What is the difference between a "Repository" and a "Database"?

The Metasafe Repository is a (DMBS) Database Management System. There are many types of DMBS with different core models: Oracles, SQLServer, MySQL are based on the "relational model" which is constructed from tables. IMS the database from IBM is based on a hierachical model. Etc.

Metasafe is based on an entity-relationship model, which means that is handles "entities" and "relationships between entities". This is the difference.

What do they have in common? A (proper) database can be used by many users in parallel. It guarantees that a set of changes (a transaction) is processed completely or not all to make sure that the database is allways in a consistent state. A DMBS has also an access language (in case of Metasafe erSQL) and an API to access the data in the database.