_Subsystem_db_link.Sf_ID
| Description | Pointer to '_Assembly_subsystem.Sf_ID' | 
| Details: | |
| This tag contains a saveframe ID unique within BMRB database. It exists only in the database and is not exported to NMR-STAR files. Saveframe IDs are automatically generated and are not expected to be stable between different versions of the BMRB database.  | |
| Parent saveframe | assembly_subsystems | 
| Data type | int | 
| DB table | Subsystem_db_link | 
| DB column | Sf_ID | 
| DB type | INTEGER | 
| NULL allowed | no (mandatory) |