Databases

Question 1

What is a Relational Database

Answer 1

A database which recognises the difference between entities and uses different tables for each entity

Question 2

What is an entity

Answer 2

An item of interest about which information is stored

Question 3

What is a flat file?

Answer 3

A database that consists of a single file, usually about one entity

Question 4

What is a primary key

Answer 4

A unique identifier for each record in a table

Question 5

What is a foreign key

Answer 5

The attribute which links two tables together

Question 6

What is a secondary key

Answer 6

An index other than the primary key used to search and sort through the database with more convenience and speed

Question 7

What is normalisation

Answer 7

This is the process of coming up with the
best layout for a relational database

Question 8

What does normalisation try to accomplish

Answer 8

● No redundancy (unnecessary duplicates)
● Consistent data throughout linked tables
● Records can be added and removed without issues
● Complex queries can be carried out

Question 9

What is an index

Answer 9

An index is a data structure used to look
up and access data in database quickly

Question 10

What does capturing data mean

Answer 10

Capturing data is the process of getting the information you wish to use

Question 11

What does selecting data mean

Answer 11

Selecting data is the process of reducing excess information to obtain only the data you require

Question 12

What does managing the data mean

Answer 12

Managing the data means to manipulate the information in any type of way such as through sorting through it or selecting certain parts using SQL

Question 13

What is the most common language used to manipulate data in databases

Answer 13

SQL

Question 14

What are the requirements to be in first normal form

Answer 14

• Contain atomic values
• Have no repeating groups
• Have unique column names
• Have a unique identifier (primary key)

Question 15

What are the requirements to be in second normal form

Answer 15

• The database is in first normal form,
• There are no partial dependencies (no
  composite keys)

Question 16

What are the requirements to be in third normal form?

Answer 16

• The database is in second normal form.
• There are no non-key dependencies

Question 17

What does SQL stand for?

Answer 17

Structured Query Language

Question 18

What is SQL

Answer 18

A declarative language used to manipulate databases

Question 19

What is referential integrity

Answer 19

The process of ensuring consistency as it makes sure that information is not removed if it is required elsewhere in a linked database

Question 20

What is a transaction defined as

Answer 20

A transaction is a single operation executed on data

Question 21

What does ACID stand for

Answer 21

Atomicity, Consistency, Isolation, Durability

Question 22

What does Atomicity (in ACID) mean

Answer 22

A transaction must be processed in its entirety or not at all

Question 23

What does consistency (in ACID) mean?

Answer 23

A transaction must maintain referential integrity rules between linked tables.

Question 24

What does isolation (in ACID) mean?

Answer 24

Simultaneous execution of transactions should lead to the same result as if they were executed one after the other

Question 25

What does durability (in ACID) mean?

Answer 25

Once a transaction has been executed it will remain so regardless of the circumstances

Question 26

What is record locking

Answer 26

Record locking is the process of preventing simultaneous access to a record.

Question 27

What is the name of an issue that can arise as a result of record locking

Answer 27

Deadlock

Question 28

What is redundancy

Answer 28

The process of creating more than one copy of data in a physically different location