Author Question: Which of the following properties should be satisfied when the identifier of the entity type becomes ... (Read 56 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?

Sperm cells are so tiny that 400 to 500 million (400,000,000–500,000,000) of them fit onto 1 tsp.

Did you know?

Although the Roman numeral for the number 4 has always been taught to have been "IV," according to historians, the ancient Romans probably used "IIII" most of the time. This is partially backed up by the fact that early grandfather clocks displayed IIII for the number 4 instead of IV. Early clockmakers apparently thought that the IIII balanced out the VIII (used for the number 8) on the clock face and that it just looked better.

Did you know?

In women, pharmacodynamic differences include increased sensitivity to (and increased effectiveness of) beta-blockers, opioids, selective serotonin reuptake inhibitors, and typical antipsychotics.

Did you know?

Illness; diuretics; laxative abuse; hot weather; exercise; sweating; caffeine; alcoholic beverages; starvation diets; inadequate carbohydrate consumption; and diets high in protein, salt, or fiber can cause people to become dehydrated.

Did you know?

By definition, when a medication is administered intravenously, its bioavailability is 100%.

For a complete list of videos, visit our video library