Data modelling - Concept
Data schema
The defined structure of data, including what fields exist and how they relate
What's it for?
Makes sure everyone building or using the data knows what information should exist and how it fits together.
For example…
Adding a “preferred name” field means updating the schema before the HR app can save it.
A customer table's schema says every record has a CustomerID, name, email and account status, with CustomerID linking to orders
Think of it like…
A passport with fixed places for your name, photo, date of birth and other details, each designed to hold a particular kind of information