Assignment: Database Modeling Practice with your Classmates
As a continuance of Requirements Elicitation (M2D1), this discussion. Everyone knows that practice makes perfect, so you will spend your discussion doing a database design "dry run" before working on your this week. It's important to be as real as possible in this exercise to get the most out of it. Put yourself in the role of a systems analyst or client, as this practice will help you not only in the assignment this week, but also in your future professional work.
Step 1 (as Stakeholder/Customer)
In your initial message, assume the role of the Stakeholder/Customer and post a summary of previous module's discussion on Requirements Elicitation (M2D1) with your classmates. Include the following:
• A summary of the interview discussions regarding your needs and identified data requirements
• Based on the entities/attributes suggested by your classmates during M2D1 as well as the concepts you learned in module 3, create the final list of entities and attributes. For each entity, specify the identifier.
o If you did not receive interview questions in M2D1, create a list of entities/attributes that address the needs specified in your M2D1 initial message.
• A reflection on last week's requirements gathering and analysis process. Do you think the entities/attributes identified by your classmates (as database analysts) address your data management needs? If yes, how? If not, why? Based on what you learned in Module 2 and Module 3, are there changes you want to make to entities/attributes identified by them? If so, what? If you had to re-start the data gathering process, what are the interview questions you would suggest your classmates as database analysts to add?
o If you did not receive interview questions in M2D1 and you had to come up with the entities and attributes by yourself, discuss if the requirement elicitation and entity/attribute identification practices in M2D1, as well as the new concepts introduced in module 3, helped you refine your data management needs? If yes, how? If not, why?
Step 2 (as System Analyst)
Please use the IE table/relation notation (also called crow's foot notation) specified in (Harrington, 2009, p. 70-71) to create the ER diagram.
1. Based on the database needs of your classmate and the entities/attributes defined, suggest the relationships between the entities and their types (1:M, 1:1, M:N). If there is a M:N relationship, suggest a new, composite entity (also called associative entity) that represents the M:N relationship.
2. Using Microsoft Visio or an open source alternative such as Dia, create an entity-relationship diagram for the specifications your classmate (stakeholder/customer) posted. Keep the module notes, readings, and the following in mind when assembling your diagram:
• All entities should have an identifier/primary key
• All attributes should be scalar (i.e., have one and only one value)
• All attributes should have an appropriate data type
• Relationships should be clearly notated with their cardinalities (you may need to create new attributes as foreign keys in order to specify relationships)
• You should convert M:N relationships to composite entities
• There might be weak entities in the diagram
Take a screenshot of your diagram and upload the image file as an attachment to your . In your response post, please also describe the diagram you created (such as how entities are related, how can a record in an entity can be uniquely identified, - see the module notes and videos for examples on how to justify and explain your reasoning for making certain design decisions).
If your classmate's (stakeholder/customer) database specifications are incomplete so that you cannot create a complete ER diagram, ask additional questions that will help you finish your diagram.
Step 3 (as Stakeholder/Customer)
In your role as Stakeholder/Customer, if there are follow-up questions and ER designs from your classmates (as system analyst) in their responses to your initial message, respond to them. Consider the following questions: Were the entities, attributes, data types, keys, and relationships appropriate? Are there potential data anomalies in your classmates' design(s) as specified in chapter 3 of Harrington (2009)? Is there anything you would have done differently? If so, post your design and point out how (if at all) it differs from your classmate's. Offer an explanation for why these differences exist. Who is correct? Are you both correct? Why?