We would like to monitor a Firebird database but do not know if theAPM SQL User Experience monitor will work and if so how.
The Orion APM "SQL Server User Experience" monitor is only for the Microsoft SQL Server.
For something like Firebird DB, you have to use the "ODBC User Experience" monitor type. I Google searched for some information you will need to use the Firebird ODBC driver:
Firebird ODBC driver (install this on Orion APM server): http://www.firebirdsql.org/index.php?op=files&id=odbc
Connection string for Firebird ODBC (use this in the ODBC User Experience monitor): http://connectionstrings.com/firebird
SolarWinds Documentation for ODBC UE monitor: http://www.solarwinds.com/netperfmon/SolarWinds/wwhelp/wwhimpl/common/html/wwhelp.htm#context=SolarWinds&file=OrionAPMPHComponentTypesOdbcQA.htm