What role does the entity-relationship (ER) diagram play in the design process?

What role does the entity-relationship (ER) diagram play in the design process? Discuss the different types of information represented in the ER diagram and the symbols used to represent them. Discuss the meaning of an entity as related to ER diagrams. How would you approach the diagramming process?

 

ANSWER

When designing database tables, the difference between a good design and a bad design can be a few seconds in response time and several minutes. You may think that this is not a huge difference, but imagine waiting several minutes on a web page for your results to load. How long would you wait? A slow database can mean the loss of customers. So let’s begin by discussing some of the common elements of tables and how you would approach the table design. What would you do to ensure that your page loads in a few seconds? Discuss the relationship types and how they affect your design.