There are a number of things that can be extended in SQL developer and a number of ways to do it.
Some of the examples that you see within this repository can be executed in the free web-based tool: LiveSQL.oracle.com. LiveSQL is also an excellent resource for getting started with Oracle Database.
Pl/sql stands for Procedural Language/Structured Query Language. It is a programming language that extends the capabilities of SQL, the standard language for querying and manipulating data in ...