Oracle Learning Library
...free online learning content. The content ranges from videos, tutorials, articles, demos, step-by-step instructions to accomplish a specific task to in-depth, self-paced interactive learning modules.
PL/SQL Email Client API
...sending emails is no problem and frequently done from Oracle database installations. But there is no package which is able to retrieve messages from a mailbox on a server. The here provided package MAIL_CLIENT closes this gap.
Oracle Scratchpad - NVL2()
... it’s a nice little option if you want to create a function-based index that indexes only those rows where a column is null.
Execute current worksheet file via SQL*Plus
It’s a great feature to execute SQL scripts in a controlled and fresh environment without the hassle of opening SQL*Plus, connecting to the database and executing your script manually.
Sad but true, SQL Developer doesn’t offer such a feature out of the box.