Why You Should Avoid Unidirectional @OneToMany And Prefer Bidirectional @OneToMany Relationship

Description: As a rule of thumb, unidirectional @OneToMany association is less efficient than the bidirectional @OneToMany or the unidirectional @ManyToOne associations. This application is a sample that exposes the DML statements generated for reads, writes and removal operations when the unidirectional @OneToMany mapping is used.

Key points:

• regular unidirectional @OneToMany is less efficient than bidirectional @OneToMany association
• using @OrderColumn come with some optimizations for removal operations but is still less efficient than bidirectional @OneToMany association
• using @JoinColumn eliminates the junction table but is still less efficient than bidirectional @OneToMany association
• using Set instead of List or bidirectional @OneToMany with @JoinColumn relationship (e.g., @ManyToOne @JoinColumn(name = "author_id", updatable = false, insertable = false)) still performs worse than bidirectional @OneToMany association

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