Quiz 1.3

Question 1

1. What is the informal or general definition of a database?

Answer 1

Collection of related data (facts about the real world)

Question 2

2. Give a more formal definition of a database (include the three key implicit properties we discussed in class)?

Answer 2

• Logically Coherent.
• My database needs to have a purpose.
• Representative of the real world.

Question 3

3. What is a Database Management System (DBMS)?

Answer 3

Piece of software that helps us administrate our data.

Question 4

4. What four main actions does the Database Management System (DBMS) help us to facilitate in relation to the database (please complete the actions below as well as providing a short description)?

Answer 4

a. D – Define – data types, attribute names, entities (schema) in the database catalog (meta data).

b. C – Construct – file structures, disk, etc… how we represent our data (attributes make the majority of this).

c. M – Manipulate – Query, update, etc… on my database (modifying the state of the database). SQL – DML (Data Manipulation Language).

d. S – Need to make the database available to multiple users (multiuser vs. single user systems).

Question 5

5. What two other actions does the Database Management System (DBMS) help us facilitate in relation to the database (please complete the words below ?

Answer 5

a. P – Protection, implements RBAC (what is this?).

b. M – Maintain – apply updates to the DBMS software, indexing maintenance, etc…

Question 6

6. In the database approach, data types, constraints, and locations of the data are stored where?

Answer 6

Database Catalog (Meta data)

Question 7

7. This mechanism of storing data (see question 6) separately from the data types, constraints, and locations of the data facilitates this type of data independence or abstraction?

Answer 7

Program data independence.

Question 8

8. What are the two main properties of a transaction (give a short description of each)?

Answer 8

Isolation – as an end user, I need the system to appear as if I’m the only user.
Atomicity – shouldn’t have partial success in manipulation of my database (all pass, or all fail).

Question 9

9. What is the name for the combination of the primary database and secondary DBMS & related software?

Answer 9

The database system.

Question 10

10. The class of users who require access to the database for querying, updating, and generating reports to do their jobs?

Answer 10

End Users.

Question 11

11. Name three different types of users from the class of users described in question 10 (give a short description for each)?

Answer 11

• Casual (you know the rest)
• Naïve (Least about the database management system)
• Sophisticated (Most about the database management system)
  o DBA (Database Admin)
   Database Designer
   Software Engineer
   System Engineer, etc…
• Standalone

Question 12

12. What are three benefits of using a Database Management System (DBMS) over a file-based system?

Answer 12

Control data redundancy – each user group might have same representation of student.
- Leads to data inconsistency.
- DOE (Duplication of Effort)
Security – implement more granular access i.e., RBAC, etc…
Ensure data abstraction – i.e., program data independence, method data independence.

Question 13

13. When might you choose to use a file based-based system over a Database Management System (DBMS)?

Answer 13

Single user system, overhead cost, short timeline.

Question 14

14. What law predicts that the number of transistors on a microchip will double every two years?

Answer 14

Moore’s law

Question 15

15. Describe the difference of horizontal and vertical scalability?

Answer 15

Vertical scalability increasing the storage medium space, ram, etc.., horizontal scalability – creating more instances of my databases programs (API).

Question 16

16. The module that typically handles user interaction and provides the user-friendly interfaces such as apps for mobile devices, or forms or menu-based GUIs (graphical user interfaces) for PCs.

Answer 16

Client Module

Question 17

17. The module that typically handles data storage, access, search, and other functions.

Answer 17

Server Module

Question 18

18. What is the suppression of details of data organization and storage referred to as (in general)?

Answer 18

Data abstraction

Question 19

19. What is the collection of concepts that can be used to describe the structure of a database referred to as?

Answer 19

Data Model

Question 20

20. What are the three types of general data models (name, and give a short description for each)?

Answer 20

Conceptual
Representational
Physical

Question 21

21. What are the three general components of the Conceptual Data Model (name and give a short description for each)?

Answer 21

Entities, attributes, relationships.

Question 22

22. This is referred to as the “description of the database”, is specified during database design, and is not expected to change frequently?

Answer 22

Database Schema

Question 23

23. What is the data in a database at a particular moment in time referred to as?

Answer 23

Database snapshot, database state

Question 24

24. What is the state of the database called that corresponds to when it satisfies the structure and constraints specified in the schema?

Answer 24

Valid state, business rules (business logic) – can’t be enforced by the DBMS.

Question 25

25. Changes occasionally need to be applied to the schema as the application requirements change, this is referred to as what?

Answer 25

Schema Evolution

Question 26

26. What are the three levels of the three-schema architecture (name, and give a short description for each)?

Answer 26

External Conceptual Physical

Question 27

27. What level of the three-schema architecture is the actual data stored at?

Answer 27

Physical

Question 28

28. What is the process of transforming requests and results between levels of the three-schema architecture?

Answer 28

Mapping

Question 29

29. What is data independence (in relation to the three-schema architecture)?

Answer 29

The ability to alter one level of the schema, without having to make changes to the other.

Question 30

30. Define the two types of data independence?

Answer 30

Logical data independence – Conceptual + External Physical data independence – (Physical + (Conceptual + External)).

Question 31

31. Which type of data independence is harder to achieve and why?

Answer 31

Logical data independence – Conceptual + External

Question 32

32. The high-level DML (Data Manipulation Language) used in a standalone interactive manner is referred to as what?

Answer 32

Query language

Question 33

33. This type of language is used by the DBA and database designers to define the schema.

Answer 33

DDL (Data Definition Language)