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Home -> Community -> Usenet -> c.d.o.server -> Re: ODBC error trapping in MS Access
Hi everybody :-)
i found a working solution for trapping specific ODBC errors at http://support.microsoft.com/support/kb/articles/Q185/3/84.ASP?LN=DE&SD=SO&F R=0.
In case the URL will not be valid any more somewhen in the future, here's a copy:
ACC: Can't Trap Specific ODBC Errors in OnError Property of Form The information in this article applies to:
a.. Microsoft Access 2.0 b.. Microsoft Access for Windows 95, version 7.0 c.. Microsoft Access 97 d.. Microsoft Visual Basic for Applications
SYMPTOMS
Advanced: Requires expert coding, interoperability, and multiuser skills.
If you set the OnError property of a form to an event procedure, you cannot retrieve the description of an ODBC error in that procedure, and you cannot trap a specific ODBC error. When an ODBC error occurs, the only information that is passed to the OnError event procedure is the number of a generic error such as 3146, which corresponds to the error message:
ODBC--Call failed
CAUSE
ODBC error messages normally consist of two components. The first component
is error 3146, whose description is:
ODBC--Call failed
The server-specific error information is contained in the second component,
from which you can retrieve an error number and a description such as:
[Microsoft][ODBC SQL Server Driver][SQL Server] <Server-specific error message> (#<error number>) If you set the OnError property of a form to an event procedure, you can trap the number of the first component of the error, but you cannot trap the number of the second component. Unless you include the line
Response = acDataErrContinue
in the event procedure, the server-specific information in the second part
of the ODBC error appears on the screen after the code has finished running.
RESOLUTION
This resolution assumes that you are familiar with Visual Basic for
Applications and with creating Microsoft Access applications using the
programming tools provided with Microsoft Access. For more information about
Visual Basic for Applications, please refer to the "Building Applications
with Microsoft Access 97" manual.
You can create a Visual Basic for Applications procedure that uses Data Access Objects (DAO) to update a RecordsetClone based on the form and trap any error message that you receive.
DAO contains an Errors collection that you can use to trap the serverspecific information in the second part of the ODBC error. When an ODBC error occurs, the first component is stored in the first element of the Errors collection, and the second component is stored in the second element.
Microsoft provides programming examples for illustration only, without warranty either expressed or implied, including, but not limited to, the implied warranties of merchantability and/or fitness for a particular purpose. This article assumes that you are familiar with the programming language being demonstrated and the tools used to create and debug procedures. Microsoft support professionals can help explain the functionality of a particular procedure, but they will not modify these examples to provide added functionality or construct procedures to meet your specific needs. If you have limited programming experience, you may want to contact a Microsoft Certified Partner or the Microsoft fee-based consulting line at (800) 936-5200. For more information about Microsoft Certified Partners, please see the following page on the World Wide Web:
http://www.microsoft.com/partner/referral/ For more information about the support options available from Microsoft, please see the following page on the World Wide Web: http://support.microsoft.com/directory/overview.asp This example uses the BeforeUpdate event instead of the Error event to trap specific ODBC errors. To create a function that traps specific ODBC errors when the BeforeUpdate event of a form occurs, follow these steps.
CAUTION: Following the steps in this example will modify the sample database
Northwind.mdb. You may want to back up the Northwind.mdb file and perform
these steps on a copy of the database.
1.. Open the sample database Northwind.mdb.
2.. Link to the table dbo.authors in the Pubs sample database in Microsoft SQL Server.
3.. Use the AutoForm: Columnar wizard to create a new form based on the Authors table.
4.. Save the form as frmAuthors.
5.. Create a new module, and type the following line in the Declarations section if it doesn't already exist:
Option Explicit
6.. Type or paste the following procedure into the module:
NOTE: In the following sample code, an underscore (_) at the end of a line is used as a line-continuation character. Remove the underscore from the end of the line when re-creating this code.
Public Function SaveRecODBC(SRO_form As Form) As Boolean
'***************************************************************
'Function: SaveREcODBC
'Purpose: Updates a form based on a linked ODBC table
' and traps any ODBC errors.
'
'Arguments: SRO_Form, which refers to the form.
'
'
'Returns: True if successful or False if an error occurs.
'***************************************************************
On Error GoTo SaveRecODBCErr
Dim fld As Field, ctl As Control, prp As Property
Dim errStored As Error, RecChanged As Boolean
' Check to see if the record has changed.
If SRO_form.Dirty Then
If SRO_form.NewRecord Then
SRO_form.RecordsetClone.AddNew
For Each ctl In SRO_form.Controls
' Check to see if it is the type of control
' that has a ControlSource.
