Spring 引导：全局设置 hibernate 序列

Question

Currently I define the tables the following way:

The example is in Kotlin, but you can answer in Java if you want.

@Entity
data class Task(@Id @GeneratedValue(strategy = GenerationType.SEQUENCE)
                var id: Int = 0,

                @ManyToOne(optional = false) @OnDelete(action = OnDeleteAction.CASCADE)
                var exercise: Exercise = Exercise(),

                @Column(nullable = false)
                var name: String = "")

@Entity
data class Exercise(@Id @GeneratedValue(strategy = GenerationType.SEQUENCE)
                    var id: Int = 0,

                    @Column(nullable = false)
                    var count: Int = 0)

Using this example all tables are using the same sequence: hibernate_sequence .

If I want to configure it eg setting a custom allocationSize , then I must define it in every table, am I right?

@SequenceGenerator(name = "task_seq", sequenceName = "task_seq", allocationSize = 100)

Is there a Bean or anything else? Because I like the idea of using the same sequence for all tables.

Answer 1

You can have an abstract base class with Id like:

import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.persistence.MappedSuperclass;

@MappedSuperclass
public abstract class BaseEntity {

    @Id 
    @GeneratedValue(strategy = GenerationType.SEQUENCE)
    private Long id;

    public Long getId() {
        return id;
    }

    public void setId(Long id) {
        this.id = id;
    }

}

and every entity will extend this.

Answer 2

That works but in the case of using hibernate Envers it would create two sequences.