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

Author Question: What are the roles of aggregation and association in relational database? What will be an ideal ... (Read 36 times)

notis

  • Hero Member
  • *****
  • Posts: 596
on: Jul 7, 2018
What are the roles of aggregation and association in relational database?
 
  What will be an ideal response?

Question 2

Design patterns are usually classified based on the type of the problems that they address.
 
  Indicate whether the statement is true or false


Related Topics

Need homework help now?

Ask unlimited questions for free

Ask a Question
Marked as best answer by a Subject Expert

fraziera112

  • Sr. Member
  • ****
  • Posts: 356
Reply #1 on: Jul 7, 2018
Answer to Question 1

To map to a relational database, aggregation must be flattened into association; that is, the relational model is flat: tables do not own each other and are not composed of each other. This means that aggregation and composition relationships must be changed to association to map to tables. The task is not complicated: the table for the aggregate class provides the primary key, the tables for aggregating classes implement the foreign keys, and the multiplicity stays the same.

Answer to Question 2

TRUE


notis

  • Member
  • Posts: 596
Reply 2 on: Jul 7, 2018
Excellent

ryhom

  • Member
  • Posts: 366
Reply 3 on: Yesterday
Wow, this really help

« previous next »
 

Did you know?

Intradermal injections are somewhat difficult to correctly administer because the skin layers are so thin that it is easy to accidentally punch through to the deeper subcutaneous layer.

Did you know?

Prostaglandins were first isolated from human semen in Sweden in the 1930s. They were so named because the researcher thought that they came from the prostate gland. In fact, prostaglandins exist and are synthesized in almost every cell of the body.

Did you know?

When blood is exposed to air, it clots. Heparin allows the blood to come in direct contact with air without clotting.

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?

It is difficult to obtain enough calcium without consuming milk or other dairy foods.

The gender roles that we learn during childhood become part of our basic orientations to life. ... The gender roles that we learn during childhood become part of our basic orientations to life. ...
PMDD Diagnostic Criteria from the American Psychiatric Association PMDD Diagnostic Criteria from the American Psychiatric Association
Association of Different HLA Alleles and Increased Susceptibility to Autoimmune Diseases Association of Different HLA Alleles and Increased Susceptibility to Autoimmune Diseases
Polyamines for cell proliferation because of their roles in stabilizing duplex DNA structure Polyamines for cell proliferation because of their roles in stabilizing duplex DNA structure
If CP for an ideal gas is 35.4 J/molK, which of the following is CV for this gas? If CP for an ideal gas is 35.4 J/molK, which of the following is CV for this gas?
A gene map for chromosome 12 from the NCBI database Map Viewer A gene map for chromosome 12 from the NCBI database Map Viewer
Video: Gastrin (gastric emptying) & Secretin (buffering gastric acid)

For a complete list of videos, visit our video library