Although, the essential features of E-R diagrams are enough to design many database situations. Though, with more difficult relations and advanced database applications, it is need to move to enhanced features of E-R models. The three such features are:
In this part, we have described them with the help of an example. More detail on them are available in the further readings and MCS-043.
Example: A bank has an account entity set. The accounts of the bank can be of two parts:
The statement as above shows a specialisation/generalisation hierarchy. It can be shown as
Figure: Generalisation and Specialisation hierarchy