Apex: Caveat PK column name length
It is highly encouraged in Apex to use system generated, single primary key columns whenever possible.
When choosing multi-column, composed primary keys, you quickly get in trouble when dealing with the standard MRU Processes. This is limited to handling tables with at most a 2 column primary key.
So, it is a good practice to work with auto-generated, sequence-based PK’s, on 1 column.
There is one caveat that you should be aware of.
Within Oracle, the maximum length of a column name is 30 characters.
However, when you plan to build tabular forms on your tables, the length of the primary key column name may not exceed 22 characters.

July 13, 2007 at 4:16 am |
Hi JanThat’s a very useful tip.So I don’t lose it, I’ve linked to it in my blog.