There are several processes and algorithms
available to convert ER Diagrams into Relational Schema. Some of them are
automated and some of them are manual. We may focus here on the mapping diagram
contents to relational basics.
ER diagrams mainly comprise of −
- Entity and its attributes
- Relationship, which is association among entities.
Mapping
Process
- Create table for a relationship.
- Add the primary keys of all participating Entities as
fields of table with their respective data types.
- If relationship has any attribute, add each attribute
as field of table.
- Declare a primary key composing all the primary keys of
participating entities.
- Declare all foreign key constraints.