Relational Databases 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.
Is the primary key automatically indexed?
Yes.
What does capturing data mean?
Capturing data is the process of getting the information you wish to use.
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 is the most common language used to manipulate data in databases?
SQL.
