1 row in set (0.00 sec) -- 此时没有发生锁等待,故 innodb_locks表 和 innodb_lock_waits 表都没有数据。 mysql> SELECT * FROM information_schema.innodb_locks G ...
| InnoDB | DEFAULT | Supports transactions, row-level locking, and foreign keys |YES|YES|YES| | FEDERATED |NO| Federated MySQL storage engine |NULL|NULL|NULL| +---+---+---+---+---+---+ mysql>showgrants; mysql>showgrantsforcurrent_user;+---...
mysql> show authors\G; *** 1. row *** Name: Brian (Krow) Aker Location: Seattle, WA, USA Comment: Architecture, archive, federated, bunch of little stuff :) *** 2. row *** Name: Venu Anuganti Location: Comment: Client/server...
课程 /数据库 /MySQL /与MySQL的零距离接触 SHOW CREATE TABLE provices;//查看数据表的属性; FOREIGN KEY外键的作用: 引用外部数据表, 外键要求:数据类型相似; 有外键的表是:子表, 没有外键,被引用的表,是主表; 语法: FOREIGN KEY (pid) REFERENCES provinces(id) 明君 2014-09-04 源自:与MySQL的零...
The only other thing I can imagine is that PHPMyAdmin generated an SQL_MODE setting in its export output and I used that. While I haven't done that for some time, it's possible that a setting might have been hanging around and then, when I restarted mysqld today after a system crash...