Design Patterns · Junior · Question 65 of 75

What's the difference between "is-a" and "has-a" relationships?

✓Correct answer: "Is-a" suggests inheritance (a Dog is an Animal); "has-a" suggests composition (a Car has an Engine)
2They're the same
3"Has-a" always means a database relation

Explanation

If the relationship is really "has-a" or "uses-a", inheritance creates unnecessary coupling.

Further reading

Wikipedia: Composition over inheritance ↗

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