umlschemadatabase-schemaentity-relationship

ER (Entity Relationship) Diagram == Relational Schema Database?


I've been asked to model a relational database (ER) diagram using UML notation which should show the multiplicity, cardinality/participation of the relationships.

But then I'm asked to use the ER diagram and convert it to a relational database schema showing primary and foreign keys.

What is the difference between the two besides the addition of keys?


Solution

  • There a few more steps. If you have a M:N (or in UML notation, .... ) association then you would need to create an intermediate table to store the links ("instances") of that association in the database as a result of the normalization process.

    You must also normalize generalization relationships, association classes and a few other details.