Author Question: A domain is the set of all data types and ranges of values that ________ may assume. A) Entities ... (Read 62 times)

jayhills49

  • Hero Member
  • *****
  • Posts: 559
A domain is the set of all data types and ranges of values that ________ may assume.
 
  A) Entities
  B) Instances
  C) Attributes
  D) Events

Question 2

Summarize the four steps involved in transforming an E-R diagram into normalized relations and then merging them into one consolidated set of relations.
 
  What will be an ideal response?


ricroger

  • Sr. Member
  • ****
  • Posts: 352
Answer to Question 1

C

Answer to Question 2

1. Represent entities. Each entity type in the E-R diagram becomes a relation. The identifier of the entity type becomes the primary key of the relation, and other attributes of the entity type become nonprimary key attributes of the relation. 2. Represent relationships. Each relationship in an E-R diagram must be represented in the relational database design. How we represent a relationship depends on its nature. 3. Normalize the relations. The relations created in steps 1 and 2 may have unnecessary redundancy. So we need to normalize these relations to make them well structured. 4. Merge the relations. So far in database design we have created various relations from both a bottom-up normalization of user views and from transforming one or more E-R diagrams into sets of relations. Across these different sets of relations, there may be redundant relations (two or more relations that describe the same entity type) that must be merged and renormalized to remove the redundancy.



Related Topics

Need homework help now?

Ask unlimited questions for free

Ask a Question
 

Did you know?

There are more bacteria in your mouth than there are people in the world.

Did you know?

Amoebae are the simplest type of protozoans, and are characterized by a feeding and dividing trophozoite stage that moves by temporary extensions called pseudopodia or false feet.

Did you know?

Only one in 10 cancer deaths is caused by the primary tumor. The vast majority of cancer mortality is caused by cells breaking away from the main tumor and metastasizing to other parts of the body, such as the brain, bones, or liver.

Did you know?

Of the estimated 2 million heroin users in the United States, 600,000–800,000 are considered hardcore addicts. Heroin addiction is considered to be one of the hardest addictions to recover from.

Did you know?

Atropine, along with scopolamine and hyoscyamine, is found in the Datura stramonium plant, which gives hallucinogenic effects and is also known as locoweed.

For a complete list of videos, visit our video library