vb 如果让所有窗体都连接上同一个数据库该怎么做啊？

在模块里面使用一个公共的函数，以下以Access数据库为例

Public Function ExeSQL(ByVal strSQL As String) As ADODB.Recordset
Dim Conn As ADODB.Connection
Dim rst As ADODB.Recordset
Set Conn = New ADODB.Connection
Conn.ConnectionString = "provider=Microsoft.Jet.OLEDB.4.0;Data Source =" & App.Path & "/data.mdb;Jet OLEDB"
Conn.Open
Dim stokens() As String
On Error GoTo err
stokens = Split(strSQL)
If InStr("INSER,DELETE,UPDATE", UCase(stokens(0))) Then
Conn.Execute (strSQL)
Else
Set rst = New ADODB.Recordset
rst.Open Trim(strSQL), Conn, 1, 3
Set ExeSQL = rst
End If
Erase stokens
strSQL = vbNullString
exe_exit:
Set rst = Nothing
Set Conn = Nothing
Exit Function
err:
MsgBox "发生错误，读取数据失败！"
Resume exe_exit
End Function

使用的时候直接调用就可以了：
Dim rs As ADODB.R