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这篇文章主要介绍了SQLSERVER实现更改表名,更改列名,更改约束代码的相关资料,需要的朋友可以参考下
废话不多说了,具体详情如下所示:
1.修改表名
格式:sp_rename tablename,newtablename
- sp_rename tablename,newtablename
2.修改字段名
格式:sp_rename 'tablename.colname',newcolname,'column'
- sp_rename 'tablename.colname',newcolname,'column'
3.添加字段
格式:alter table table_name add new_column data_type [interality_codition]
示例1
- ALTER TABLE student Add nationality varchar(20)
--示例2 添加int类型的列,默认值为 0
- alter table student add studentName int
- default 0--示例3添加int类型的列,
- 默认值为0,主键alter table student add studentId int primary key
- default 0--示例4判断student中是否存在name字段且删除字段
- if exists(select * from syscolumns where id = object_id('student') and name = 'name') begin alter table student DROP COLUMN name end
4.更改字段
格式:alter table table_name alter column column_name
- ALTER TABLE student ALTER COLUMN name VARCHAR(200)
5.删除字段
格式:alter table table_name drop column column_name
- ALTER TABLE student DROP COLUMN nationality;
6.查看字段约束
格式: select * from information_schema.constraint_column_usage where TABLE_NAME = table_name
- SELECT TABLE_NAME,COLUMN_NAME,CONSTRAINT_NAME FROM information_schema.CONSTRAINT_COLUMN_USAGE
- WHERE TABLE_NAME = 'student'
7.查看字段缺省约束表达式 (即默认值等)
格式:select * from information_schema.columns where TABLE_NAME = table_name
- SELECT TABLE_NAME, COLUMN_NAME, COLUMN_DEFAULT FROM information_schema.COLUMNS
- WHERE TABLE_NAME='student'
8.查看字段缺省约束名
格式:select name from sysobjects where object_id(table_name)=parent_obj and xtype='D'
- select name from sysobjects
- where object_id('表?名?')=parent_obj and xtype='D'
9.删除字段约束
格式:alter table tablename drop constraint constraintname
- ALTER TABLE student DROP CONSTRAINT PK__student__2F36BC5B772B9A0B
10.添加字段约束
格式:alter table tablename add constraint constraintname primary key (column_name)
--示例1
- ALTER TABLE stuInfo ADD CONSTRAINT PK_stuNo PRIMARY KEY (stuNo) --示例2 添加主键约束(Primary Key)
- -- 存在主键约束PK_stuNO,则删除
- IF EXISTS(SELECT * FROM sysobjects WHERE name='PK_stuNo' and xtype='PK')
- Alter TABLE stuInfo
- Drop Constraint PK_stuNo
- Go -- 重新添加主键约束PK_stuNO
- ALTER TABLE stuInfo ADD CONSTRAINT PK_stuNo PRIMARY KEY (stuNo)
- Go --示例3 添加 唯一UQ约束(Unique Constraint)
- -- 存在唯一约束UQ_stuNO,则删除
- IF EXISTS(SELECT * FROM sysobjects WHERE name='UQ_stuID' and xtype='UQ')
- Alter TABLE stuInfo
- Drop Constraint UQ_stuID
- Go
- -- 重新添加唯一约束UQ_stuID
- ALTER TABLE stuInfo ADD CONSTRAINT UQ_stuID UNIQUE (stuID) --示例4 添加默认DF约束(Default Constraint)
- -- 存在默认约束UQ_stuNO,则删除
- IF EXISTS(SELECT * FROM sysobjects WHERE name='DF_stuAddress' and xtype='D')
- Alter TABLE stuInfo Drop Constraint DF_stuAddress
- Go -- 重新添加默认约束DF_stuAddress
- ALTER TABLE stuInfo ADD CONSTRAINT DF_stuAddress DEFAULT ('地址不详') FOR stuAddress --示例5 检查CK约束(Check Constraint)
- -- 存在检查约束UQ_stuNO,则删除
- IF EXISTS(SELECT * FROM sysobjects WHERE name='CK_stuAge' and xtype='C')
- Alter TABLE stuInfo Drop Cons
来源: http://www.phperz.com/article/17/0914/348797.html