File with a PDB extension contains structure of a database specific to a given application. There are several programs using this type of databases, however, each of them has also an option to store files in a different specific format which makes the files impossible to be loaded in different software.

Program utilising PDB databases are among others - Microsoft Visual Studio, Palm Pilot, Pegasus or Intuit Quicken. PDB database is usually installed along with software and a PDB database file from Palm Pilot (for instance,) will not be recognised in the Pegasus software.