Entity Relationship Model

Also known as ER modelling. “The entity-relationship model (or ER model) is a way of graphically representing the logical relationships of entities (or objects) in order to create a database.”

ER model is used by designers and software engineers to create a visual representation of how the architecture of the website or application will work in a database. Designers and software engineers create a Entity relationship diagram in order to create a visual representation. Entities are rendered into points, ovals, circles and polygons. Relationship between the entities is portrayed in lines connecting the points between ovals, circles and polygons. ER diagram are used for design optimization and debugging of the database programs. 

For our homework we had to create a ER model and a ER diagram for our website application. I have also created a physical database design using dummy data to test it.

rsz_edr

This physical database design allows me to test how the database will work. In order for a user to submit a day out he will have to register. We request username, password and email in order for the user to register. The Next step the user has to do is to log_in there is no need to create another table for logging in but I did as it is easier for me to visualize how it works. To log in the user has to insert his user name and password the information is checked by the user_id. If there is a user_id which such data in the database the user will be able to log in if not a message of “Please Register”  will pop up.

When the user is logged in he will be able to submit a day out. He will have to input the name, description, location and the rating of the day out.

I have also created a ER diagram. Which visualize how the database works:

rsz_edr_-_new_page

Looking at this diagram (reading it from left to right to bottom) we can see that each User can have one or more day out’s submitted and that each day out submitted must be owned by one and only one user. To Read my ERD I have used “Richard Barker’s Case*Method: Entity Relationship Modelling.” To create a ER Diagram I have used an online tool -https://www.lucidchart.com

References: 

http://folksonomy.co/?permalink=1454

http://searchsqlserver.techtarget.com/definition/entity-relationship-model

 

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