Private Functions and ACCESSIBLE BY Packages in 12c

My recent post about PLS-00231 prompted an entirely reasonable question from Andrew :

“OK so the obvious question why [can’t you reference a private function in SQL] and doesn’t that defeat the objective of having it as a private function, and if so what about other ways of achieving the same goal ?”

I’ll be honest – that particular post was really just a note to self. I tend to write package members as public initially so that I can test them by calling them directly.
Once I’ve finished coding the package, I’ll then go through and make all of the helper package members private. My note was simply to remind myself that the PLS-00231 error when compiling a package usually means that I’ve referenced a function in a SQL statement and then made it private.

So, we know that a PL/SQL function can only be called in a SQL statement if it’s a schema level object or it’s definied in the package header because that’s the definition of a Public function in PL/SQL. Or at least it was…

In formulating an answer to Andrew’s question, it became apparent that the nature of Private functions have evolved a bit in 12c.

So, what I’m going to look at here is :

  • What are Private and Public package members in PL/SQL and why you might want to keep a package member private
  • How 12c language features change our definition of private and public in terms of PL/SQL objects
  • Hopefully provide some up-to-date answers for Andrew

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PL/SQL – A Programmer’s Introduction – or Welcome to the Dark Side

This week, the Open Source Karma has been cast-aside. We’re going proprietary in a big way. We’re going to the very heart of Oracle’s power, deep inside the RDBMS – yes – it’s PL/SQL.

This post is dedicated to ( and essentially co-written by) Simon. Yes, my long-time best mate, long-time Luton Town fan, long-time Teradata expert and long time everything really ( we’ll he’s not as young as he was).
After all these years, Simon has become a bit curious about this PL/SQL thing I’m always going on about and would like to know more.
It is this desire – and large amounts of beer – that has persuaded him to play the Igor to my mad scientist and have a wander through this very quick guide to the language at the heart of most Oracle applications. In fact we came up with several possible descriptions of Simon’s role in this post, but he had a “hunch” that this was the right one.
So for him, and any other programmers who want to get up and running with PL/SQL, but don’t need to be told what a variable is, what follows is – not so much a PL/SQL 101 – as a PL/SQL 23-and-a-bit. Continue reading