Week 2

Question 1

The diagram that identifies the entities in the database and shows how they are related (logical representation) is called what?

Answer 1

E-R Model (Entity-relationship model)

Question 2

What are the 3 relationship types in a database?

Answer 2

One-to-One
One-to-Many
Many-to-Many

Question 3

Why is database normalization used?

Answer 3

To reduce/eliminate data redundancy and avoid anomalies

Question 4

This identifies each record

Answer 4

Primary Key

Question 5

When more than 1 field is needed to uniquely identify a record, what type of key is used?

Answer 5

A composite primary key

Question 6

When a composite primary key is used, but a record only depends on part of the primary key, what occurs?

Answer 6

Partial dependency

Question 7

When at least 1 value in a record isn’t dependent on the primary key, but on a different field, it is what?

Answer 7

Transitive dependency

Question 8

What does the 1NF in normalization do?

Answer 8

eliminates all repeating values and identifies a primary or primary composite key

Question 9

What does the 2NF in normaliztion do?

Answer 9

Makes sure the table is in 1NF and eliminates partial dependencies

Question 10

What does the 3NF in normaliztion do?

Answer 10

Makes sure the table is in 2NF and removes any transitive dependencies

Question 11

This key is used to establish a relationship between tables and is a primary key in one of the tables. It’s usually on the many side of a relationship.

Answer 11

Foreign Key

Question 12

Since many-to-many relationships can’t exist in a relational database, a _____ is used to create two one-to-many relationships.

Answer 12

bridging entity

Question 13

A table that references the foreign key to show what a particular value is.

Answer 13

Lookup table

Question 14

This is the language used to create database objects and manipulate data stored in a database.

Answer 14

Structured Query Language (SQL)

Question 15

What is the difference between a query and a transaction?

Answer 15

Query- causes data to be retrieved

Transaction- causes data to to read and written (updating, creating, deleting objects)

Question 16

The ability to change the structure of the data without having to change the program to access the data is called what?

Answer 16

program-data independence

Question 17

The ability to change an operation in the data without having to change the interface used to process the operation is called what?

Answer 17

program-operation independence

Question 18

A ___ is the difference perspectives that different users need to see the data.

Answer 18

View

Question 19

An ____ is based on tree data structures or hash data structures that are suitably modified for disk search.

Answer 19

Index

Question 20

When every A record must be related to a B record, it is called what?
(A section record must be related to a course record)

Answer 20

Referential integrity

Question 21

Rules or definitions for the data in a database.

Answer 21

Integrity constraint

Question 22

A collection of concepts that is used to describe the database structure (data types, relationships, constraints, etc) is called what?

Answer 22

Data model

Question 23

An ___ represents a real-world concept or object.

Answer 23

Entity

Question 24

Data that further describes an entity.

Answer 24

Attribute

Question 25

What data is in the database at a given point in time.

Answer 25

Database state, instance.