If ctl.ControlType = acTextBox Or _
ctl.ControlType = acComboBox Or _
ctl.ControlType = acListBox Or _
ctl.ControlType = acCheckBox Then
' Verify that a value exists in the ControlSource.
If ctl.Properties("ControlSource") <> "" Then
' Loop through the fields collection in the
' RecordsetClone. If you find a field name
' that matches the ControlSource, update the
' field. If not, skip the field. This is
' necessary to account for calculated controls.
For Each fld In SRO_form.RecordsetClone.Fields
' Find the field and verify
' that it is not Null.
' If it is Null, don't add it.
If fld.Name = ctl.Properties("ControlSource") _
And Not IsNull(ctl) Then
fld.Value = ctl
' Exit the For loop
' if you have a match.
Exit For
End If
Next fld
End If ' End If ctl.Properties("ControlSource")
End If ' End If ctl.controltype
Next ctl
SRO_form.RecordsetClone.Update
Else
' This is not a new record.
' Set the bookmark to synchronize the record in the
' RecordsetClone with the record in the form.
SRO_form.RecordsetClone.Bookmark = SRO_form.Bookmark
SRO_form.RecordsetClone.Edit
For Each ctl In SRO_form.Controls
' Check to see if it is the type of control
' that has a ControlSource.
If ctl.ControlType = acTextBox Or _
ctl.ControlType = acComboBox Or _
ctl.ControlType = acListBox Or _
ctl.ControlType = acCheckBox Then
' Verify that a value exists in the
' ControlSource.
If ctl.Properties("ControlSource") <> "" Then
' Loop through the fields collection in the
' RecordsetClone. If you find a field name
' that matches the ControlSource, update the
' field. If not, skip the field. This is
' necessary to account for calcualted controls.
For Each fld In SRO_form.RecordsetClone.Fields
' Find the field and make sure that the
' value has changed. If it has not
' changed, do not perform the update.
If fld.Name = ctl.Properties("ControlSource") _
And fld.Value <> ctl And _
Not IsNull(fld.Value <> ctl) Then
fld.Value = ctl
' Exit the For loop if you have a match.
Exit For
End If
Next fld
End If ' End If ctl.Properties("ControlSource")
End If ' End If ctl.controltype
Next ctl
SRO_form.RecordsetClone.Update
End If ' End If SRO_form.NewRecord
End If ' End If SRO_form.Dirty
' If function has executed successfully to this point then
' set its value to True and exit.
SaveRecODBC = True
Exit_SaveRecODBCErr:
Exit Function
SaveRecODBCErr:
' The function failed because of an ODBC error.
' Below are a list of some of the known error numbers.
' If you are not receiving an error in this list,
' add that error to the Select Case statement.
For Each errStored In DBEngine.Errors
Select Case errStored.Number
Case 3146
' No action -- standard ODBC--Call failed error.
Case 2627
' Error caused by duplicate value in primary key.
MsgBox "You tried to enter a duplicate value " & _
"in the Primary Key."
Case 3621
' No action -- standard ODBC command aborted error.
Case 547
' Foreign key constraint error.
MsgBox "You violated a foreign key constraint."
Case Else
' An error not accounted for in the Select Case
' statement.
MsgBox errStored.Description & " " & errStored.Number
End Select
Next errStored
SaveRecODBC = False
Resume Exit_SaveRecODBCErr
End Function
Sub Form_BeforeUpdate (Cancel As Integer)
' If you can save the changes to the record,
' undo the changes on the form.
If SaveRecODBC(Me) Then
Me.Undo
' If this is a new record, go to the last record on
' the form.
If Me.NewRecord Then
' If you are using Microsoft Access 95,
' comment out the RunCommand line
' and remove the apostrophe from
' the following line.
' DoCmd.GoToRecord , , acLast
RunCommand acCmdRecordsGoToLast
End If
Else
' If you can't update the record, cancel
' the BeforeUpdate event.
Cancel = -1
End If
End Sub
9.. If no errors occur, save the form.
10.. Open the frmAuthors form and add a new record or edit a record. When you make a change to a record, it is saved when you move to a different record. If an ODBC error occurs, you see the custom message that is based on the server-specific error, and the generic "ODBC--call failed message" is trapped.
STATUS
Microsoft has confirmed this to be a problem in Microsoft Access versions
2.0 and later.
Happy coding!
Frank Received on Tue Sep 04 2001 - 06:09:40 CDT
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