Hibernate – OneToOne, OneToMany, ManyToOne, ManyToMany mappings

By specifying the @JoinColumn on both models you don’t have a two way relationship. mappedby

One to One

bidirectional One to One is EAGER

@MapsId (before jpa2 – @PrimaryKeyJoinColumn)

One To Many, Many To One

Unidirectional without @JoinColumn requires additional table for joining

Bidirectional

Is it possible to limit the size of a @OneToMany collection with Hibernate or JPA Annotations? – That’s not possible. Hibernate has two options for you:

  • you load the children collection upon fetching the parent entity
  • you load the children collection lazily on first access

@Where or @Filter are more useful in this situation

or query

Composit primary key

 

Many To Many

 

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