User-Defined Functions (UDFs)
UDFs (User-Defined Functions) are functions that are not internal to the engine, but defined in separate modules.Firebird ships with two UDF libraries: ib_udf
(a widely used “InterBase library”) and fbudf
.You can add more libraries, e.g. by buying or downloading them, or by writing them yourself.UDFs can’t be used out of the box;they have to be “declared” to the database first.This also applies to the UDFs that come with Firebird itself.