1. Draw an entity-relationship diagram of a patient–doctor relationship. a. Which of the types of E-R diagrams is it?
b. In a sentence or two, explain why the patient–doctor relationship is diagrammed in this way.
I believe that this is a bit open to interpretation and that one doctor may have many patients and one patient may have more than one doctor. As well as patients can choose their doctors and vice versa.
This is a simple ERD where the diag. shows a 0-many optional relationship between both doctors and patients.
2. You began drawing E-R diagrams soon after your entry into the health maintenance organization for which you’re designing a system. Your team member is skeptical about using E-R diagrams before design of the database is begun. In a paragraph, persuade your team member that early use of E-R diagrams is worthwhile.
The entity-relationship diagram is a tool for designing and analyzing databases, and in particular for applying a technique called entity-relationship (ER) modeling to the design process. It has proven to be very successful at rendering the relationships among the data fields, or variables, contained within a given database. Using the graphically very well arranged Entity Relationship Diagrams (ER Diagrams) you can easily create and maintain your database structures. In your models you will have all the entities, attributes, domains, primary keys, foreign keys, constraints, relationships, also notes and other physical and logical data, laid-out in a transparent order. While creating models you will have a perfect view of all database elements. You can simply set the values of all attributes, types of relationships and other criteria, as for example indexes, etc The most significant benefits are related to the following areas: •
Professional and faster development
Fewer faults in development
Very efficient maintenance
Work with already existing database structures
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