DP-900Domain 2: Identify Considerations for Relational Data on AzureRelational Data on AzuremediumSingle choice
Queries filtering on a non-keyed Email column are slow — full table scans on millions of rows. What's the standard relational fix?
A.Create an index on Email
Index on the filter column = seek not scan. Correct.
B.Normalize the table further
Normalization fixes redundancy — not lookup speed.
C.Add a foreign key
FKs enforce integrity — not query performance.
D.Move the column to another table
Moving the column doesn't change scan behavior.
Why this answer
An index on the filtered column lets the engine seek directly instead of scanning every row — the classic relational query-tuning answer. Trade-off: indexes cost write performance and storage.
Correct answer: A · Last reviewed 2026-11-05
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