DP-900Domain 2: Identify Considerations for Relational Data on AzureRelational Data on AzureeasySingle choice
In an Orders table, a CustomerID column links each order to a row in the Customers table. What is CustomerID called in the ORDERS table?
A.Primary key
PK uniquely identifies the row's own table.
B.Foreign key
Reference to another table's PK = FK. Correct.
C.Composite key
Composite = multi-column key — different concept.
D.Index
An index speeds lookups — doesn't define relationships.
Why this answer
A foreign key references a primary key in ANOTHER table — enforcing referential integrity (you can't order for a nonexistent customer). The primary key is in Customers; Orders.CustomerID is the FK.
Correct answer: B · Last reviewed 2026-11-05
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Answer without seeing the solution first in the Relational Data on Azure practice session.
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