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
以上所述是小编给大家介绍的SQLSERVER实现更改表名，更改列名，更改约束代码，希望对大家有所帮助！
