Deleting rows from a table using a loop

Question

Why does my Do Until loop try to run raw.Delete even though raw.EOF is true? If I have an empty table, this crashes. Why?

Dim raw As Recordset
Set raw = db.OpenRecordset("tblSampleRaw")

If raw.RecordCount > 0 Then
    raw.MoveFirst

    Do Until raw.EOF
        raw.MoveFirst
        raw.Delete
    Loop
End If

Answer 1

I'm not a VB programmer, but it looks like 'raw' is going to keep dropping through the loop even after it executes 'MoveFirst'.

Answer 2

How about Dim raw AS DAO.Recordset?

Answer 3

You are doing a Row-By-Agonizing-Row or RBAR (reebar) operation. The larger the table, the more time this is going to take.

Most databases can work more efficiently than RBARs. I suggest you think in terms of SETS rather than rows.

I think you should replace that entire block of code with this:

DoCmd.RunSQL "DELETE * FROM tblSampleRaw"

for purposes of the answer

Dim raw As Recordset
Set raw = db.OpenRecordset("tblSampleRaw")

If raw.RecordCount > 0 Then
    raw.MoveFirst

    WHILE NOT raw.EOF or raw.BOF
        raw.MoveFirst
        raw.Delete
    Loop
End If

Answer 4

I'm not sure, or a VBA expert, but how come you are constantly doing a MoveFirst? Your never moving forward in the recordset. Try

Do Until raw.EOF
        raw.Delete
        raw.MoveNext
 Loop