That's a good warning sign that the data isn't relational in the first place. An RDBMS would probably be a good fit for the analyzed data (which is likely to have explicit relations), though.
No it's not. There are plenty of tables that use composite keys that also contain foreign keys.
The use of ORMs like active record, many of which choke on natural keys, has turned a lot of devs into automatons for artificial key creation. Natural keys are often superior.
