注册代码怎么写呀？？？？（新手急）

[henlai]

思路是这样的：
判断输入用户名是否和表（tuser）里面loginname字段一样
如果一样 则提示此用户明存在
否则 添加一条记录。


应该怎么写，请说详细些.

[angelheavens]

...
usernamevalue=request.form("usernamevalue"
...
set rs=conn.execute("select loginnamefield from registertable where loginnamefield='&usernamevalue&"'")
if not rs.eof or not rs.bof then
response.write "user is exist"
else
conn.execute("insert into...")
end if

[007james]

if rs.recordcount>0 then '表示存在
response.write "user is exist"
else '表示不存在
conn.execute("insert into...")
end if

[飞一龙]

sql=select * form tuser where loginname='" & request("表单名") & "'"
rs.conn sql , conn,3,2

if not rs.eof then
response.write"用户存在"
else
添加一条记录(去注册会员)
end if

[chense]

'连接数据库语句省略,连接对象为objConn
sUserName = Trim(Request("UserName")) '这里最好加个对输入字符进行判断的函数
strSql = "select * from tuser where loginname="&sUserName

Set objRs = Server.CreateObject("ADODB.RecordSet")
objRs.Open strSql,objConn,1,1

If Not objRs.Eof Then
Response.Write "用户名存在！"
Response.End
Else
objConn.Execute"insert into tuser(loginname) values('"& sUserName &"')"
End If

objRs.Close
Set objRs = Nothing
Set objConn = Nothing