https://devops-monk.com/tags/relationships/Recent content in Relationships on Devops MonkHugoen-usSun, 03 May 2026 00:00:00 +0000https://devops-monk.com/tutorials/spring-boot/spring-data-jpa-relationships/Sun, 03 May 2026 00:00:00 +0000https://devops-monk.com/tutorials/spring-boot/spring-data-jpa-relationships/Relationships are the trickiest part of JPA. A wrong cascade type or a missing mappedBy causes subtle bugs that appear in production. This article covers every relationship type with real examples and the pitfalls to avoid. Relationship Fundamentals JPA relationships can be: Direction: Unidirectional (one side knows about the other) or Bidirectional (both sides know each other) Cardinality: @OneToOne, @OneToMany, @ManyToOne, @ManyToMany Fetch: LAZY (load on access) or EAGER (load immediately) Ownership: The side with the foreign key column is the owner Default fetch types: