The listening type is a music-data type whose values are stored in the music_data table, discriminator value listening.

The listening element has a list of subelements (sync or other-listening) whose records are stored in the listening table and joined to the parent listening record in the music_data table on foreign key listening_id.

The listening table is a single-inheritance table whose listening_type discriminator values are:

• sync
• other listening

The other-listening type can also be found as a type of listen object. In these cases, there's a listen record, discrminator value other listen and joined to the listening table on foreign key other_listening_id. The other-listening values are stored in the listening table.