Release 10.1A: OpenEdge Development:
Progress 4GL Handbook

Using BUFFER-COPY and BUFFER-COMPARE

When copying fields from one record buffer to another, BUFFER-COPY does it more efficiently than ASSIGN. Use the EXCEPT option when some fields are not to be copied, and the ASSIGN option when some fields are renamed during the copy operation. Even doing a BUFFER-COPY of a table with 100 fields is faster than an ASSIGN statement that copies a half dozen of those fields.

In particular, the static BUFFER-COPY statement allows Progress to resolve the exact field list to copy and to identify the field mappings at compile time so that the operation can be made as fast as possible. Using the dynamic BUFFER-COPY method on a buffer handle requires Progress to evaluate the arguments during program execution, which of course is slower. As with all dynamic language, use the BUFFER-COPY method only when you truly don’t know the buffers or the fields to copy until run time.

All this applies equally well to the BUFFER-COMPARE statement or method which compares two buffers and returns a list of differences. BUFFER-COMPARE is much faster than using a series of explicit comparison statements on individual fields.