While ISRCs are the preferred identifier for identifying sound recording when communicating about releases and contained resources, they are not able to be used as primary keys in anyone's database.There are at least three reasons for this:

Because of these reasons it is essential that companies use an internally generated code as the primary key for each of the objects they handle. And may be necessary to keep a copy of a SoundRecodring descriptor for each Release.

The principle same applies for ISWCs for musical works, GRIDs for releases and all other creations.