How to pump the data from one database to another?
Many recommend IB Pump or IB Data Pump, but the problem is when you have complex relations between tables. In such cases, it is better to use tool like FBCopy which sorts the tables by dependencies (foreign keys, check constraints) into correct order:
Alternatively, you can disable the constraints during the import and turn them back on later.
If you wish to import data from non-Firebird data sources, then IB DataPump is probably the best free option available. It's even able to create the structure for Firebird database from scratch, so you can use it as a migration tool to migrate from other DBMS systems.
There are also some generic (not Firebird specific) data pump tools out there, which might be worth a try:
If you know about some other useful free tools for copying the data, please let us know.