Firebird is a fully featured and powerful RDBMS and is derived from Borland InterBase 6.0 source code, which has more than 20 years of handling databases from just a few KB to many Gigabytes with good performance and almost free of maintenance!
It is open source and has no dual license. Below is a list of some of the Firebird’s major features:
Firebird has full SQL 92 Entry Level 1 Support and implements most of the SQL-99 standard, plus some very useful additions.
Full support of Stored Procedures and Triggers
Full ACID compliant transactions
Multi Generational Architecture
Very small footprint
Fully featured internal language for Stored Procedures and Triggers (PSQL)
Support for External Functions (UDFs)
Little or no need for specialized DBAs
Almost no configuration needed - just install and start using!
Big community and lots of places where you can get free and good support
Optional single file embedded version - great to create CDROM catalogs, single user or evaluation versions of applications
Dozens of third party tools, including GUI administrative tools, replication tools, etc.
Careful writes - fast recovery, no need for transaction logs!
Many ways to access your database: native/API, dbExpress drivers, ODBC, OLEDB, .Net provider, JDBC native type 4 driver, Python module, PHP, Perl, etc.
Native support for all major operating systems, including Windows, Linux, Solaris, MacOS.
Firebird is financially supported by Firebird Foundation which get his founds from company donations and paid membership subscriptions.