Author Question: Which of the following properties should be satisfied when the identifier of the entity type becomes ... (Read 53 times)

Tazate

  • Hero Member
  • *****
  • Posts: 532
Which of the following properties should be satisfied when the identifier of the entity type becomes the primary key of the corresponding relation?
 
  A) The value of the key must uniquely identify every row in the relation.
  B) The key should serve as a foreign key in at least two other relations.
  C) The key must be a composite of a primary key and a secondary key.
  D) The key should be an intelligent key.
  E) The key should allow for null values.

Question 2

Modeling deliverables from project activities using object-oriented modeling include:
 
  A) structure charts and data flow diagrams.
  B) dialogue diagrams and object reference charts.
  C) decision tables and object status diagrams.
  D) data-flow and entity-relationship diagrams and repository descriptions.
  E) dialogue diagrams, Structured English representations, and structure charts.



bpool94

  • Sr. Member
  • ****
  • Posts: 354
Answer to Question 1

A
Explanation: A) A primary key is an attribute whose value is unique across all occurrences of a relation.
CL

Answer to Question 2

D
Explanation: D) Unique to UML is how tightly linked these three deliverables are to each other.
CL



Related Topics

Need homework help now?

Ask unlimited questions for free

Ask a Question
 

Did you know?

Approximately one in three babies in the United States is now delivered by cesarean section. The number of cesarean sections in the United States has risen 46% since 1996.

Did you know?

According to animal studies, the typical American diet is damaging to the liver and may result in allergies, low energy, digestive problems, and a lack of ability to detoxify harmful substances.

Did you know?

Thyroid conditions cause a higher risk of fibromyalgia and chronic fatigue syndrome.

Did you know?

About 100 new prescription or over-the-counter drugs come into the U.S. market every year.

Did you know?

Patients should never assume they are being given the appropriate drugs. They should make sure they know which drugs are being prescribed, and always double-check that the drugs received match the prescription.

For a complete list of videos, visit our video library