Avoid DEFAULT KEY

" anti-pattern
DATA itab TYPE STANDARD TABLE OF row_type WITH DEFAULT KEY.

Default keys are often only added to get the newer functional statements working. The keys themselves in fact are usually superfluous and waste resources for nothing. They can even lead to obscure mistakes because they ignore numeric data types. The SORT and DELETE ADJACENT statements without explicit field list will resort to the primary key of the internal table, which in case of usage of DEFAULT KEY can lead to very unexpected results when having e.g. numeric fields as component of the key, in particular in combination with READ TABLE ... BINARY etc.

Either specify the key components explicitly

DATA itab2 TYPE STANDARD TABLE OF row_type WITH NON-UNIQUE KEY comp1 comp2.

or resort to EMPTY KEY if you don’t need a key at all.

DATA itab1 TYPE STANDARD TABLE OF row_type WITH EMPTY KEY.

Following Horst Keller’s blog on Internal Tables with Empty Key

Caution: SORT on internal tables with EMPTY KEY (without explicit sort fields) will not sort at all, but syntax warnings are issued in case the key’s emptiness can be determined statically.