Chapter 1

Question 1

What is a database and what is it from the beginning?

Answer 1

A database is a collection of data, it is just a table. Once you put it in the table, a database is created.

Question 2

What do you need in order to control a database?

Answer 2

In order to get it controlled, we need DBMS. DBMS is a software.

Question 3

What is an example of a manually maintained database?

Answer 3

Shopping list

Question 4

What is an example of a computerized database?

Answer 4

Bank account data

Question 5

What are the tasks of DBMS?

Answer 5

*Data Definition Language (DDL), when creating a database, need to decide how many rows and columns that are needed for the table. Can add/delete from the table itself. (Table)

*Data Manipulation Language (DML), for example adding/remove/modifying the data. It is about the data. (Data)

*Database Querying, retrieving required data from the database. Required means based on condition. Ex. “attendance >5”.

Database Control, how to control the database. Who sees what/who has access to it?

Question 6

What are the purposes of database languages?

Answer 6

Communicate.
Retrieve data from the database.
Add data to the database.
Modify data in the database.
Delete data from the database.

Question 7

What is data?

Answer 7

Raw facts. Ex. “How many students in the class?”

Have not yet been processed to reveal their meaning to the end user

Question 8

What is data management?

Answer 8

Generation, storage, and retrieval of data

Question 9

What is information?

Answer 9

Produced by processing raw data to reveal its meaning.
Requires context.
Should be accurate, relevant, and timely to enable good decision making.

Question 10

What does database definition mean?

Answer 10

*Creating new database and tables
*Alter existing tables in the database
*Drop existing database and tables

Question 11

What does database manipulation mean?

Answer 11

*Adding new data to the database
*Modifying existing data in the database
*Deleting existing data from the database

Question 12

What is Database Querying?

Answer 12

Querying means retrieving required data from the database.

For example, you may want to retrieve “name and ID number of students” from the database.

Question 13

What is Database Control?

Answer 13

*Limiting access to data only to authorized users
*Sharing data among the users in such a way that database integrity is maintained

Question 14

What are the elements of the database approach?

Answer 14

Entities, Relationships,Data models

Question 15

What is an entity?

Answer 15

Noun form describing a person, place, object, event, or concept

Composed of attributes

Question 16

What are Relationships?

Answer 16

Between entities

Usually one-to-many (1:M) or many-to-many (M:N), or one-to-one (1:1)

Question 17

What are the Main data models used by most of the DBMS?

Answer 17

Network Data Model

Hierarchical Data Model

Relational Data Model

Question 18

How can the relationship in the Network Data model be?

Answer 18

Binary type or Many to one

Question 19

How can the relationship in the Hierarchical Data model be?

Answer 19

Data is in collections of records. Relationships are represented as sets. A restricted type of Network Data Model.

Each Record Type can have only one Parent and thus hierarchy.

Question 20

How can the relationship in the Relational Data model be?

Answer 20

Data and relationships are represented using tables. Data items are represented as columns of tables. A relational data model based database consists of one or more tables.

A relationship between every table. Will get information from the other table, through the relationship.

Question 21

What is Metadata?

Answer 21

Describes the data characteristics and the set of relationship that links the data found within the database. For example, the type of values (numeric, text…) stored on each data element, and whether the data element can be left empty.

Question 22

What are the roles of DBMS?

Answer 22

Might be written using: Visual Basic, Java, or C#.

Intermediary between the user and the database.

Enables data to be shared.

Presents the end user with an integrated view of the data.

Receives and translates application requests into operations required to fulfill the requests.

Hides database’s internal complexity from the application programs and users.

Question 23

What are the advantages of DBMS?

Answer 23

DBMS helps make data management more efficient and effective.

• Better data integration and less data inconsistency (inconsistency = Different versions of the same data appear indifferent places).
• Improved Data Sharing: end users have better access to more managed data.
• Improved Data Security: More users access the data, greater the risks of data security breaches.
• Improved Data Access
• Improved Decision Making. Important: Data Quality (accuracy, validity, and timeliness of data).

Question 24

What are the types of databases?

Answer 24

Single user supports only one user at a time.

Multiuser supports multiple users at the same time.

Workgroup databases: Supports a small number of users or a specific department.

Enterprise database: Supports many users across many departments.

Question 25

What is a General-purpose database?

Answer 25

Everyone can have access to it. Contains a wide variety of data used in multiple disciplines.

Question 26

What is a Discipline-specific database?

Answer 26

Contains data focused on specific subject areas.

Question 27

What is an Operational database?

Answer 27

Designed to support a company’s day-to-day operations.

Question 28

What is Unstructured data?

Answer 28

Data that exists in its original (raw) state, i.e., the format it was collected. The data exists in a format that does not lend itself to the processing that yields information.

Question 29

What is Structured data?

Answer 29

The result of formatting unstructured data to facilitate storage, and generation of information. Structure is applied based on type of processing to be performed.

Question 30

What is Semistructured data?

Answer 30

Data that been processed to some extent.

Question 31

What is row in databases?

Answer 31

Record

Question 32

What is column in databases?

Answer 32

Field

Question 33

What is everything in the cell in databases?

Answer 33

Data in Access

Question 34

What is Analytical database?

Answer 34

Stores historical data and business metrics used exclusively for tactical or strategic decision making

Question 35

What is Data warehouse?

Answer 35

Stores data in a format optimized for decision support

Question 36

What is Online analytical processing (OLAP)?

Answer 36

Tools for retrieving, processing, and modeling data from the data warehouse

Question 37

What can be some problems with file system data processing?

Answer 37

Lengthy development times Difficult of getting quick answers Complex administration system Lack of security and limited data sharing = everyone can have access to it Extensive programming (read, edit, write)

Question 38

What is Data dependence?

Answer 38

Data access changes when data storage characteristics change.

Question 39

What is Data independence?

Answer 39

Data storage characteristics is changed without affecting the program’s ability to access the data.

Question 40

What is Data Redundancy?

Answer 40

Having a lot of same data. The data has been duplicated/repeated many times.

Question 41

What are the problems with data redundancy?

Answer 41

Storage consuming Money consuming because you have to pay for a storage location Poor data security Data inconsistency Increased likelihood of data-entry errors when complex entries are made in different files Data anomaly: Develops when not all of the required changes in the redundant data are made successfully, for example an employee address changed, but is not corrected in all files in the database