VB6 ADODB.Recordset RecordCount属性始终返回-1

Question

我试图获得一些旧的VB6代码与SQL Server Compact一起使用.

我可以连接,打开数据库,一切似乎都很好.我可以运行插入选择命令.

但是,ADODB.Recordset RecordCount属性始终返回-1,即使我可以访问Fields并查看数据.更改CursorLocation = adUseClient会在执行SQL(多步操作生成错误)时导致问题.

Option Explicit
    Private Const mSqlProvider          As String = "Provider=Microsoft.SQLSERVER.CE.OLEDB.3.5;"
    Private Const mSqlHost              As String = "Data Source=C:\Database.sdf;"
    Private mCmd                        As ADODB.Command   ' For executing SQL
    Private mDbConnection               As ADODB.Connection


Private Sub Command1_Click()


   Dim rs As ADODB.Recordset

    Set rs = New ADODB.Recordset


    Dim DbConnectionString As String

    DbConnectionString = mSqlProvider & _
                            mSqlHost


    Set mDbConnection = New ADODB.Connection
    mDbConnection.CursorLocation = adUseServer

    Call mDbConnection.Open(DbConnectionString)

    If mDbConnection.State = adStateOpen Then
        Debug.Print (" Database is open")
        ' Initialise the command object
        Set mCmd = New ADODB.Command
        mCmd.ActiveConnection = mDbConnection

        mCmd.CommandText = "select * from myTestTable"
        mCmd.CommandType = adCmdText

        Set rs = mCmd.Execute

        Debug.Print rs.RecordCount  ' Always returns -1  !!
        Debug.Print rs.Fields(0)   ' returns correct data for first row, first col
        Debug.Print rs.Fields(1)   ' returns correct data for first row, 2nd col
        Debug.Print rs.Fields(2)   ' returns correct data for first row, 3rd col

    End If

End Sub

任何建议都会被感激地接受.

Answer 1

实际上,CursorLocation在这种情况下起着重要作用.使用rs.CursorLocation = adUseClient设置光标位置和尝试.

    Set rs = New ADODB.Recordset
    rs.CursorLocation = adUseClient
    Dim DbConnectionString As String

    DbConnectionString = mSqlProvider & _
                            mSqlHost


    Set mDbConnection = New ADODB.Connection
    mDbConnection.CursorLocation = adUseServer

    Call mDbConnection.Open(DbConnectionString)

    If mDbConnection.State = adStateOpen Then
        Debug.Print (" Database is open")
        ' Initialise the command object
        Set mCmd = New ADODB.Command
        mCmd.ActiveConnection = mDbConnection

        mCmd.CommandText = "select * from myTestTable"
        mCmd.CommandType = adCmdText

        Set rs = mCmd.Execute

        Debug.Print rs.RecordCount  ' This should now return the right value.
        Debug.Print rs.Fields(0)   ' returns correct data for first row, first col
        Debug.Print rs.Fields(1)   ' returns correct data for first row, 2nd col
        Debug.Print rs.Fields(2)   ' returns correct data for first row, 3rd col

    End If

End Sub

Answer 2

这是由用于访问数据的游标类型造成的，本文将介绍该问题和可能的修复方法。

http://www.devx.com/tips/Tip/14143

编辑

我很抱歉没有更加关注您正在处理 Compact 的事实。对于 Compact，情况与我引用的情况类似，因为它默认使用仅向前游标（不支持行计数），但还有两种其他游标类型可用，如下面的链接中所述。

http://support.microsoft.com/kb/272067