Relational vs Non-Relational Databases on Azure: Complete DP-900 Guide

Tables, Rows, and Columns

The fundamental structure of relational data. A table represents an entity (Customers, Orders, Products). Each row is one instance. Each column is one attribute.

Exam tip: "Entity" in modeling becomes "table" in the database. "Attribute" becomes "column." "Instance" becomes "row/record."

Primary Keys and Foreign Keys

A primary key uniquely identifies each row in a table (e.g., CustomerID). A foreign key in one table references the primary key of another table to create a relationship (e.g., Orders.CustomerID references Customers.CustomerID).

Exam tip: Know that foreign keys enforce referential integrity — you cannot insert an order for a CustomerID that doesn't exist in the Customers table.

Normalization

The process of organizing tables to reduce data redundancy. Normalization splits data across multiple related tables rather than storing it all in one flat table.

Exam tip: DP-900 tests the concept of normalization but not the specific normal forms (1NF, 2NF, 3NF) in depth. Know that normalization reduces duplication and improves consistency.

SQL: SELECT, INSERT, UPDATE, DELETE

The four core DML (Data Manipulation Language) statements. The exam may show basic SQL syntax. Know: SELECT retrieves data, INSERT adds rows, UPDATE modifies rows, DELETE removes rows.

DDL (Data Definition Language) statements: CREATE TABLE, ALTER TABLE, DROP TABLE — these define the schema structure.

Exam tip: Know DDL vs DML. DDL modifies structure; DML modifies data.

Database Objects: Views, Indexes, Stored Procedures