一个改表结构的问题! alter table yourtable (newid bigint primary key) 解决方案 » 免费领取超大流量手机卡,每月29元包185G流量+100分钟通话, 中国电信官方发货 ALTER TABLE通过更改、添加、除去列和约束,或者通过启用或禁用约束和触发器来更改表的定义。语法ALTER TABLE table { [ ALTER COLUMN column_name { new_data_type [ ( precision [ , scale ] ) ] [ COLLATE < collation_name > ] [ NULL | NOT NULL ] | {ADD | DROP } ROWGUIDCOL } ] | ADD { [ < column_definition > ] | column_name AS computed_column_expression } [ ,...n ] | [ WITH CHECK | WITH NOCHECK ] ADD { < table_constraint > } [ ,...n ] | DROP { [ CONSTRAINT ] constraint_name | COLUMN column } [ ,...n ] | { CHECK | NOCHECK } CONSTRAINT { ALL | constraint_name [ ,...n ] } | { ENABLE | DISABLE } TRIGGER { ALL | trigger_name [ ,...n ] } }< column_definition > ::= { column_name data_type } [ [ DEFAULT constant_expression ] [ WITH VALUES ] | [ IDENTITY [ ( seed , increment ) [ NOT FOR REPLICATION ] ] ] ] [ ROWGUIDCOL ] [ COLLATE < collation_name > ] [ < column_constraint > ] [ ...n ]< column_constraint > ::= [ CONSTRAINT constraint_name ] { [ NULL | NOT NULL ] | [ { PRIMARY KEY | UNIQUE } [ CLUSTERED | NONCLUSTERED ] [ WITH FILLFACTOR = fillfactor ] [ ON { filegroup | DEFAULT } ] ] | [ [ FOREIGN KEY ] REFERENCES ref_table [ ( ref_column ) ] [ ON DELETE { CASCADE | NO ACTION } ] [ ON UPDATE { CASCADE | NO ACTION } ] [ NOT FOR REPLICATION ] ] | CHECK [ NOT FOR REPLICATION ] ( logical_expression ) }< table_constraint > ::= [ CONSTRAINT constraint_name ] { [ { PRIMARY KEY | UNIQUE } [ CLUSTERED | NONCLUSTERED ] { ( column [ ,...n ] ) } [ WITH FILLFACTOR = fillfactor ] [ ON { filegroup | DEFAULT } ] ] | FOREIGN KEY [ ( column [ ,...n ] ) ] REFERENCES ref_table [ ( ref_column [ ,...n ] ) ] [ ON DELETE { CASCADE | NO ACTION } ] [ ON UPDATE { CASCADE | NO ACTION } ] [ NOT FOR REPLICATION ] | DEFAULT constant_expression [ FOR column ] [ WITH VALUES ] | CHECK [ NOT FOR REPLICATION ] ( search_conditions ) }参数new_data_type是要更改的列的新数据类型。要更改的列的 new_data_type 应符合下列准则: 原来的数据类型必须可以隐式转换为新数据类型。new_data_type 类型不能为 timestamp。对 ALTER COLUMN,ANSI 空默认值始终打开;如果没有指定,列将可为空。对 ALTER COLUMN,ANSI 填充始终打开。如果要更改的列是标识列,new_data_type 必须是支持标识属性的数据类型。将忽略 SET ARITHABORT 的当前设置。ALTER TABLE 语句的行为如同 ARITHABORT 选项为 ON 时一样。 chenyuandxm(一剑平江湖:不行,我刚才试了不行,能不能说得明白一点. 安装问题 在用GridView导入数据库表时,怎么修改原来的精度? visio2003 画图问题 为什么要进行关系模式分解?分解的依据是什么? 继续问一个查询问题? 求触发器语句。 请问:如何对Group by 出来的数据进行 Inner Join 求教一条语句的写法 请问如何通过SQL查询一个数据库中所有表的名称? sql server中如何用“触发器”实现自动增量?, 求一SQL语句? 征集DBF导入软件方案
通过更改、添加、除去列和约束,或者通过启用或禁用约束和触发器来更改表的定义。语法
ALTER TABLE table
{ [ ALTER COLUMN column_name
{ new_data_type [ ( precision [ , scale ] ) ]
[ COLLATE < collation_name > ]
[ NULL | NOT NULL ]
| {ADD | DROP } ROWGUIDCOL }
]
| ADD
{ [ < column_definition > ]
| column_name AS computed_column_expression
} [ ,...n ]
| [ WITH CHECK | WITH NOCHECK ] ADD
{ < table_constraint > } [ ,...n ]
| DROP
{ [ CONSTRAINT ] constraint_name
| COLUMN column } [ ,...n ]
| { CHECK | NOCHECK } CONSTRAINT
{ ALL | constraint_name [ ,...n ] }
| { ENABLE | DISABLE } TRIGGER
{ ALL | trigger_name [ ,...n ] }
}< column_definition > ::=
{ column_name data_type }
[ [ DEFAULT constant_expression ] [ WITH VALUES ]
| [ IDENTITY [ ( seed , increment ) [ NOT FOR REPLICATION ] ] ]
]
[ ROWGUIDCOL ]
[ COLLATE < collation_name > ]
[ < column_constraint > ] [ ...n ]< column_constraint > ::=
[ CONSTRAINT constraint_name ]
{ [ NULL | NOT NULL ]
| [ { PRIMARY KEY | UNIQUE }
[ CLUSTERED | NONCLUSTERED ]
[ WITH FILLFACTOR = fillfactor ]
[ ON { filegroup | DEFAULT } ]
]
| [ [ FOREIGN KEY ]
REFERENCES ref_table [ ( ref_column ) ]
[ ON DELETE { CASCADE | NO ACTION } ]
[ ON UPDATE { CASCADE | NO ACTION } ]
[ NOT FOR REPLICATION ]
]
| CHECK [ NOT FOR REPLICATION ]
( logical_expression )
}< table_constraint > ::=
[ CONSTRAINT constraint_name ]
{ [ { PRIMARY KEY | UNIQUE }
[ CLUSTERED | NONCLUSTERED ]
{ ( column [ ,...n ] ) }
[ WITH FILLFACTOR = fillfactor ]
[ ON { filegroup | DEFAULT } ]
]
| FOREIGN KEY
[ ( column [ ,...n ] ) ]
REFERENCES ref_table [ ( ref_column [ ,...n ] ) ]
[ ON DELETE { CASCADE | NO ACTION } ]
[ ON UPDATE { CASCADE | NO ACTION } ]
[ NOT FOR REPLICATION ]
| DEFAULT constant_expression
[ FOR column ] [ WITH VALUES ]
| CHECK [ NOT FOR REPLICATION ]
( search_conditions )
}参数
new_data_type是要更改的列的新数据类型。要更改的列的 new_data_type 应符合下列准则: 原来的数据类型必须可以隐式转换为新数据类型。
new_data_type 类型不能为 timestamp。
对 ALTER COLUMN,ANSI 空默认值始终打开;如果没有指定,列将可为空。
对 ALTER COLUMN,ANSI 填充始终打开。
如果要更改的列是标识列,new_data_type 必须是支持标识属性的数据类型。
将忽略 SET ARITHABORT 的当前设置。ALTER TABLE 语句的行为如同 ARITHABORT 选项为 ON 时一样。
不行,我刚才试了不行,能不能说得明白一点.