Additional Notes
Why is joined row mapping harder than mapping one simple table?
Track: Java
Topic: SQL for Java Devs
Focus: ResultSets and Mapping
Java: ResultSets and Mapping
Answer
Join rows often repeat parent data and must be grouped back into one aggregate.
A query that joins `orders` and `order_items` might return multiple rows for one order. Good mapping code recognizes the repeated parent columns and rebuilds the intended object graph instead of duplicating the parent object.
A query that joins `orders` and `order_items` might return multiple rows for one order. Good mapping code recognizes the repeated parent columns and rebuilds the intended object graph instead of duplicating the parent object.
Topics: Java ResultSets and Mapping SQL for Java Devs