@Index annotation leads to "This annotation is not applicable to target 'member property w-CodePudding

I am trying to create an index on a foreign key using the @Index annotation. Unfortunately, the compiler complains with the following message:

This annotation is not applicable to target 'member property with backing field'

What am I doing wrong here?

@Entity
@Table(name = "my_entity")
class MyEntity(someValue: Long) : BaseEntity(someValue) {

    // .. some fields
    
    @OneToOne
    @JoinColumn(name = "another_entity")
    @Index(name = "ix_another_entity")
    var anotherEntity: AnotherEntity? = null
}

CodePudding user response：

The @Index cannot be used like this (neither in java nor in kotlin), instead you can use it e.g. as part of the @Table annotation:

@Table(name= "my_entity", indexes = [ Index(columnList = "another_entity") ])

Specifying an Index (Non-Unique Key) Using JPA

(note that e.g. MySQL auto creates an index for foreign keys: Does MySQL index foreign key columns automatically? )