Planned lessonJNR-030-L01

Many-to-one: the default relationship

On This Lesson 4 topics

This lesson is planned. The outline below lists the topics it will cover. The full lesson has not been published yet.

In this lesson

map the most common relationship correctly.

Many Products belong to one Category: @ManyToOne on the product.
The table holding the foreign key is the "many" side (product.category_id).
@JoinColumn names the foreign key column.
Use fetch = FetchType.LAZY; the default for @ManyToOne is EAGER, which often causes extra queries.
Start here; most designs need only this plus a query.

Draft outline details

java

@ManyToOne(fetch = FetchType.LAZY, optional = false)
@JoinColumn(name = "category_id")
private Category category;

Which table holds the foreign key in a many-to-one?

Show answer

The "many" side.

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