所以MySQL只是check,但是不强制check。 1mysql>createtablecheckDemoTable(aint,bint,idint,primarykey(id));2Query OK,0rows affected34mysql>altertablecheckDemoTableaddconstraintcheckDemoConstraintcheck(a>0);5Query OK,0rows affected6Records:0Duplicates:0Warnings:078mysql>insertintocheckDemoTablevalues(-2,...
@param[in] trx_no transaction number to check with */ void reduce_low_limit(trx_id_t trx_no) { if (trx_no < m_low_limit_no) { /* Save low limit number set for Read View for MVCC. */ ut_d(m_view_low_limit_no = m_low_limit_no); m_low_limit_no = trx_no; } } /*...
# mysqlcheck[options] ---database DB1 [DB2 DB3...] #mysqlcheck[options] --all--database eg: [root@xuegod72 ~]# mysqlcheck -u root -p -c book books -检查表 Enter password: book.books OK [root@xuegod72 ~]# mysqlcheck -u root -p -r book --修复指定的数据库 Enter password: ...
AI代码解释 INSERTINTOuser(name,age)# 插入多行数据VALUES("Tim",19),("Lucy",16);---QueryOK,2rowsaffected(0.00sec)# 输出中的2row affected 代表已经成功插入了2行数据Records:2Duplicates:0Warnings:0# Records:2代表有2行数据要插入到表中 # Duplicates:0代表重复的行数是0# Warnings:0代表需要注意...
所以更改username字符集的操作没有成*** 清空users表中的数据 mysql> truncate table users; Query OK, 3 rows affected (0.01 sec) 从新更改user表中username的字符集 mysql> alter table users modify username char(20) character set gbk; Query OK, 0 rows affected (0.06 sec) Records: 0 Duplicates: ...
Records: 2 Duplicates: 0 Warnings: 0 4、查看master主机是否同步了slave上的数据变化 1. mysql> select * from tb1; 2. +---+---+ 3. | id | name | 4. +---+---+ 5. | 1 | z3 | 6. | 2 | l4 | 7. +---+---+ 8. 2 rows in set (0.01 sec) 通过查看master可以看到slav...
mysql所有的存储引擎均不支持check约束,MySQL会对check子句进行分析,但是在插入数据时会忽略,因此check并不起作用,因此实现对数据约束有两种方法: 1.在mysql种约束,如使用enum类型或者触发器等。 2.在应用程序里面对数据进行检查再插入。 五、用触发器代替check约束和关键字DELIMITER ...
Records: 0 Duplicates: 0 Warnings: 0 mysql> SHOW CREATE TABLE emoji_test\G *** 1. row *** Table: emoji_test Create Table: CREATE TABLE `emoji_test` ( `a` varchar(100) CHARACTER SET utf8mb4 COLLATE utf8mb4_0900_ai_ci NOT NULL, PRIMARY KEY (`a`) ) ENGINE=InnoDB DEFAULT CHARSE...
('Charlie', 35)") Query OK, 3 rows affected (0.0090 sec) Records: 3 Duplicates: 0 Warnings: 0 # 查询并打印记录 MySQL localhost:33060+ ssl Py > result = session.run_sql('SELECT * FROM users') MySQL localhost:33060+ ssl Py > print(result.fetch_all()) [[1, "Alice", 30], [2...
Bug #73170 Duplicates in Unique Secondary Index Because of Fix of Bug#68021 Submitted: 2 Jul 2014 7:26Modified: 4 Jul 2014 18:03 Reporter: Annamalai Gurusami Email Updates: Status: Closed Impact on me: None Category: MySQL Server: InnoDB storage engineSeverity: S2 (Serious) Version: ...