ADO更改一条记录的值为何出错？

[tercel001]

有一数据库 Test.mdb 中，有一表A,有两个字段
a和b，其数据类型相同
dim oCnn as new adodb.connection
dim cmd as new adodb.command
dim rt as adodb.recordset
dim strLink as String

strLink = "Provider=Microsoft.Jet.OLEDB.4.0;Data Source=C:\Test.mdb;Mode=ReadWrite|Share Deny None;Persist Security Info=False"

oCnn.CursorLocation = adUseClient
oCnn.open strLink

cmd.ActiveConnection = oCnn
cmd.CommandType = adCmdText
cmd.CommandText = "select a,b from A"
Set rt = cmd.Execute

while(not rt.eof )
rt.fields("a").value=rt.fields("b").value
rt.movenext
wend

到这个地方，报错说

当前记录集不支持更新。这可能是提供程序的限制，也可能是选定锁定类型的限制。

请问这个问题该如何解决？
谢谢了

[Andy__Huang]

while(not rt.eof )
rt.fields("a").value=rt.fields("b").value
rt.update
rt.movenext
wend

[饮水需思源]

ocnn.execute " update A set a=b "

[mikimon]

dim cn as new adodb.connection

cn.open connectstring
cn.execute("update A set a=newvalue,b=newvalue where a=? or b=?")

[haohaohappy]

dim cn As New ADODB.Connection
dim Rs as new adodb.recordset
Cn.ConnectionString = "Provider=Microsoft.Jet.OLEDB.4.0;Data Source=c:\test.mdb;Persist Security Info=False"
Cn.CursorLocation = adUseClient
Cn.Open

Rs.Open "select a,b from A", CnDoingWeld, adOpenDynamic, adLockBatchOptimistic
rs.movefirst
do while rs.eof<>true
rs.fields("a").value=rs.fields("b")
rs.movenext
loop

[zhujiechang]

Set rt = cmd.Execute
使用command命令集的情况下,默认记录集为只读.改参数

[frankwong]

'如果楼主一定要使用command,那么
cmd.ActiveConnection = oCnn
cmd.CommandType = adCmdtable
cmd.CommandText = "A"
Set rt = cmd.Execute

while(not rt.eof )
rt.fields("a").value=rt.fields("b").value
rt.fields("a").update
rt.movenext
wend