Section 6: Data

Question 1

Why do we need Database Management Systems? (DBMS)

Answer 1

It allows the organization to access and store all of its data for each employee so it can be easily accessed

Question 2

Why do we need database research?

Answer 2

It allows for organizations to analyze data and make better business decisions

Question 3

How are databases and the World Wide Web interconnected?

Answer 3

Websites interface between clients and databases, responding to client requests.

(Client sends a request to the server, the web servers search a database, organize the results in a web page, finally it sends that page to the client)

Question 4

How many layers are in the DBMS?

What are they and explain what they do.

Answer 4

1) Application Layer - Communicates w/ the end user and can be fairly complex (Receives request, sends request to DBM Layer)

2) Database Management Layer - Holds data in data tables (records and fields) as well as fulfills requests sent by application layer.

Question 5

What are records and fields in a data table?

Answer 5

Records = Rows

Fields = Columns

Question 6

Name the different types of Data.

Answer 6

Integers - Whole Numbers (1,2,3,4)

Floating Point Numbers - Numbers stored as decimals (1.34, 2.67)

Characters - Letters and other types of characters (D, #, l , k , !)

Character Strings - String or combination of Characters (dsfoihei!@#$Ssfd#)

Boolean Values - Yes or No values (True / False)

Question 7

What is a flat-file database?

How does it store data?

Answer 7

A simple data table. A flat-file database can not contain multiple tables

Stores data as a plain text file

Question 8

What is a hierarchical database?

Answer 8

Stores data in a tree like structure. There is one parent for each record.

Question 9

What is a segment in a hierarchical databse?

Answer 9

It is an optional node that forms a sub-tree

Question 10

What is a relational database?

Answer 10

Tables that can be joined in logical ways.

Question 11

What is a primary key?

Answer 11

A unique identifier that creates the relationship among tables. Typically a field not record

Question 12

What is a foreign key?

Answer 12

When a primary key is marked on one table but is also found on another table. That second primary key is the foreign key.

Question 13

What are Object-Oriented databases (OO)?

Answer 13

Stores complex data and relationships between data directly w/out user inter-table relations

Question 14

What are NoSQL databases?

Answer 14

Not only SQL.

Can accommodate a wide variety of data models
- Key-value
- document
- columnar
- graph formats

Question 15

What are graph stores?

Answer 15

Used to store information about networks of data (social connections)

Question 16

What are wide-column stores?

Answer 16

Stores are optimized for queries on large data sets and store columns of data together, instead of in rows

Question 17

What is a document-format database

Answer 17

Pair each key with a complex data structure known as a document (Documents can contain many different key-value pairs)

Question 18

What are distributed databases?

Answer 18

Consists of data residing on different machines

Question 19

What are SQL statements used for?

Answer 19

Queries that identify what data should be retrieved or how the data should be manipulated

Question 20

How does SQL and the database server interconnect?

Answer 20

DBMS provides a mechanism to send the code to and from the database server

Question 21

What does the selection operation do?

Answer 21

Takes rows from one table and creates a new table

Question 22

What does the keyword ‘SELECT’ do?

Answer 22

Identifies the records that are being requested

Question 23

What does the keyword ‘FROM’ do?

Answer 23

Identifies the table name

Question 24

What does the keyword ‘WHERE’ do?

Answer 24

The condition the query is requesting

Question 25

What does the ‘*’ do?

Answer 25

Everything from the table is selected

Question 26

What is the ‘UNION’ operation?

Answer 26

Combines distinct fields from multiple tables that have the same set of attributes and data types

Question 27

What is the ‘PRODUCT’ operation?

Answer 27

Creates a result table that includes all of the attributes from the two tables

Question 28

What is the ‘JOIN’ operation?

Answer 28

Combines two tables, but records are only appended when a matching criterion is met

Question 29

What are the DBA responsibilities?

Answer 29

1) Security

2) Tuning

3) Availability

4) Continuity

5) Backup and recovery

6) Reporting

7) Design and develop database applications

Question 30

What is business intelligence?

Answer 30

Using collected data to assist in making predictions and decisions that will increase profits.