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Deleting Records Using the Delete Method

  • Άρθρο

Using the Delete method marks the current record or a group of records in a Recordset object for deletion. If the Recordset object does not allow record deletion, an error occurs. If you are in immediate update mode, deletions occur in the database immediately. If a record cannot be successfully deleted (due to database integrity violations, for example), the record will remain in edit mode after the call to Update. This means that you must cancel the update using CancelUpdate before moving off the current record (for example, using Close, Move, or NextRecordset).

If you are in batch update mode, the records are marked for deletion from the cache and the actual deletion happens when you call the UpdateBatch method. (To view the deleted records, set the Filter property to adFilterAffectedRecords after Delete is called.)

Attempting to retrieve field values from the deleted record generates an error. After deleting the current record, the deleted record remains current until you move to a different record. Once you move away from the deleted record, it is no longer accessible.

If you nest deletions in a transaction, you can recover deleted records by using the RollbackTrans method. If you are in batch update mode, you can cancel a pending deletion or group of pending deletions by using the CancelBatch method.

If the attempt to delete records fails because of a conflict with the underlying data (for example, a record has already been deleted by another user), the provider returns warnings to the Errors collection but does not halt program execution. A run-time error occurs only if there are conflicts on all the requested records.

If the Unique Table dynamic property is set and the Recordset is the result of executing a JOIN operation on multiple tables, the Delete method will delete rows only from the table named in the Unique Table property.

The Delete method takes an optional argument that allows you to specify which records are affected by the Delete operation. The only valid values for this argument are either of the following ADO AffectEnum enumerated constants:

  • adAffectCurrent Affects only the current record.

  • adAffectGroup Affects only records that satisfy the current Filter property setting. The Filter property must be set to a FilterGroupEnum value or an array of Bookmarks to use this option.

The following code shows an example of specifying adAffectGroup when calling the Delete method. This example adds some records to the sample Recordset and updates the database. Then it filters the Recordset using the adFilterAffectedRecords filter enumerated constant, which leaves only the newly added records visible in the Recordset. Finally, it calls the Delete method and specifies that all of the records that satisfy the current Filter property setting (the new records) should be deleted.

'BeginDeleteGroup  
    'add some bogus records  
    With objRs  
        For i = 0 To 8  
            .AddNew  
            .Fields("CompanyName") = "Shipper Number " & i + 1  
            .Fields("Phone") = "(425) 555-000" & (i + 1)  
            .Update  
        Next i  
  
        ' update  
        .UpdateBatch  
  
        'filter on newly added records  
        .Filter = adFilterAffectedRecords  
        Debug.Print "Deleting the " & .RecordCount & _  
                    " records you just added."  
  
        'delete the newly added bogus records  
        .Delete adAffectGroup  
        .Filter = adFilterNone  
        Debug.Print .RecordCount & " records remain."  
    End With  
'EndDeleteGroup