ADO Recordset data not showing on form - sql

Question

I've got a frustrating issue on MS Access 2010 that I would at this stage qualify as a bug. And after having tried all possible workarounds, I am out of ideas and rely on you.
Context
Huge Ms Access 2010 application with 25k lines of VBA and >50 forms. It has a client server architecture with a frontend compiled and an Access backend on the network. It makes connections to a twentish of different databases (Oracle/SQL Server/Sybase IQ).
The problem
Sometimes when I assign an ADODB recordset to a subform, its data isn't shown in bound fields. I've got #Name? everywhere
The data is there. I can debug.print it, I can see it in the Watches browser, I can read or manipulate it while looping on the recordset object with code. It just not appear in the subform.
It can work flawlessly during months, and suddenly one form will start having this issue without any apparent reason (it might happen even on forms that I have not changed). When it happens, it does for all users, so this is really something wrong in the frontend accdb/accde.
The issue is not related to a specific DBMS/Driver. It can happen with Oracle or Sybase data.
I have created my own class abstracting everything related to ADO connections and queries, and use the same technique everywhere. I've got several tenth of forms based on it and most of them works perfectly.
I have this issue in several parts of my application, and especially in a highly complicated form with lots of subforms and code.
On this Main form, a few subforms have the issue, while others don't. And they have the exact same parameters.
The Code
This is how I populate a form's recordset :
Set RST = Nothing
Set RST = New ADODB.Recordset
Set RST = Oracle_CON.QueryRS(SQL)
If Not RST Is Nothing Then
Set RST.ActiveConnection = Nothing
Set Form_the_form_name.Recordset = RST
End If
The code called with Oracle_CON.QueryRS(SQL) is
Public Function QueryRS(ByVal SQL As String, Optional strTitle As String) As ADODB.Recordset
Dim dbQuery As ADODB.Command
Dim Output As ADODB.Recordset
Dim dtTemp As Date
Dim strErrNumber As Long
Dim strErrDesc As String
Dim intSeconds As Long
Dim Param As Variant
If DBcon.state <> adStateOpen Then
Set QueryRS = Nothing
Else
DoCmd.Hourglass True
pLastRows = 0
pLastSQL = SQL
pLastError = ""
pLastSeconds = 0
Set dbQuery = New ADODB.Command
dbQuery.ActiveConnection = DBcon
dbQuery.CommandText = SQL
dbQuery.CommandTimeout = pTimeOut
Set Output = New ADODB.Recordset
LogIt SQL, strTitle
dtTemp = Now
On Error GoTo Query_Error
With Output
.LockType = adLockPessimistic
.CursorType = adUseClient
.CursorLocation = adUseClient
.Open dbQuery
End With
intSeconds = DateDiff("s", dtTemp, Now)
If Output.EOF Then
LogIt "-- " & Format(Now, "hh:nn:ss") & " | Executed in " & intSeconds & " second" & IIf(intSeconds = 1, "", "s") & " | Now rows returned."
Set QueryRS = Nothing
Else
Output.MoveLast
pLastRows = Output.RecordCount
LogIt "-- " & Format(Now, "hh:nn:ss") & " | Executed in " & intSeconds & " second" & IIf(intSeconds = 1, "", "s") & " | " & Output.RecordCount & " row" & IIf(Output.RecordCount = 1, "", "s") & " returned."
Output.MoveFirst
Set QueryRS = Output
End If
End If
Exit_Sub:
pLastSeconds = intSeconds
Set Output = Nothing
Set Parameter = Nothing
Set dbQuery = Nothing
DoCmd.Hourglass False
Exit Function
Query_Error:
intSeconds = DateDiff("s", dtTemp, Now)
strErrNumber = Err.Number
strErrDesc = Err.DESCRIPTION
pLastError = strErrDesc
MsgBox strErrDesc, vbCritical, "Error " & pDSN
LogIt strErrDesc, , "ERROR"
Set QueryRS = Nothing
Resume Exit_Sub
Resume
End Function
Things I tried so far
For the recordsets I tried every possible variation of
.LockType = adLockPessimistic
.CursorType = adUseClient
.CursorLocation = adUseClient
The subforms handling the recordsets have all a Snapshot recordsettype, problem remains if I try dynaset.
Dataentry, Addition, deletion, edits are all disabled. It's pure read-only.
I have a habit of disconnecting the recordsets using RST.ActiveConnection = Nothing so I can manipulate them afterwards, but this doesn't impact the problem either.
It can happens with very simple queries with only one field in the SELECT clause and only one field bound to it on a subform.
Reimporting all objects in a fresh accdb doesn't solve the problem either.
The solution proposed by random_answer_guy worked at first glance, which accreditate the bug hypothesis. Unfortunately my problems reappeared after some (totaly unrelated) changes in the main form. I am back with 4 or 5 subforms not showing data and adding/removing a Load event on all or part of them doesn't make any difference anymore
If you want more information about how weird is this issue, I advise you to read my comment on random_answer_guy's answer.
To conclude
What is extremely frustrating is that I can have 2 different forms with exactly the same properties and same fields, same SQL instruction over the same DB, same recordset management code: One is showing the data and the other doesn't !
When the problem happens, I have no other choice than erasing all objects manipulated and reimporting them from an older version or recreate them from scratch.
If this is not a bug, I am still looking for the proper word to qualify it.
Does anyone ever experienced the issue and has an explanation and/or a workaround to propose ?

