DP-900 · 1 Describe core data concepts
Structured data
Exam objective: Describe the features of structured data
Structured data follows a fixed schema, so every record has the same fields. It is usually shown as tables of rows and columns.
Structured data has a schema that is fixed up front. Every record carries the same fields, and you know those fields before the first record is written.
The usual shape is a table. Each row is one instance of an entity, such as one customer. Each column is one attribute of that entity, such as the city.
| CustomerID | Name | City |
|---|---|---|
| 1 | Ana Costa | Lisbon |
| 2 | Li Wei | Leeds |
Tables can point to each other through key values. An order row stores the CustomerID of the customer who placed it, instead of repeating the customer details. Data organized this way is called relational.
On the exam, look for the words fixed schema, tabular, rows and columns or the same fields for every record.
Key points
- A fixed schema means every record has the same set of fields.
- The usual shape is tabular: a row is one instance of an entity, a column is one attribute.
- Tables can reference each other through key values. That is the relational model.
- Empty values do not change the schema. A column that is mostly empty is still a column.
Exam trap
Structured does not mean "stored in a database". What counts is the fixed schema. A delimited text file with the same columns on every line holds structured data too.
Check yourself
What does it mean when data adheres to a fixed schema?
Go deeper on Microsoft Learn
- Identify data formats (Explore core data concepts)
- Explore file storage (Explore core data concepts)
Checked against Microsoft Learn on October 1, 2026.