I know it is possible to convert the entity relationship to a relational model but is it possible to convert the relational model to entity relationship using the same rules? I have looked for it in the internet but people always convert from ER to Relational.
Asked
Active
Viewed 193 times
1 Answers
2
The entity-relationship model is a thin interpretation over the relational model. Entity sets are the domains of attributes, value sets are the codomains of attributes, relationship sets are relations over multiple entity sets, and attributes are 1-to-1 binary relations from entities or relationships to values. Any entity-relationship model (and I would venture to say, any data model) can be understood in terms of its domains and relations.
Starting from a relational model, not every relation necessarily conforms to the characteristics of an entity relation or a relationship relation. The relational model doesn't distinguish entities from values, hence is a simpler and more general model of data. However, it's not difficult to normalize, then combine attributes on common determinants to create entity relations and create relationship relations from relations over multiple entities.
reaanb
- 9,806
- 2
- 23
- 37