为INSERT 和 UPDATE 语句禁用 CHECK 约束在“对象资源管理器” 中,连接到 数据库引擎的实例。 在标准菜单栏上,单击 “新建查询”。 将以下示例复制并粘贴到查询窗口中,然后单击 “执行”。 SQL 复制 USE AdventureWorks2022; GO ALTER TABLE Purchasing.PurchaseOrderHeader NOCHECK CONSTRAINT CK_...
SQL进阶第一章---CASE表达式之CHECK约束 & 使用CASE表达式在Update语句里面进行条件分支 用CHECK约束定义多个列的条件关系 假设某个公司规定“女性员工的工资必须是在20万日元以下”,不得不说句这个规定真是太TM不合理了,在这个公司的人事表中,这条物理的规定是使用CHECK约束来描述的。 CONSTRAINTcheck_salaryCHECK(CA...
Alter table dept50 add constraint dept50_fk foreign key(d_id) references dept60(id); 1. 2. 3. 4. 5. 六、定义check约束 创建表时定义check约束 例 创建dept30表,包括ID、薪水,薪水不能小于1000,并自定义名字; Create table dept30(id number , salary number(8,2) , constraint dept30_ck ...
SQL 复制 USE AdventureWorks2022; GO BEGIN TRANSACTION; BEGIN TRY -- Intentionally generate a constraint violation error. UPDATE HumanResources.Department SET Name = N'MyNewName' WHERE DepartmentID BETWEEN 1 AND 2; END TRY BEGIN CATCH SELECT ERROR_NUMBER() AS ErrorNumber ,ERROR_SEVERITY() AS...
on update set null 从mysql4.0.13开始，允许同一个表上的on delete set null 从mysql4.0.21开始，允许同一个表上的on delete cascade 但级联层次不能超出15 3, Innodb在检查unique,constraint约束时，是row by row而不是语句或事务结束;SQL标准中对constraint的检查是在语句执行完成时 ...
CHECK COLLATE COLUMN CONDITION CONNECTION CONSTRAINT CONTINUE CONVERT CREATE CROSS CURRENT_DATE CURRENT_TIME CURRENT_TIMESTAMP CURRENT_USER CURSOR DATABASE DATABASES DAY_HOUR DAY_MICROSECOND DAY_MINUTE DAY_SECOND DEC DECIMAL DECLARE DEFAULT DELAYED DELETE ...
SQL 复制 USE AdventureWorks2022; GO BEGIN TRANSACTION; BEGIN TRY -- Intentionally generate a constraint violation error. UPDATE HumanResources.Department SET Name = N'MyNewName' WHERE DepartmentID BETWEEN 1 AND 2; END TRY BEGIN CATCH SELECT ERROR_NUMBER() AS ErrorNumber ,ERROR_SEVERITY() AS...
CaveDwellers ( Num INT UNIQUE, CaveCluster CHAR(80) NOT NULL, Troglodyte CHAR(50) NOT NULL, CONSTRAINT CaveDwellerPK PRIMARY KEY (Num) ) ) if SQLCODE = 0 { w !,"表创建" } elseif SQLCODE = -201 { w !,"表已经存在" } else { w !,"SQL表创建错误代码: ",SQLCODE q } } 下面的...
procsql;createtablework.employees /*将限制条件直接跟在变量后*/(IDchar(5)primarykey, Namechar(10), Genderchar(1)notnullcheck(genderin('M','F')), HDate date label='Hire Date'); Creating a Constraint by Using a Constraint Specification ...
For more information, see FILESTREAM (SQL Server). Error handling If an update to a row violates a constraint or rule, violates the NULL setting for the column, or the new value is an incompatible data type, the statement is canceled, an error is returned, and no records are updated. ...