Table names are like aptrx (Accounts Payable Transactions) and
apmaster_all (curiously, this is the vendors table). It's an extremely
complex database, so I was wondering if there was any logic to the
convention or if it was simply being obfuscated intentionally or
Well-known abbreviations are usually preferable to spelling things out. When an abbreviation is well-known to some people, but not quite enough people, we stop calling it an abbreviation, and start calling it a code.
Abbreviations conserve space on platforms that have tight limits, although this is less important now than it was 30 years ago. (I seem to recall working on a system in the 1980s that limited you to either 6 or 8 characters for a table name.)
Abbreviations usually make table names and column names easier to read, as long as the abbreviating is done well. If I worked on code for AP all day, I'd rather read column names like "ap_trx.inv_num" than "accounts_payable_transactions.invoice_number". (I like underscores.) Typing long names isn't much of an issue with a good text editor.
In accounting systems, both "ap" and "trx" are well-known abbreviations. Others include "ar", "gl", and "gj", for accounts receivable, general ledger, and general journal.
In a well-designed system, if I found accounts payable transactions in a table named "aptrx", I'd hope to find accounts receivable transactions in artrx, general ledger transactions in gltrx, and so on. I find "apmaster_all" a little puzzling, but if I also found "armaster_all", I'd presume that the first held all the vendors (as opposed to active or inactive vendors), and that the second similarly held all the customers.
In other problem domains, you find other well-known abbreviations. In addressing, you'll find abbreviations like "addr" for address, "st" for street, "usps" for United States Postal Service, "ups" for United Parcel Service, "cty" for county, "zip" for Zone Improvement Code, and so on.
I wouldn't call this obfuscation. If accounts payable transactions were stored in a table named "cdrs21", I'd call that obfuscation. (Although I did once work for a company that named all their mainframe assembler modules that way. Character limits, not obfuscation.)
But useful databases grow, and you run into a problem when databases get big. As you add problem domains to your database, you run into situations where well-known abbreviations collide. If you deal with the media, then "ap" could also abbreviate "Associated Press", "alternative press", or "advance placement". When that happens, it's time to either abandon abbreviations, or switch to codes. The bigger the organization (and the bigger the database), the more frequently I find codes.