步骤1:检查CONSTRAINT是否存在 在执行删除操作之前,首先要检查CONSTRAINT是否存在。 -- 检查CONSTRAINT是否存在IFEXISTS(SELECT*FROMINFORMATION_SCHEMA.TABLE_CONSTRAINTSWHERECONSTRAINT_NAME='CONSTRAINT_NAME'ANDTABLE_NAME='TABLE_NAME')BEGINPRINT'CONSTRAINT存在,可以删除'ENDELSEBEGINPRINT'CONSTRAINT不存在'END 1. 2. 3...
IF EXISTS(SELECT * FROM sysobjects WHERE name='student') DROP TABLE student --检查student是否已经存在,如果存在,则删除 GO CREATE TABLE student --表名为student ( StuID int NOT NULL, --学生学号 StuName varchar(15) UNIQUE NOT NULL, --学生姓名 Sex char(2) NULL, --性别 Major varchar(20) ...
ALTER TABLE 测试表 ADD CONSTRAINT 默认约束1 DEFAULT ('默认设置值') FOR 字段名 --判断是否存在主键约束,primary key简称PK是主键约束的type--- IF EXISTS(SELECT * FROM sysobjects WHERE name='约束条件名称' and xtype='PK') begin print '存...
IF COL_LENGTH( '表名','列名') IS NULL PRINT 'not exists' ELSE PRINT 'exists' alter table 表名drop constraint 默认值名称 go alter table 表名drop column 列名 go --- --判断要创建临时表是否存在 If Object_Id('Tempdb.dbo.#Test') Is Not Null Begin print '存在' End Else Begin...
I don't like these, and if you also don't like them, then you might try new DROP IF EXISTS (a.k.a. DIE :) ) statements in SQL Server 2016.From SQL Server 2016 CTP3 you can use new DIE statements instead of big IF wrappers, e.g.:...
go:官方说法是:GO只是SQL Server管理器(SSMS)中用来提交T-SQL语句的一个标志。我的理解是,go为SQL语句的结束标志,它可以将多条SQL语句进行分割,互不关联。 2.添加T_product商品表: ifexists(select*fromsysobjectswherename='T_product')begin...endelsebegincreatetableT_product--创建表( ....
DROPPROCEDUREIFEXISTSusp_CleanupHistoryData; GOCREATEPROCEDUREusp_CleanupHistoryData @temporalTableSchema SYSNAME, @temporalTableName SYSNAME, @cleanupOlderThanDate DATETIME2ASDECLARE@disableVersioningScriptNVARCHAR(MAX) ='';DECLARE@deleteHistoryDataScriptNVARCHAR(MAX) ='';DECLARE@...
If the object does not exists, DIE will not fail and execution will continue. Currently, the following objects can DIE: DIE is added on columns and constraints in ALTER TABLE statement ALTER TABLE DROP COLUMN IF EXISTS ALTER TABLE DROP CONSTRAINT IF EXISTS ...
/* Disable resource governor so that the classifier function can be dropped. */ALTERRESOURCEGOVERNORDISABLE;ALTERRESOURCEGOVERNORWITH(CLASSIFIER_FUNCTION =NULL);DROPFUNCTIONIFEXISTSdbo.rg_classifier;DROPTABLEIFEXISTSdbo.workload_interval;/* Drop the workload groups. This requires that no sessions are ...
--Generate ALTER DATABASE ... MODIFY FILEGROUP statements--so that all read-write filegroups grow at the same time.SETNOCOUNTON;DROPTABLEIFEXISTS#tmpdbsCREATETABLE#tmpdbs (idINTIDENTITY(1,1), [dbid]INT, [dbname] sysname, isdoneBIT);DROPTABLEIFEXISTS#tmpfgsCREATETABLE#tmpfgs (idINTIDENTITY...