The main database, which we use at work - it's Oracle. We have started to work with the Oracle DBMS 7.3.4. It was in 1998. During this time, Oracle has reached version 12, and we have gained extensive experience in the development of systems based on it.
Now, when a free version of the Oracle DBMS was introduced, it become useful even in small projects. Limitations of this version are 11 Gb database size, 1Gb RAM and 1 processor. To check startups and process data in small companies of up to 200-300 people it is completely enough.
We also use Oracle APEX as a main framework to build user interfaces. It is quite convenient for developing Web based interfaces. In combination with the jQuery library it allows you to quickly create powerful user interfaces for multi-user operations.
On the base of the Oracle DBMS we have built a standard platform for rapid software development.
You can read more about its features and additional options.
Oracle Express Edition is suitable for most standard tasks
it is possible to quickly upgrade to a more powerful version without loss of performance
the most known database which was proved by time