Microsoft KB Archive/208184

= ACC2000: Action Query Commits Changes to Data When Cancelled =

Article ID: 208184

Article Last Modified on 6/30/2004

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APPLIES TO


 * Microsoft Access 2000 Standard Edition

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This article was previously published under Q208184





SYMPTOMS
Novice: Requires knowledge of the user interface on single-user computers.

When you run an action query and respond to the prompt to commit the changes by clicking No, the changes are committed anyway.



CAUSE
The action query's UseTransaction property is set to No.



RESOLUTION
Set the UseTransaction property to Yes before running the action query.



MORE INFORMATION
The UseTransaction property specifies whether an action query runs as a single transaction. When the UseTransaction property is set to Yes, the query results are stored in a cache or temporary database and are not written into the current database until you confirm that you want to commit the changes. When the UseTransaction property is set to No, the results are written immediately to the current database; the query runs much faster because it is not wrapped in a single transaction. However, you cannot cancel the changes that the query has made, even if you click No when prompted to commit the changes.

If you create a query in the Microsoft Access user interface by opening a new query in Design view, the default value of the UseTransaction property is Yes. However, when you use Data Access Objects (DAO) to create a QueryDef in Visual Basic for Applications code, the default value of the UseTransaction property is No.

In the following example, the procedure, CreateTransQuery, creates an action query whose UseTransaction property is set to Yes:

NOTE: The sample code in this article uses Microsoft Data Access Objects. For this code to run properly, you must reference the Microsoft DAO 3.6 Object Library. To do so, click References on the Tools menu in the Visual Basic Editor, and make sure that the Microsoft DAO 3.6 Object Library check box is selected.

 Open the sample database Northwind.mdb.  Create a module and type the following line in the Declarations section if it is not already there: Option Explicit   Type the following procedure: Function CreateTransQuery

Dim db As DAO.Database Dim qd As DAO.QueryDef Dim prpUseTrans As Property Dim strSQLString As String

strSQLString = "UPDATE Categories SET Categories.CategoryName" strSQLString = strSQLString & " = 'Drinks' WHERE" strSQLString = strSQLString & " Categories.CategoryID = 1;" Set db = CurrentDb Set qd = db.CreateQueryDef("qryUseTransTest", strSQLString) Set prpUseTrans = qd.CreateProperty("UseTransaction", dbBoolean, True) qd.Properties.Append prpUseTrans

End Function 

Steps to Reproduce Behavior
 Open the sample database Northwind.mdb.</li>  Open the Customers table and view the first record. Note that it contains the following data: <pre class="fixed_text">     CustomerID:    CompanyName: ---         ALFKI          Alfred's Futterkiste </li>  Close the table. Then, create a new update query based on the Customers table, and add the following fields: <pre class="fixed_text">     Query: qryUpdateCustomers -     Type: Update Query

Field: CustomerID Criteria: "ALFKI" Field: CompanyName Update To: "Alfred's Co." </li> Click anywhere in the upper portion of the QBE grid. Then, on the View menu, click Properties to view the query's property box.</li> Set the UseTransaction property to No.</li>  On the Query menu, click Run. Note that you receive the message: <pre class="fixed_text">  You are about to update 1 row(s).

Once you click Yes, you can't use the Undo command to reverse the changes. Are you sure you want to update these records? </li> Click No, indicating that you do not want to commit the changes.</li> Close the query and save it as qryUpdateCustomers.</li> Open the Customers table, and view the first record. Note that now the data in the CompanyName field contains "Alfred's Co."</li></ol>

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