Database Concepts

Question 1

What is a database?

Answer 1

A database is a collection of related data.

Question 2

What does data refer to in the context of a database?

Answer 2

Data refers to known facts that can be recorded and have implicit meaning.

Question 3

What is the miniworld or universe of discourse (UoD)?

Answer 3

The miniworld or UoD represents some aspect of the real world that a database reflects.

Question 4

What is a database management system (DBMS)?

Answer 4

A DBMS is a collection of programs that enables users to create and maintain a database.

Question 5

What is meta-data in the context of a database?

Answer 5

Meta-data is the descriptive information stored in the database, including structure and constraints.

Question 6

What are the main functions of a DBMS?

Answer 6

The main functions include defining, constructing, manipulating, and sharing databases.

Question 7

What is the purpose of protecting a database?

Answer 7

Protection includes safeguarding against hardware/software malfunctions and unauthorized access.

Question 8

What example is provided for a database in the text?

Answer 8

A UNIVERSITY database for maintaining information concerning students, courses, and grades.

Question 9

What distinguishes the database approach from the traditional file processing approach?

Answer 9

The database approach maintains a single repository of data defined once, accessed by various users.

Question 10

What does self-describing nature of a database system mean?

Answer 10

It means the database system contains a complete definition of the database structure and constraints.

Question 11

What is program-data independence?

Answer 11

Program-data independence means that changes to a file’s structure do not require changes to access programs.

Question 12

Fill in the blank: A database typically supports _______ of the data.

Answer 12

multiple views

Question 13

What is the significance of concurrency control in a multiuser DBMS?

Answer 13

It ensures that multiple users can update the same data in a controlled manner.

Question 14

When did E.F. Codd propose the relational model for databases?

Answer 14

1970-72.

Question 15

What are the two main prototypes for relational systems developed during 1974-77?

Answer 15

• Ingres
• System R

Question 16

What is the Entity-Relationship (ER) model?

Answer 16

The ER model is a conceptual data model proposed by P. Chen for database design.

Question 17

What became the ‘intergalactic standard’ for databases in the mid-1980s?

Answer 17

SQL (Structured Query Language).

Question 18

What characterized the early 1990s in the database industry?

Answer 18

An industry shakeout with fewer companies offering increasingly complex products.

Question 19

What was a major trend in the late 1990s regarding databases?

Answer 19

The rise of the Internet and the need for remote access to legacy data.

Question 20

What are OLTP and OLAP?

Answer 20

OLTP is Online Transaction Processing and OLAP is Online Analytical Processing.

Question 21

What are current trends in database technology?

Answer 21

• Data mining
• Data warehousing
• Smart/personalized shopping
• Mobile database use

Question 22

True or False: SQL successors have been widely standardized and successful.

Answer 22

False.

Question 23

What is a major threat to high-cost legacy systems like Oracle and DB2?

Answer 23

Linux with Apache supporting MySQL or Oracle on cheap hardware.

Question 24

What is the current trend in database technology mentioned in the text?

Answer 24

Mobile database use is coming to market in various ways.

Question 25

What is becoming the norm for business planning in many arenas?

Answer 25

Distributed transaction processing.

Question 26

What threat do low-cost systems pose to high-cost legacy systems?

Answer 26

Linux with Apache supporting mySQL or Oracle.

Question 27

What is the Object Oriented Everything concept related to?

Answer 27

It includes databases and is on the verge of sweeping everything before it.

Question 28

What does the term 'data abstraction' refer to?

Answer 28

Suppression of details of data organisation and storage.

Question 29

What is a data model?

Answer 29

A collection of concepts that can describe the structure of a database.

Question 30

What are the main categories of data models?

Answer 30

High-level, low-level, and representational data models.

Question 31

What do conceptual data models use to describe data?

Answer 31

Entities, attributes, and relationships.

Question 32

What is the definition of a database schema?

Answer 32

The description of a database specified during design.

Question 33

What is a schema diagram?

Answer 33

A displayed schema showing the structure of each record type.

Question 34

What is the difference between a database state and a schema?

Answer 34

A database state is the actual data at a moment in time; a schema is the structure.

Question 35

What is the term for the actual data in a database at a given time?

Answer 35

Database state or snapshot.

Question 36

What is the purpose of the DBMS catalog?

Answer 36

To store descriptions of schema constructs and constraints.

Question 37

What are the three levels of the three-schema architecture?

Answer 37

* Internal level * Conceptual level * External or view level

Question 38

What does the internal schema describe?

Answer 38

The physical storage structure of the database.

Question 39

What does the conceptual schema focus on?

Answer 39

Describing entities, data types, relationships, user operations, and constraints.

Question 40

What is an external schema?

Answer 40

It describes the part of the database that a particular user group is interested in.

Question 41

What are mappings in the context of the three-schema architecture?

Answer 41

The process of transforming requests and results between levels.

Question 42

Fill in the blank: A _______ represents a real-world object or concept in a database.

Answer 42

Entity

Question 43

True or False: The schema is sometimes called the extension of the database.

Answer 43

False

Question 44

Fill in the blank: The actual data in the database at a particular moment is called a _______.

Answer 44

Database state

Question 45

What is an attribute in the context of data models?

Answer 45

A property of interest that describes an entity.

Question 46

What ethical issues are raised regarding database use?

Answer 46

* Consulting medical records of employees * Screening partners for genetic diseases * Tracking purchasing habits * National database of convicted criminals