1.3.2 Databases

Question 1

1.3.2 A)
What is a database

Answer 1

organised collection of data. That allows for easy adding, modifying, deletion and searching of the data.

Question 2

1.3.2 A)
Inside a database a table is also known as
Inside a table a row is also known as
Inside a table a column is also known as

Answer 2

1) an entity or file
2) a row or tuple
3) a field or attribute

Question 3

1.3.2 A)
What is the advantages and disadvantages of a flat file

Answer 3

A) simple and quick to set up, do not need a specialised to maintain, good for storing small amount of data
D) When lots of data inputted likely to have repeating data which is inefficient as it takes up unnecessary space, it becomes slow to query and is difficult to maintain.

Question 3

1.3.2 A)
What is a flat file

Answer 3

single file, with comma separated values (csv)

Question 4

1.3.2 A)
What is a relational data base

Answer 4

Splits information into multiple tables. links tables with one another using relationships for 1:M , M:M , 1:1.

Question 5

1.3.2 A)
What is the advantages and disadvantages of a relational data base

Answer 5

A) structured and efficient way to store and retrieve data , reduce redundancy.
D) Expert needed , costs , performance

Question 6

1.3.2 A)
What is a primary key

Answer 6

A field that has a unique value / a
unique identifier (1) for every record in
that table (1)

Question 7

1.3.2 A)
What is a foreign key

Answer 7

attribute that links to tables together, foreign key has to be a primary key in another table

Question 8

1.3.2 A)
What is a composite key

Answer 8

candidate key that consists of two or more attributes that together create a unique identifier. values of comp key must be diff across all records

Question 9

1.3.2 A)
What is a secondary key

Answer 9

Can also specify one or more secondary keys to be indexed. Helped files be searched quickly and easily (instead of typing a unique id something easy to remember like a last name )

Question 10

1.3.2 A)
What is indexing

Answer 10

Held for primary keys so it can be easily located quickly. so that sequential searching is not needed.

Question 11

1.3.2 A)
What is normalisation ? ( in terms of data bases )

Answer 11

Process of coming up with the best possible layout for relational databases.

Question 12

1.3.2 A)
Properties of normalisation in terms of databases

Answer 12

no redundancy
consistent data in linked tables
easy to add / remove records

Question 13

1.3.2 C)
What is first normal form

Answer 13

• No Repeating fields/data
• Data is atomic
• Has a primary Key

Question 14

1.3.2 C)
What is second normal form

Answer 14

• Is in First Normal Form
• Every field is dependent on the
  primary key

Question 15

1.3.2 C)
What is third normal form

Answer 15

Has a transitive relationship/ A non-key field depends on another non-key field