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...
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.:...
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( ....
--关闭游标CLOSEc_test_main;--释放游标.DEALLOCATEc_test_main;END;if@delfield=1begin--判断表是否存在--if exists (select 1 from sys.tables where name=@tbname and type = 'u')--判断列是否存在IFCOL_LENGTH(@tbname,@fdname)ISnotNULLexec('alter table ['+@tbname+'] drop column ['+@fd...
SQL Server 的语法(文件组和文件流以外的所有选项都适用于Azure SQL 数据库)。 syntaxsql DROPINDEX[IFEXISTS] {<drop_relational_or_xml_or_spatial_index>[ , ...n ] |<drop_backward_compatible_index>[ , ...n ] }<drop_relational_or_xml_or_spatial_index>::=index_nameON[WITH(<drop_clustered...
/* 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 ...
3 - SQL Server 2008 之 使用SQL语句删除约束条件 基本语法为: ALTER TABLE 表名 DROP CONSTRAINT 约束名1,约束名2…… 如果删除一个约束,不需要逗号后的约束名,如果删除两个及两个以上的约束,必须以逗号隔开。...使用上一节中的Employee表,删除Employee表中的FK_PersonID外键约束及PK_EmployeeID主键约束,其代...