What does deferred execution mean in LINQ?
PICTURE THIS: 1, 2, 2, 8
Simple meaning
The query runs when you enumerate, not when you build it.
WHY — LINQ instead of guessing?
Why interviewers care about LINQ:
who only read docs from people who shipped.
and tied to .NET work.
Name the idea, why it exists, then one short example.
End with when you use it and one common pitfall.
STEPS — What happens step by step?
Before you speak the answer, walk the interviewer through these steps:
- 1The query runs when
you enumerate, not when you build it.
- 2Multiple enumerations may hit
the database again.
- 3I materialize with ToList
when needed once.
- 4Give an example
One tiny concrete case you can say aloud.
- 5Common mistake
What juniors usually get wrong.
- 6Close
When you pick this over the alternative.
EXAMPLE — See it in action
Here's a short line you can speak, broken into clear beats:
Note: Adapt this scaffold to your own project — keep it under 60–90 seconds.
Key takeaway
The query runs when you enumerate, not when you build it. Multiple enumerations may hit the database again.