Reference no: EM131106263
Please include the questions with your answers. Answer in complete sentences where applicable.
1. A database is a model of a user's view of the world. We must ask ourselves "How well does it fit the mental models of the people who are going to use the system?" Discuss why it's important that the model fits the user requirements, even if the developer "knows better."
2. Write the SQL SELECT statement to display the property type, rooms, and rent sorted by the Type.
Use the following PROPERTY table to answer the question:
|
PropertyID
|
Type
|
Rooms
|
Rent
|
|
306
|
Apt
|
3
|
550
|
|
308
|
House
|
6
|
1000
|
|
325
|
Apt
|
4
|
625
|
|
397
|
Apt
|
3
|
550
|
|
412
|
House
|
7
|
1250
|
|
441
|
Apt
|
2
|
475
|
3. Write the SQL SELECT statement to display the average rent of the properties.
Use the following PROPERTY table to answer the question:
|
PropertyID
|
Type
|
Rooms
|
Rent
|
|
306
|
Apt
|
3
|
550
|
|
308
|
House
|
6
|
1000
|
|
325
|
Apt
|
4
|
625
|
|
397
|
Apt
|
3
|
550
|
|
412
|
House
|
7
|
1250
|
|
441
|
Apt
|
2
|
475
|
4. What is normalization? Explain why it is important.
5. List and describe the 4 components of a database system.
6. Give an example of a data constraint and an example of a business rule. Be sure to label which is which so I can tell you know the difference.
7. Explain the difference between an entity class and an entity instance, and give an example other than those used in the text or the lectures.
8. Define the term "weak entity" and give an example other than those used in the text.
9. Define supertype, subtype and discriminator.
10. Explain the difference between and inclusive subtype relationship and an exclusive subtype relationship.
11. Using Microsoft Visio 2013 (available through DreamSpark) draw an IE Crow's Foot E-R diagram for the entities DEPARTMENT and EMPLOYEE. A DEPARTMENT may have more than one EMPLOYEE, but an EMPLOYEE is only assigned to one DEPARTMENT. Assume that a DEPARTMENT does not need to have an EMPLOYEE, but that every EMPLOYEE is assigned to a DEPARTMENT. Include at least three appropriate identifiers and attributes for each entity.
12. Explain the following crow's foot E-R diagram. Be sure to include entities, keys, attributes, cardinality. What is the special type of entity represented by COMMISSION_RATE?
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Amortize premium or discount on interest dates
: Sanford Co. sells $500,000 of 10% bonds on March 1, 2010. The bonds pay interest on September 1 and March 1. The due date of the bonds is September 1, 2013. The bonds yield 12%. Give entries through December 31, 2011.
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Explain the impact of databases on businesses
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What would be the effective cost of the bank loan
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Same recommendation on which machine to purchase
: Simulate the system in Problem 10. Make any assumptions about the warm-up time and run time you believe are appropriate. Try solving the problem with exponentially distributed copying times.
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What is normalization and explain why it is important
: Write the SQL SELECT statement to display the average rent of the properties. What is normalization? Explain why it is important. List and describe the 4 components of a database system.
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Within an arm reach of desire
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Show that every compact metric space is separable
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How much capital would be released
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Use the simulation outputs to estimate total system costs
: Given the model in the Multi server Simulation.xlsm file, what unit cost parameters should be used if we are interested in "optimizing" the system?
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