if exists(select * from sysobjects where name=约束名) alter table 表名 drop constraint 约束名; go alter table 表名 add constraint 约束名 check(约束规则),constraint 约束名 check(约束规则); go 示例: -- 添加一个默认约束 use testss; go if exists(select * from sysobjects where name='check1...
IF EXISTS (SELECT * FROM dbo.sysobjects WHERE id = OBJECT_ID(N'[dbo].[Carl]') AND OBJECTPROPERTY(id, N'IsUserTable') = 1) DROP TABLE [dbo].[Carl] Create Table Carl ( InCarlID int --Unique --创建表时创建唯一约束 ) --在已有的表中创建唯一约束 Alter Table Carl Add Constraint UC...
it returns theobject ID; otherwise, it returnsNULL. We can use theCOALESCE()function to convert this result into a boolean value. However,this approach returnstrueif any database object with that name exists in the schema, not just a table. ...
How to check if a table exists in any of the databases in a server ? For example, I want to see if a table called userAccountsBackup exists in any of the 25 databases in a server. How can I write a query to find this ?
We want to know if an index named ix_halp exists on the table agg.FirstNameByYear in theSQLIndexWorkbook database– now renamed to BabbyNames. It does! It was created with this code: CREATENONCLUSTEREDINDEXix_halpONagg.FirstNameByYear (ReportYear) ...
SQL Server/Oracle/MS Access: CREATE TABLE Persons ( P_Id int NOT NULL CHECK(P_Id>0), LastName varchar(255) NOT NULL, FirstName varchar(255), Address varchar(255), City varchar(255) ) 如需命名CHECK约束,并定义多个列的CHECK 约束,使用下面的SQL语法: ...
IF EXISTS (SELECT 1 FROM sys.fulltext_catalogs WHERE [name] = 'AW2008FullTextCatalog') PRINT 'Catalog exists' ELSE PRINT 'Catalog does not exists'; I hope it helps. J. There are 10 type of people. Those who understand binary and those who do not. ...
SQL Query to return the dataSELECT TABLE_NAME FROM DBName.INFORMATION_SCHEMA.Tables WHERE TABLE_NAME='Article' How do I check this in C#?As for how you check that in C#? You just make sure the Row count returned from the query is 1. See this article I have already posted. How do ...
if quorum is lost then all cluster resources including AGs in this partition are taken offline. All nodes in this partition are transitioned to a resolving state. If a partition exists, which holds a quorum, the AG is assigned to one node in the partition and becomes the pr...
check_if_table_exists() This assert was triggered when the server tried to load plugins while running in embedded server mode. In embedded server mode, check_if_table_exists() was used to check if mysql.plugin existed so that ER_NO_SUCH_TABLE could be silently ignored. The problem was ...