MGS351 Exam 2 review XCM C

Question 1

Relational Databases

Answer 1

-Stores data in the form of related tables

Question 2

Relational Design

Answer 2

-Based on normalization and can be accomplished by using ERD’s

Question 3

Benefits of Relational Databases and designs

Answer 3

(1) Making sure the data is good.
Example: Adding, Deleting, and updating records
(2) Powerful to use

Question 4

Principles of Design Relational Databases

Answer 4

(1) you must become a business expert
(2) knowing that Poor Relational Databases design lead to system failure
(3) Having a Proper design because this accurately reflects the organizations business rules
(4) Relational database is both an art and science (Cost-benefit)

Question 5

Entity Relationship Diagrams (ERD)

Answer 5

-Its a Diagramming tool to design a database (Blueprint)

Question 6

If the ERD is designed properly then…?

Answer 6

• The ERD will accurately reflect the the business rules of the organization.
• Visual illustration of the organizations business rules
• corrections are harder than adding on

Question 7

1:1

Answer 7

One to one

(1) Relationships merge into one table.
(2) Then one entity becomes an attribute for the other
- Example: The entities is “A single student” to a “single Id card”
- then it would be a a single “STUDENT” with an attribute of an ID card

Question 8

1:N

Answer 8

One to Many

• all relationships must be simplified to this!
  (1) make a primary key in the “One Entity” and make it the Foreign key for the “Many Entity”

Question 9

N:M

Answer 9

Many to Many

• Needs to be simplified to 1-N
  (1) Add an intersection table between the two tables
  (2) flip the lines so that the many faces the intersection table
  (3) Include the Primary keys from both tables into the intersection table as foreign keys.
  (4) make a name for the intersection table
  (5) add relevant Attributes(fields) to the table if necessary
  (6) make a primary key or auto-number in the intersection table

Question 10

Entities

Answer 10

• The rectangular shape
• Attributes stored in here (data)
• Correspond to Database tables

Question 11

Lines

Answer 11

Relationships between one another

Question 12

Attributes

Answer 12

• These are fields
• Descriptive value associated with an entity
• Corresponds to database fields in a table

Question 13

Key Attributes

Answer 13

• Correspond to Primary keys

- Uniquely identifies an entity

Question 14

What concept should be factored into relationships

Answer 14

-Time

Question 15

Database Normalization

Answer 15

The way Database design is taught in classrooms

• Learning process on how to use relationships
• Number of rules to the relationship model which would simplify relationships
  
  • Avoid common database problems
  • Make the data as tightly bound as possible
  • Store the minimum amount of data
• First, second, and third normal form

Question 16

Un-normalized vs. Normalized

Answer 16

Goal: The fields in a table depend on the key, the whole key, nothing but the key*

Question 17

Database normalization steps: 1NF

Answer 17

Remove repeating groups

Question 18

Database normalization step: 2NF

Answer 18

Remove fields that depend only on the key field.

-Applies to concatenate fields

Question 19

Database normalization step: 3NF

Answer 19

Remove fields that depend only on other fields