SQL for Java Devs · interview question
Why can mapping a joined orders plus order_items result set be trickier than mapping a single products table?
Multiple choiceHardchapter-8-curatedpremiumsql-for-java-devsresultsets-and-mapping
Answer and explanation
Correct answer
D. Because join rows repeat parent columns and may need to be grouped into one object graph
Why
Joined queries often duplicate the parent columns across multiple rows. Good mapping code rebuilds the object graph intentionally instead of accidentally creating duplicate parent objects.
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