Answer 1

I've had this same issue before and simply adding a blank Form_Load event solved the problem. No code needs to be with the Form_Load it just needs to be present.

Answer 2

So nobody could give at this stage a clear answer to the main question :
Why is this bug happens ?
In the meantime I have "elegantly" bypassed the issue by changing the method used for the subforms encountering the bug, from ADO to DAO.
I have created a new method in my ADO abstracting class, that actually use DAO to return a recordset (not logical, but hey...).
The code where I pass data to the form becomes :
Set RST = Nothing
Set RST = Oracle_CON.QueryDAORS(SQL)
If Not RST Is Nothing Then
Set Form_the_form_name.Recordset = RST
End If
And here's the method QueryDAORS called :
Public Function QueryDAORS(ByVal SQL As String, Optional strTitle As String) As DAO.Recordset
Dim RS As DAO.Recordset
Dim dtTemp As Date
Dim strErrNumber As Long
Dim strErrDesc As String
Dim intSeconds As Long
Dim Param As Variant
On Error GoTo Query_Error
dtTemp = Now
If DBcon.state <> adStateOpen Then
Set QueryDAORS = Nothing
Else
DoCmd.Hourglass True
Set pQDEF = CurrentDb.CreateQueryDef("")
pQDEF.Connect = pPassThroughString
pQDEF.ODBCTimeout = pTimeOut
pQDEF.SQL = SQL
pLastRows = 0
pLastSQL = SQL
pLastError = ""
pLastSeconds = 0
LogIt SQL, strTitle, , True
Set RS = pQDEF.OpenRecordset(dbOpenSnapshot)
intSeconds = DateDiff("s", dtTemp, Now)
If RS.EOF Then
LogIt "-- " & Format(Now, "hh:nn:ss") & " | Executed in " & intSeconds & " second" & IIf(intSeconds = 1, "", "s") & " | Now rows returned."
Set QueryDAORS = Nothing
Else
RS.MoveLast
pLastRows = RS.RecordCount
LogIt "-- " & Format(Now, "hh:nn:ss") & " | Executed in " & intSeconds & " second" & IIf(intSeconds = 1, "", "s") & " | " & RS.RecordCount & " row" & IIf(RS.RecordCount = 1, "", "s") & " returned."
RS.MoveFirst
Set QueryDAORS = RS
End If
End If
Exit_Sub:
pLastSeconds = intSeconds
Set RS = Nothing
DoCmd.Hourglass False
Exit Function
Query_Error:
intSeconds = DateDiff("s", dtTemp, Now)
strErrNumber = Err.Number
strErrDesc = Err.DESCRIPTION
pLastError = strErrDesc
MsgBox strErrDesc, vbCritical, "Error " & pDSN
LogIt strErrDesc, , "ERROR"
Set QueryDAORS = Nothing
Resume Exit_Sub
Resume
End Function
The property pPassThroughString is defined with another Method using the properties that I already had at my disposal in the class, because they were neccessary to open an ADO connection to the database :
Private Function pPassThroughString() As String
Select Case pRDBMS
Case "Oracle"
pPassThroughString = "ODBC;DSN=" & pDSN & ";UID=" & pUsername & ";Pwd=" & XorC(pXPassword, CYPHER_KEY)
Case "MS SQL"
pPassThroughString = "ODBC;DSN=" & pDSN & ";DATABASE=" & pDBname & ";Trusted_Connection=Yes"
Case "Sybase"
pPassThroughString = "ODBC;DSN=" & pDSN & ";"
Case Else
MsgBox "RDBMS empty ! ", vbExclamation
LogIt "RDBMS empty ! ", , "ERROR"
End Select
End Function
So the issue was solved rapidly by just changing the recordset assigned to the forms from ADODB.Recordset to DAO.recordset and adapting the method called from .OpenRS to .OpenDAORS.
The only con is that with DAO I can't use this anymore to disconnect the recordset:
Set RST.ActiveConnection = Nothing
Still, I would have prefered to get an explanation and fix :(