vb登陆界面连接ACCESS数据库

例：数据库名：user；表名:account；字段u_id,u_name,u_pass；界面：txtuname[用户名文本框],txtpass[用户口令文本框]；程序主界面frmmain.frm。

'------------验证登录代码------------
dim conn as new adodb.connection
dim rs as new adodb.recordset
dim sql as string
dim connstr as string
connstr="provider=microsoft.jet.oledb.4.0;data source=user.mdb"
sql="select * from account where u_name='" & txtuname & "'"
conn.open(connstr)
rs.open sql,conn,1,1
if rs.recordcount=0 then
msgbox "用户不存在"
rs.close
conn.close
exit sub
end if
if txtpass<>rs("u_pass") then
msgbox "用户口令错误"
rs.close
conn.close
else
rs.close
conn.close
frmmain.show
unload me
end if
'----------------添加新用户------------------------
dim sql as string
sql="select * from account"
rs.open sql,conn,3,3
with rs