Types of Database (Cambridge (CIE) IGCSE ICT)

Types of databases

What is a database?

• A Database is a structured, persistent collection of data

• It allows easy storage, retrieval, and management of information

• Electronic databases offer a number of key benefits:

  • Easier to add, delete, modify and update data

  • Data can be backed up and copied easier

  • Multiple users, from multiple locations, can access the same database at the same time

• There are two main types of database

  • Flat file

  • Relational

Flat file database

• A flat file database is one that stores all data in a single table

• It is simple and easy to understand but causes data redundancy, inefficient storage and is harder to maintain

• Consider this example flat file table of students 

  

  • This table has redundant data - the tutor and form room information repeats, this is inefficient

  • If a tutor changed their name we would need to find all instances of that name and change them all

  • Missing any would mean the table had inconsistent data

Relational database

• A relational database is one that organises data into multiple tables 

• It uses keys to connect related data which reduces data redundancy, makes efficient use of storage and is easier to maintain

• A relational database solves the issues in a flat file database:

  • A new table could be created to store the tutor information and the tutor information in the student table could be moved to the new table

  • Then a foreign key in the student table (TutorID) could link a student to their tutor

  

  • Now the name of each tutor and their form room is stored only once

  • This means if they change only one piece of data, the data is updated in the entire database and inconsistency is avoided

Tables & records

What is a table?

• A table is a complete set of records about the same subject/topic in a database

• An example of a database table named cars is below

cars

What is a record?

• A record is complete set of fields on a single entity in a table (row)

• An example of a record in the cars table below is highlighted in green

cars