delphi中使用sql2000数据库，如何增加一个表和在现有表中增加字段 ( 积分: 50 )

delphi中使用sql2000数据库，如何增加一个表和在现有表中增加字段，要先判断有没有这个表，没有就增加，有没有这个字段，没有就增加，请给出代码

if&nbsp;exists&nbsp;(select&nbsp;*&nbsp;from&nbsp;dbo.sysobjects&nbsp;where&nbsp;id&nbsp;=&nbsp;object_id(N'[dbo].[MyTable]')&nbsp;and&nbsp;OBJECTPROPERTY(id,&nbsp;N'IsUserTable')&nbsp;=&nbsp;1)<br>begin<br>&nbsp;&nbsp;alter&nbsp;table&nbsp;[dbo].[MyTable]&nbsp;add&nbsp;&quot;Name&quot;&nbsp;[varchar]&nbsp;(30)&nbsp;NULL<br>end<br>else<br>begin<br>&nbsp;&nbsp;CREATE&nbsp;TABLE&nbsp;[dbo].[MyTable]&nbsp;(<br>&nbsp;&nbsp;&nbsp;&nbsp;[ID]&nbsp;[int]&nbsp;NOT&nbsp;NULL,<br>&nbsp;&nbsp;&nbsp;&nbsp;[Name]&nbsp;[varchar]&nbsp;(30)&nbsp;NULL<br>&nbsp;&nbsp<br>end

楼上以给出代码

帮你顶

二楼标准写法

如果新建的数据库是名是syjxc,表名是show1,域名是n_code,n_code&nbsp;varchar&nbsp;3,不用except能给出具体的例子把

creation-zy大侠已写，<br>我再补充点:<br>也可以这么写<br>if&nbsp;exists(select&nbsp;*&nbsp;from&nbsp;dbo.sysobjects&nbsp;where&nbsp;name&nbsp;=&nbsp;'TableName'&nbsp;and&nbsp;&nbsp;type&nbsp;=&nbsp;'u')<br>如果这个表实临时表的话，那就变了：<br>create&nbsp;table&nbsp;#abc<br>(id&nbsp;int<br>)&nbsp;<br>select&nbsp;*&nbsp;from&nbsp;tempdb.dbo.sysobjects&nbsp;<br>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;where&nbsp;id&nbsp;=&nbsp;object_id('tempdb.dbo.#abc')

如果新建的数据库是名是syjxc,表名是show1,域名是n_code,n_code&nbsp;varchar&nbsp;3,不用except能给出具体的例子把

select&nbsp;*&nbsp;from&nbsp;dbo.sysobjects&nbsp;where&nbsp;id&nbsp;=&nbsp;object_id(N'[dbo].[MyTable]')&nbsp;and&nbsp;OBJECTPROPERTY(id,&nbsp;N'IsUserTable')&nbsp;=&nbsp;1中,sysobjects是什么,id&nbsp;=&nbsp;object_id是什么,<br>OBJECTPROPERTY(id,&nbsp;N'IsUserTable')是什么

.........<br>sysobjects是系统表，object_id，OBJECTPROPERTY都是sql&nbsp;server的系统函数啊，<br>就像select&nbsp;count(*)整的count一样

如果表已经存在,我想增加字段,请给出代码,这种情况最常见,还有数据库升级一般是怎么做的

alter&nbsp;table&nbsp;MyTable&nbsp;add&nbsp;&quot;Name&quot;&nbsp;varchar&nbsp;(30)&nbsp;NULL<br>这不就是增加字段吗。

delphi中的相应操作就是在adoquery中执行上述增加表或字段的sql代码

alter&nbsp;table&nbsp;MyTable&nbsp;add&nbsp;&quot;Name&quot;&nbsp;varchar&nbsp;(30)&nbsp;NULL<br>这不就是增加字段吗。如果该字段已经存在的话，会出错，<br>我想先判断是否有这个字段，没有就增加，请给出代码

老大，有问题能不能一气儿说完啊？<br><br>/*&nbsp;检查用户表&nbsp;MyTable&nbsp;是否存在&nbsp;*/<br>if&nbsp;exists&nbsp;(select&nbsp;*&nbsp;from&nbsp;dbo.sysobjects&nbsp;where&nbsp;id&nbsp;=&nbsp;object_id(N'MyTable')<br>&nbsp;&nbsp;and&nbsp;OBJECTPROPERTY(id,&nbsp;N'IsUserTable')&nbsp;=&nbsp;1)<br>begin<br>&nbsp;&nbsp;/*&nbsp;检查MyTable表中是否已有&quot;Name&quot;字段&nbsp;*/<br>&nbsp;&nbsp;IF&nbsp;Not&nbsp;Exists(<br>&nbsp;&nbsp;&nbsp;&nbsp;SELECT&nbsp;*&nbsp;FROM&nbsp;syscolumns&nbsp;WHERE&nbsp;(id&nbsp;=&nbsp;OBJECT_ID(N'MyTable'))<br>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;AND&nbsp;(OBJECTPROPERTY(id,&nbsp;N'IsUserTable')&nbsp;=&nbsp;1)&nbsp;AND&nbsp;(name&nbsp;=&nbsp;'Name')&nbsp<br>&nbsp;&nbsp;BEGIN<br>&nbsp;&nbsp;&nbsp;&nbsp;/*&nbsp;为MyTable表增加&quot;Name&quot;字段——类型为varchar，长度为30，可为空&nbsp;*/<br>&nbsp;&nbsp;&nbsp;&nbsp;alter&nbsp;table&nbsp;MyTable&nbsp;add&nbsp;&quot;Name&quot;&nbsp;[varchar]&nbsp;(30)&nbsp;NULL<br>&nbsp;&nbsp;END<br>end<br>else<br>begin<br>&nbsp;&nbsp;/*&nbsp;创建具有ID以及Name字段的MyTable表&nbsp;*/<br>&nbsp;&nbsp;CREATE&nbsp;TABLE&nbsp;[dbo].[MyTable]&nbsp;(<br>&nbsp;&nbsp;&nbsp;&nbsp;[ID]&nbsp;[int]&nbsp;NOT&nbsp;NULL,<br>&nbsp;&nbsp;&nbsp;&nbsp;[Name]&nbsp;[varchar]&nbsp;(30)&nbsp;NULL<br>&nbsp;&nbsp<br>end