What is Tips on Data Modeling? , What is Mapping a Class Diagram into an ERD ?

What is Tips on Data Modeling? 

 What is Mapping a Class Diagram into an ERD ?

Tips on Data Modeling

- Use an automated tool, preferably the one that your chosen DBMS provides, for your data model.

- Apply normalization rules and normalize your database design at least to the 3rd Normalization form or to

BCNF.

- Use understandable names for relations/tables and attributes/fields.

- Use proper data types and apply DBMS provided restrictions and rules such as Not Null.

- Use proper naming for Foreign Keys and Relationships.

- Check your design by providing data through DBMS interface and control the expected outputs by running

some Structured Query Language (SQL) commands on the provided data.

If you follow an ordinary (structured) methodology, then you would provide an Entity Relationship Diagram (ERD). You can use this diagramto provide a normalized data model, afterwards. However, if you follow object-oriented methodology then you should know how you could map your class model to an ERD. Most of IDEs and development tools are providing tools, add-ons, and facilities to help in the mapping process. If you are using one of these tools then your job is easier. Simply use the facilities that they provide. However, if you do not have an automated tool to do so, below you can find some rules of thumb for mapping a class model into an ERD, manually.

Mapping a Class Diagram into an ERD

- Indicate your persistent class, e.g. by using a persistent stereotype.

- Create an Entity for any persistent class, giving the name of the class.

- Map all data members of the class as attributes of the created Entity.

- Give the same, or equivalent, data type to the attributes.

- Make the class identity (ID) the Primary Key for the Entity.

- Map associations, aggregations, and compositions to relationships and use class IDs as Foreign Keys.

- Change generalization/specialization relations of the class model to superclass/subclass relations and apply

ERD rules, accordingly.

- Map multiplicities of associations to the equivalent cardinalities in the ERD.