Access Database Design and Programming, Second Edition

The Do Loop

The Do loop has several variations. To describe these variations, we use the notation:

               {While | Until}

to represent either the word While or the word Until, but not both. With this in mind, here are the possible syntaxes for the Do loop:

Do {While | Until} condition

   ' code block here

Loop

or:

Do

   ' code block here

Loop {While | Until} condition

Actually, there is a fifth possibility, because we can dispense with condition completely and write:

Do

   ' code block here

Loop

The Do loop is used quite often in DAO programming to iterate through a recordset. Here is a typical example that prints all values of a particular field in a recordset:

Sub DoExample()

Dim rs As Recordset
Set rs = CurrentDb.OpenRecordset("Objects")

rs.MoveFirst

Do While Not rs.EOF
   Debug.Print rs!Name
   rs.MoveNext
Loop

rs.Close

End Sub

We will discuss the EOF property as well as the MoveFirst and MoveNext methods when we discuss Recordset objects later in the book.

Just as the For loop has an Exit For statement for terminating the loop, a Do loop has an Exit Do statement for exiting the Do loop.