在已创建的表中更改SQL数据库 [英] Alter SQL database in already created table
本文介绍了在已创建的表中更改SQL数据库的处理方法,对大家解决问题具有一定的参考价值,需要的朋友们下面随着小编来一起学习吧!
问题描述
I want to alter my already created table in sql sever 2005
推荐答案
使用 ALTER TABLE命令 [ ^ ]。
嗨朋友,
在Google或MSDN上查看DDL(数据定义) Langauage)...
数据定义语言(DDL)语句(Transact-SQL) [ ^ ]
问候,
GVPrabu
Hi Friend,
Check in Google or MSDN for DDL (Data Definition Langauage)...
Data Definition Language (DDL) Statements (Transact-SQL)[^]
Regards,
GVPrabu
示例:
CREATE TABLE dbo.Employee
(
EmployeeID INT IDENTITY(1,1)NOT NULL
,FirstName VARCHAR(50)NULL
,MiddleName VARCHAR(50)NULL
,LastName VARCHAR(50)NULL
,DateHired datetime NOT NULL
)
- 更改数据类型以支持100个字符并使NOT NULL
ALTER TABLE dbo.Employee
ALTER COLUMN FirstName VARCHAR(100)NOT NULL
- 更改数据类型并允许DateHired为NULL
ALTER TABLE dbo.Employee
ALTER COLUMN DateHired SMALLDATETIME NULL
- 为中间名设置SPARSE列(仅限sql server 2008) )
ALTER TABLE dbo.Employee
ALTER COLUMN MiddleName VARCHAR(100)SPARSE NULL
Example:
CREATE TABLE dbo.Employee
(
EmployeeID INT IDENTITY (1,1) NOT NULL
,FirstName VARCHAR(50) NULL
,MiddleName VARCHAR(50) NULL
,LastName VARCHAR(50) NULL
,DateHired datetime NOT NULL
)
-- Change the datatype to support 100 characters and make NOT NULL
ALTER TABLE dbo.Employee
ALTER COLUMN FirstName VARCHAR(100) NOT NULL
-- Change datatype and allow NULLs for DateHired
ALTER TABLE dbo.Employee
ALTER COLUMN DateHired SMALLDATETIME NULL
-- Set SPARSE columns for Middle Name (sql server 2008 only)
ALTER TABLE dbo.Employee
ALTER COLUMN MiddleName VARCHAR(100) SPARSE NULL
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