The primary difference between DBMS and RDBMS is, in RDBMS we have relations between the tables of the database. Whereas in DBMS there is no relation between the tables(data may even be stored in files).
RDBMS has primary keys and data is stored in tables.
DBMS has no concept of primary keys with data stored in navigational or hierarchical form.
RDBMS defines integrity constraints in order to follow ACID properties. While DBMS doesn't follow ACID properties.