Week_1-3

Question 1

Name a few points about Flat File System.

Answer 1

Ordinary Operating system files.
Contain no information to communicate the file structure or any relationship between files. 
No physical data independence
Data redundancy
No data intergrity

Question 2

What does a database require?

Answer 2

Data
Hardware that physically stores the data.
Software that manages the hardware to store data.
Users.

Question 3

Name a few points about The Relational Model.

Answer 3

Flexible
Ideal for “ad hoc” queries
Relates records as they are needed, using their data alone.
Foreign data keys are used instead of pointers.
Examples: ORACLE, MySQL, SQL Server.

Question 4

Rules of Relational Tables:

Answer 4

Ordering of rows is not significant.
Ordering of columns is not significant
A cell contains only one value
No duplicate rows.

Question 5

What is a composite key?

Answer 5

A primary key that can be composed of more than one attribute.