Oracle Stored function Vs Join in queries

Question

I want to retrieve data from two tables.
The two tables are related with a foreign key reference. I've the following two ways to do this. But don't know which one is the better way.

1. A stored function call from the query
2. Using a join clause

Which will be the better way? I'm using the technologies: Oracle12c, Java, IBatis. So what is the best way to achieve this?

Answer 1

As join keeps everything at SQL level, it should be a better choice.

Using a function - which is PL/SQL - causes context switching (from SQL to PL/SQL and back to SQL to PL/SQL...) which will take resources.

You won't notice anything if there's a small data set, but - as number of rows involved gets higher, execution time will probably suffer in the second option.

If you'll be testing it, run every option several times because of possible caching.