Use Cases and Deployment Scope
FirebirdSQL is a nearly zero maintenance, low footprint relational database system suited for all kinds of PC applications, since even an embedded version exists which doesn't require installation - just copy the files. It supports SQL and database sizes > 1 TB are no problem. It is fully Unicode compatible, drivers for various development environments are available either from the vendors of these environments or from 3rd parties and there exists a healthy open source community around it along with documentation.