Release 10.1A: OpenEdge Development:
Progress 4GL Handbook

ADD-BUFFER method

This method takes a single buffer handle as an argument and adds it to the list of buffers for the query. In this way, you can have a programming loop that adds a sequence of buffers to a query one at a time, when that is appropriate and when your query needs to join two or more buffers. It returns true if the operation succeeded and false otherwise.

For example, you can use the ADD-BUFFER method to add a third buffer to the query that already has the Order and Customer buffers assigned to it:

DEFINE VARIABLE hQuery AS HANDLE      NO-UNDO. CREATE QUERY hQuery. hQuery:SET-BUFFERS(BUFFER Order:HANDLE, BUFFER Customer:HANDLE). hQuery:ADD-BUFFER(BUFFER SalesRep:HANDLE).

Like the SET-BUFFERS method, ADD-BUFFER is supported only for dynamic queries for the same reason that you cannot modify the buffer list of a static query.