Databases | Notion

Q0 – What is a Database?

A database is a structured collection of data that allows people to extract information in a way that meets their needs. The data can include text, numbers, pictures – anything that can be stored in a computer.

Q1 – Why Do Databases Prevent Problems?

Databases prevent problems because:

changes or additions only need to be made once → data is consistent;
the same data is used by everyone;
data is only stored once in relational databases → no data duplication.

Q2 – What Are Databases Used For?

Category	Examples
People	Patients in a hospital; pupils at a school
Things	Cars to be sold; books in a library
Events	Hotel bookings (prenotazioni); results of races

Q3 – How Is Data Stored?

Databases store data in tables:

Element	Description
Field (column)	A category of data; each field has a specific data type (e.g. `numberOfStaff` → integer / numero intero)
Record (row)	Stores details about a specific item using the fields
Primary key	A field that uniquely identifies any record in the table; only one per table

Q4 – Types of Databases

Non-Relational Databases

Do not store data in tables;
Use whatever format best suits the type of data;