N_plus_1_Query_Problem

N+1 Query Problem

• when an ORM, like hibernate, executes 1 query to retrieve the parent entity and N queries to retrieve the child entities.
• Example, we have users table and address table for each user
• In essence, this happens when we have @OneToMany() or similar relationship on ORM
• For Spring JPA, see JPA N+1 Query Problem Solution
• reference:
  • https://stackoverflow.com/questions/97197/what-is-the-n1-selects-problem-in-orm-object-relational-mapping
  • https://www.baeldung.com/spring-hibernate-n1-problem