System Exceptions

An exception is a message that is generated when an error occurs.

All exceptions handled by Firebird have predefined numeric values for context variables (symbols) and text messages associated with them.Error messages are output in English by default.Localized Firebird builds are available, where error messages are translated into other languages.

Complete listings of the system exceptions can be found in [fblangref50-appx02-errorcodes]:

Custom exceptions can be declared in the database as persistent objects and called in PSQL code to signal specific errors;for example, to enforce certain business rules.A custom exception consists of an identifier, and a default message of 1021 bytes.For details, see CREATE EXCEPTION.