如何从函数返回记录集

Question

我在Excel VBA中构建数据访问层，并且无法返回记录集。我的类中的Execute（）函数肯定是从数据库中检索一行，但似乎没有返回任何东西。

以下函数包含在名为DataAccessLayer的类中。该类包含用于打开和关闭连接的函数Connect和Disconnect。

Public Function Execute(ByVal sqlQuery As String) As ADODB.recordset 
    Dim rs As ADODB.recordset 
    Set rs = New ADODB.recordset 
    Dim recordsAffected As Long 

    ' Make sure we're connected to the database. 
    If Connect Then 
     Set command = New ADODB.command 

     With command 
      .ActiveConnection = connection 
      .CommandText = sqlQuery 
      .CommandType = adCmdText 
     End With 

     'Set rs = command.Execute(recordsAffected) 
     'Set Execute = command.Execute(recordsAffected) 
     rs.Open command.Execute(recordsAffected) 
     rs.ActiveConnection = Nothing 
     Set Execute = rs 
     Set command = Nothing 
     Call Disconnect 
    End If 
End Function 

这是我在电子表格A1单元格中用于测试的公共函数。

Public Function Scott_Test() 
    Dim Database As New DataAccessLayer 
    'Dim rs As ADODB.recordset 
    'Set rs = CreateObject("ADODB.Recordset") 
    Set rs = New ADODB.recordset 

    Set rs = Database.Execute("SELECT item_desc_1 FROM imitmidx_sql WHERE item_no = '11001'") 
    'rs.Open Database.Execute("SELECT item_desc_1 FROM imitmidx_sql WHERE item_no = '11001'") 
    'rs.Open 

    ' This never displays. 
    MsgBox rs.EOF 

    If Not rs.EOF Then 
     ' This is displaying #VALUE! in cell A1. 
     Scott_Test = rs!item_desc_1 
     rs.Close 
    End If 

    rs.ActiveConnection = Nothing 
    Set rs = Nothing 
End Function 

我在做什么错？

Answer 1

的问题是与设置的ActiveConnection =什么。下面的代码工作：

Public Function Execute(ByVal sqlQuery As String) As ADODB.recordset 
    Dim rs As ADODB.recordset 
    Set rs = New ADODB.recordset 
    Dim recordsAffected As Long 

    ' Make sure we are connected to the database. 
    If Connect Then 
     Set command = New ADODB.command 

     With command 
      .ActiveConnection = connection 
      .CommandText = sqlQuery 
      .CommandType = adCmdText 
     End With 

     rs.Open command.Execute(recordsAffected) 

     Set Execute = rs 
     Set command = Nothing 
     Call Disconnect 
    End If 
End Function

Answer 2

Set Execute = recordset 

创建一个指向记录集的指针，在退出函数时关闭它。
这就是为什么它不能包含任何东西。

我也对您的变量名称进行了重新定义，它们与possibe保留字（记录集）相同。我通常使用rs或rsIn或rsWhateverYouWant ...

Answer 3

正如Patrick所说，记录集是一个指针。 调用者'Scott_Test'应调用recordset.Close。

Execute方法不能打电话recordset.Close，但是我相信这是确定离开recordset.ActiveConnection =无