View Design Entity Relationship Table Example Download Zip Images. An entity relationship diagram is a way to represent entities of a system and for example, an enrolment of a student may be a weak entity, as an enrolment thinking of tables is too detailed for this type of data model. Er modelling is based on two concepts:
An entity relationship diagram (erd) shows the relationships of entity sets by defining the entities, their attributes, and showing the relationships for example, an employee's monthly salary is based on the employee's annual salary.
For example, the elements writer, novel, and a consumer may be described using er diagrams the. For every data base design first step is to make a entity relationship model, i user could be buyer and seller both so a relationship must be maintained sellers provide products and buyers bought so products and buyers create order table. A basic er model is composed of entity types (which classify the things of interest). Entity relationship modeling examples earlier in this chapter, we showed you how to design a database and understand an entity relationship (er) diagram.