Data Bases Flashcards
What is a Relational Database?
A database which recognises the
difference between entities and uses
different tables for each entity.
What is an entity?
An item of interest about which
information is stored.
What is a flat file?
A database that consists of a single file,
usually about one entity.
What is a primary key?
A unique identifier for each record in a
table.
What is a foreign key?
The attribute which links two tables
together.
What is a secondary key?
An index other than the primary key used
to search and sort through the database
with more convenience and speed.
What is normalisation?
This is the process of coming up with the
best layout for a relational database.
What does normalisation try to accomplish?
● No redundancy (unnecessary duplicates)
● Consistent data throughout linked tables.
● Records can be added and removed without issues.
● Complex queries can be carried out.
What is an index?
An index is a data structure used to look
up and access data in the database quickly.
What does capturing data mean?
Capturing data is the process of getting
the information you wish to use.
Is the primary key automatically indexed?
Yes
What method do banks use to capture data from
cheques?
They use Magnetic Ink Character
Recognition (MICR) to get all the details
apart from the amount which must be
entered manually
What does selecting data mean?
Selecting data is the process of reducing
excess information to obtain only the
data you require.
What does managing the data mean?
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.
What are the requirements to be in second normal
form?
- The database is in first normal form,
- There are no partial dependencies (no
composite keys)
