CREATE TABLE parent ( id INT NOT NULL, PRIMARY KEY (id) ) ENGINE=INNODB; CREATE TABLE child ( id INT, parent_id INT, INDEX par_ind (parent_id), FOREIGN KEY (parent_id) REFERENCES parent(id) ) ENGINE=INNODB; Insert a row into the parent table, like this: ...
create table 表名( 字段名1 类型[(宽度) 约束条件], 字段名2 类型[(宽度) 约束条件], 字段名3 类型[(宽度) 约束条件] ); #注意: 1. 在同一张表中,字段名是不能相同 2. 宽度和约束条件可选 3. 字段名和类型是必须的mysql>create database db1 charset utf8; mysql>use db1; mysql>create table...
InnoDB supports multiple granularity locking which permits coexistence of row-level locks and locks on entire tables. To make locking at multiple granularity levels practical, additional types of locks called intention locks are used. Intention locks are table-level locks in InnoDB that indicate which ...
I'm trying to implement an inherited table into mySQL and i can't insert the 2nd FK (ignore the inheritance part, the priority is the FK problem). Does anyone know what the problem is here: CREATE TABLE Contacts ( `contact_ID` INT(10) UNSIGNED NOT NULL AUTO_INCREMENT, `contact...
已有的Insert锁不阻止任何准备加的锁。 5. 自增锁(AUTO-INC Locks) AUTO-INC锁是一种特殊的表级锁,发生涉及AUTO_INCREMENT列的事务性插入操作时产生。 官方解释如下[^3]: An AUTO-INC lock is a special table-level lock taken by transactions inserting into tables with AUTO_INCREMENT columns. In the ...
It is finally possible to fix the error with this method. Method 3: Check if there are any inappropriate quotes For every FOREIGN KEY declaration, ensure that no quotes are inserted around object qualifiers or that separate quotes surround the table and column names. ...
Insertion of a row into the child table with aparent_idvalue that is not present in the parent table is rejected with an error, as you can see here: mysql>INSERTINTOchild(id,parent_id)VALUESROW(2,2);ERROR 1452 (23000):Cannot add or update a child row:a foreign key constraint fails...
-- 创建数据库 CREATE DATABASE school_db; -- 切换数据库 USE school_db; -- 创建表 CREATE TABLE students ( id INT PRIMARY KEY AUTO_INCREMENT, name VARCHAR(50) NOT NULL, age INT CHECK (age >= 10), class_id INT, FOREIGN KEY (class_id) REFERENCES classes(id) ); -- 修改表结构 ALTER...
在事务内创建TEMPORARY TABLE或DROP TEMPORARY TABLE语句 更新事务和非事务表的事务或语句。 enforce_gtid_consistency仅在语句进行二进制日志记录时生效。如果在服务器上禁用了二进制日志记录,或者由于过滤器删除了语句而未将语句写入二进制日志,则不会对未记录的语句检查或强制执行GTID一致性。
CREATE TABLE T1(A INT PRIMARY KEY, B INT, C CHAR(1)) ENGINE=InnoDB; 代码语言:javascript 代码运行次数:0 运行 AI代码解释 INSERTINTOT1VALUES (1,2,'a'), (2,3,'b'), (3,2,'c'), (4,3,'d'), (5,2,'e');COMMIT;ALTERTABLET1ADDINDEX(B),ADDUNIQUEINDEX(C); ...