ABAP & ABAP OO

Where I use it

Everything starts here. Around 60 custom reports and functions across MM, SD, FI, FM, WM, PP and QM, on five implementation projects and one maintenance engagement.

How I write ABAP

Objects, not includes. Classic ABAP reports grow into thousand-line includes that only their author can navigate. A local class per responsibility — one for selection, one for the data read, one for the business rules, one for output — stays readable and, more importantly, stays testable.

Separate reading from deciding from displaying. The single most useful structural rule I know. When the database read is isolated in its own method, you can profile it. When the business rule is isolated, you can unit-test it without a database at all.

Exceptions over return codes. RAISE EXCEPTION TYPE with a proper exception class carries context that sy-subrc = 4 never will.

Things I had to learn the hard way

SELECT inside a LOOP is the default performance bug. It passes every test on a development system with a hundred rows and collapses on production volumes. Read the set once, sort it, and use a hashed or sorted table to look up inside the loop.

FOR ALL ENTRIES needs a guard. If the driver table is empty, the statement reads everything. Check it first, every time.

Field symbols instead of work-area copies when looping over large internal tables — ASSIGNING <fs> avoids copying each row.

Do not swallow errors. A TRY / CATCH with an empty CATCH block is a bug you will find at 2 a.m. six months later.

What I would tell someone starting

Read standard SAP code. Not to copy it — some of it is thirty years old — but because you will discover that most requirements for a custom program are actually a standard transaction that was never configured. The best custom object is often the one you talk the client out of.

To expand: worked examples — an ALV report structured as classes, and the internal-table patterns that matter at volume.