This topic contains a solution. Click here to go to the answer
« previous next »

Author Question: To build an information system, which one do you need to identify first classes or objects? What ... (Read 26 times)

khang

  • Hero Member
  • *****
  • Posts: 569
on: Jul 7, 2018
To build an information system, which one do you need to identify first classes or objects?
 
  What will be an ideal response?

Question 2

Explain foreign keys are they necessary?
 
  What will be an ideal response?


Related Topics

Need homework help now?

Ask unlimited questions for free

Ask a Question
Marked as best answer by a Subject Expert

Melissahxx

  • Sr. Member
  • ****
  • Posts: 304
Reply #1 on: Jul 7, 2018
Answer to Question 1

The process of classification  that is, definition of classes  starts with a concept: a general idea that is shaped into a distinct class through a mental and semantic process of generalization. In other words, the concept always precedes classification, regardless of whether existing objects give rise to a class or the objects are created from a class.

Answer to Question 2

The relationship between entities in different tables is established through foreign keys. The foreign key is an attribute in one table, the value of which must match the value of a primary or an alternate key in another table. Unlike primary keys, foreign keys are not required and do not, necessarily, identify a row uniquely. Like primary keys, a foreign key can be composite, consisting of more than one attribute.


khang

  • Member
  • Posts: 569
Reply 2 on: Jul 7, 2018
YES! Correct, THANKS for helping me on my review

zacnyjessica

  • Member
  • Posts: 345
Reply 3 on: Yesterday
:D TYSM

« previous next »
 

Did you know?

During the twentieth century, a variant of the metric system was used in Russia and France in which the base unit of mass was the tonne. Instead of kilograms, this system used millitonnes (mt).

Did you know?

The National Institutes of Health have supported research into acupuncture. This has shown that acupuncture significantly reduced pain associated with osteoarthritis of the knee, when used as a complement to conventional therapies.

Did you know?

According to the National Institute of Environmental Health Sciences, lung disease is the third leading killer in the United States, responsible for one in seven deaths. It is the leading cause of death among infants under the age of one year.

Did you know?

It is important to read food labels and choose foods with low cholesterol and saturated trans fat. You should limit saturated fat to no higher than 6% of daily calories.

Did you know?

Amphetamine poisoning can cause intravascular coagulation, circulatory collapse, rhabdomyolysis, ischemic colitis, acute psychosis, hyperthermia, respiratory distress syndrome, and pericarditis.

The central nervous system The central nervous system
Children with autism generally prefer interacting with objects over people. Children with autism generally prefer interacting with objects over people.
Effects of the Autonomic Nervous System Effects of the Autonomic Nervous System
Bod Pod: Body Composition Tracking System Bod Pod: Body Composition Tracking System
The Vascular System The Vascular System
Organs of the human male reproductive system, their functions, and locations. Organs of the human male reproductive system, their functions, and locations.
Video: Cognitive development by Piaget (Preoperational stage or intelligence)

For a complete list of videos, visit our video library