Mis582 all week discussions latest 2017 (except week 1 & 5 discussions)
Subject: General Questions / General General Questions
Week 2 discussion
Normalizing the Database
Consider the following entity and its attributes. INVOICE (Number, Customer Name, Customer Number, Customer Address, Item Number, Item Price, Item Quantity, Sales Person Number, Sales Person Name, Subtotal, Tax, Total Due)
What issue does this entity have that can be solved by normalization?
What functional dependencies exist between the attributes?
How would you apply normalization to break this into more than one entity, each with a single theme?
The Different Normal Forms
Many texts and articles will state that normalization to 3NF is sufficient.
Are there database environments that would require normalization to a higher normal form?
How about environments that do better when is there normalization to a lower normal form?
Why do you think there are so many different normal forms to choose from?
Week 3 discussion
Data Modeling Patterns
The textbook talks about the relationships between user forms and reports and their underlying database structure. There are well-known structures used in forms and reports that translate into well-known patterns that appear regularly in an ERD (entity relationship diagram) database model.
Describe one of these data modeling patterns, along with an example of when it would be used. Do not use the examples given in the textbook.
Have you seen any of these well-known patterns in forms or reports that you have encountered at work or on the Internet? Give an example and explain what it lets you infer about the underlying structure of the database behind it.
Entity Types and Relationships
There are many kinds of entity relationships in a database model. The relationships can be classified by the following things.
Cardinality: maximum and minimum
Degree: binary, ternary, degree 4, and so forth
Entity type: strong, weak, ID-dependent, and supertype/subtype
What are these different types of classifications? Do they overlap, or do they each tell us something unique about the entity relationship? Why is it important to classify each of these types in an ERD (entity relationship diagram) model?
Week 4 discussion
Entity and Table Relationships
When creating relationships between tables in our database, we must consider the following entity relationships.
Non-identifying relationships between strong entities
Identifying relationships between ID-dependent entities
Mixed-entity pattern relationships
Supertype and subtype relationships
Create an example of entities in one of these relationships and describe how the entity pattern is transformed into database tables.
Referential Integrity Actions
Representing minimum cardinality in a physical database design can be tricky depending on whether the parent-child relationship is O-O, M-O, O-M, or M-M. Give an example of one of these minimum cardinalities and how it would affect the physical database design. What are referential integrity actions, and how could you use them in your example?
Week 6 discussion
Business requirements are enforced by implementing database constraints on tables and columns. The database constraints available include the following.
FOREIGN KEY or REFERENTIAL INTEGRITY
Give a business requirement and the constraint that could be implemented to enforce it. Explain the constraint you chose, and give the SQL to implement the constraint in the database.
What are the long-term problems when these constraints are not implemented?
After your database was put into production, a design flaw was discovered! One of the relationships modeled as a 1:N relationship was really an N:M relationship. The database issue involves the following tables, with PK italicized and underlined.
VEHICLE (VIN, Make, Model, Color, LicenseTag)
DRIVERS (DriverLicenseNo, LastName, FirstName, Address, Zip, VIN)
ZIPCODE (Zipcode, City, State)
Which 1:N relationship should be an N:M relationship? How would you redesign the database to correct the issue? What else must you consider when updating the structure of your database tables?
Week 7 discussion
Databases are designed to allow multiple users to have concurrent access to data. Yet this capability presents certain problems. Investigate how databases resolve multiple concurrent data management issues, including lost updates, deadlocks, and different types of lock management styles. Compare the different locking capabilities of Microsoft Access to one other database product.
Post your analysis in the thread. Do not cut and paste from the Internet. You should also respond to other posts to add additional information, clarify points, or answer questions.
Databases for Business Intelligence
We’ve been focusing on operational databases, often called online transaction processing (OLTP) systems. These OLTP systems handle the day-to-day business of the company and are accessed by multiple users simultaneously, updating the data in short transactions.
Business intelligence systems are sometimes called online analytical processing (OLAP) systems. These OLAP systems are used to make decisions and are characterized by few users submitting long-running queries that do not update the database to analyze the historic data of the company. What are some other differences between OLTP and OLAP systems? How are data warehouses similar or different from these two database models?