PL-300 Model the data Practice Question
You are building a Power BI semantic model that includes a Customers table and a Sales table. The Customers table has a unique CustomerID column. The Sales table has a CustomerID column that references the Customers table. You need to create a relationship between the two tables. Which type of relationship should you create?
⚠ Common exam trap
Many exam-takers confuse the direction of the relationship or assuming a many-to-many relationship is needed when unique keys exist.
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
One-to-many relationship with Customers as the one side and Sales as the many side.
The correct relationship is one-to-many from Customers to Sales because each customer is unique in the Customers table and can have multiple related rows in the Sales table. This is the standard dimension-to-fact relationship in a star schema, enabling efficient filtering and aggregation.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Many-to-many relationship between Customers and Sales.
Why it's wrong here
A many-to-many relationship is unnecessary here because each customer has a unique CustomerID in the Customers table. Many-to-many relationships are used when both tables have duplicate keys, which is not the case. Using many-to-many would complicate the model and could lead to incorrect results or performance issues.
- ✓
One-to-many relationship with Customers as the one side and Sales as the many side.
Why this is correct
This is the correct relationship because each customer appears once in the Customers table but can have multiple sales transactions in the Sales table. A one-to-many relationship from Customers to Sales ensures that filtering on Customers propagates to Sales, which is typical for a dimension-to-fact relationship in a star schema.
- ✗
One-to-one relationship between Customers and Sales.
Why it's wrong here
A one-to-one relationship implies that each customer has exactly one sale and each sale belongs to exactly one customer. However, a customer can have multiple sales, so this relationship type would not be valid and would cause errors when multiple sales exist for a single customer.
- ✗
Many-to-one relationship with Sales as the one side and Customers as the many side.
Why it's wrong here
This reverses the cardinality. In a typical star schema, the dimension (Customers) is on the one side and the fact (Sales) is on the many side. Placing Sales on the one side would be incorrect because a single sale cannot be associated with multiple customers, and it would not reflect the actual data relationships.
About these practice questions
Courseiva writes every PL-300 question from scratch — 524 in total, each with an explanation and a wrong-answer breakdown. None are copied from real exams or dumps. Learn why practice questions differ from exam dumps →
JA
Written and reviewed by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
Last reviewed September 2026 · checked against the official Microsoft exam blueprint
This PL-300 practice question is part of Courseiva's free Microsoft certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the PL-300 exam.