https://www.linjiangxiong.com/2019/10/12/mysql-auto-increment-id/ 1. 2. link 总结 1.违反唯一键约束,事务回滚和批量插入数据,会造成数据自增主键不连续的情况。 2.在生产上,尤其是有 insert … select ;replace … select 和 load data语句这种批量插入数据的场景时,从并发插入数据性能的角度考虑, 我...
创建表并添加默认约束的示例代码 CREATETABLEemployees(idINTAUTO_INCREMENTPRIMARYKEY,nameVARCHAR(100)NOTNULL,statusENUM('active','inactive')DEFAULT'active'); 1. 2. 3. 4. 5. 解释:在这个示例中,我们创建了一个employees表,其中id是主键,name是员工的名字,类型为字符串,不允许为空。而status字段为枚举类型...
sql_table.cc::mysql_alter_table(); //判断当前操作是否可以进行Inplace实现,不可进行Inplace Alter的包括: // 1. Auto Increment字段修改; // 2.列重命名; // 3.行存储格式修改;等 mysql_compare_tables() -> ha_innobase::check_if_incompatible_data(); // Inplace创建索引第一阶段(主要阶段) han...
Suppose you have a table with non-numeric fields and you want to add auto-increment column with a prefix (such as 'ccs1'). This is how you will do it. For ease of understanding, I'm creating the table also. create table demo(id varchar(10),nme varchar(10)); You then need ...
mysql修改已存在的表增加ID属性为auto_increment自动增长 今天有需要将已经存在表设置自动增长属性 具体如下 alter table customers change id id int not null auto_increment primary key; //添加字段并设置主键 ALTER TABLE tabelname ADD new_field_id int(5) unsigned default 0 not null auto_increment ,ADD...
mysql> use mydb;mysql> CREATE TABLE mytable (id INT NOT NULL AUTO_INCREMENT PRIMARY KEY, name VARCHAR(50), age INT) ENGINE=TokuDB;mysql> quit;4. 测试TokuDB存储引擎：mysql -u root -p mysql> use mydb;mysql> INSERT INTO mytable (name, age) VALUES (‘John Doe&#...
AUTO_INCREMENT PRIMARY KEY; SELECT * FROM t1 ORDER BY id; save_master_pos; connection slave; sync_with_master; SELECT * FROM t1 ORDER BY id; connection master; drop table t1; save_master_pos; connection slave; sync_with_master; ALTER TABLE t1 ADD id int(8) ZEROFILL AUTO_INCREMENT ...
我想要往 job 表中 insert 一条数据,报错如题。 原因:要插入 job 表的数据中外键列的值有问题,userId 字段的值在 user 表中找不到。 解决: 确保 job 表中要引用的外键值在 user 表中有对应数据就可以了。 “ you're adding a foreign key, you need to make sure that the data in the child tabl...
写给新手的Mysql入门指南(二) ALTER TABLE t1 ADD id SMALLINT UNSIGNED AUTO_INCREMENT PRIMARY KEY FIRST; 添加多列,ALTER TABLE table_name...添加默认约束 ALTER TABLE tablename ALTER col_name SET DEFAULT 默认值; 给t1表的age字段添加默认值 ALTER TABLE t1 ALTER age...SET DEFAULT 20; 删除默...
After work, I find a solution, I used a variable with an himself autoincrement and I concat it with an other field. The code is : SET @RowNum=0; SELECT @RowNum:=@RowNum + 1, CONCAT_WS('_', T_Cmde_BaseNumCle2, Convert(@RowNum, Char(7))) from t_jp_commande; ...