无法删除父实体，因为在双向映射情况下有子引用

Question

1. 父级不拥有colum，因此映射由“mappedby”配置
2. 子项有一个复合键，其中一个列通过其ID链接到父项
3. 配置由JPA注释完成

当hibernate执行它的查询时，它不能发现有一些子级对试图删除的记录有外键约束，所以它希望执行“父级先删除”，然后移动到“子级”。

起因是：

null

• 可选=false
• name=表列的名称

import javax.persistence.CascadeType;
import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.FetchType;
import javax.persistence.Id;
import javax.persistence.OneToMany;
import java.util.Objects;
import java.util.Set;

@Entity
public class Parent {
    @Id
    @Column
    private long id;

    @Column
    private String name;

    @OneToMany(mappedBy = "parent",
            fetch = FetchType.EAGER,
            cascade = CascadeType.ALL,
            orphanRemoval = true)
    private Set<Child> children;

    public long getId() {
        return id;
    }

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

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public Set<Child> getChildren() {
        return children;
    }

    public void setChildren(Set<Child> children) {
        this.children = children;
    }

    @Override
    public boolean equals(Object o) {
        if (this == o) return true;
        if (o == null || getClass() != o.getClass()) return false;
        Parent parent = (Parent) o;
        return id == parent.id;
    }

    @Override
    public int hashCode() {
        return Objects.hash(id);
    }
}

import javax.persistence.CascadeType;
import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.Id;
import javax.persistence.IdClass;
import javax.persistence.JoinColumn;
import javax.persistence.ManyToOne;
import java.util.Objects;

@Entity
@IdClass(ChildIdentifier.class)
public class Child {
    @Id
    @Column
    private long id;

    @Column
    private String name;

    @Id
    @JoinColumn(nullable = false,
            name ="parent_id",
            referencedColumnName = "id")
    @ManyToOne(optional = false)
    private Parent parent;

    public long getId() {
        return id;
    }

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

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public Parent getParent() {
        return parent;
    }

    public void setParent(Parent parent) {
        this.parent = parent;
    }

    @Override
    public boolean equals(Object o) {
        if (this == o) return true;
        if (o == null || getClass() != o.getClass()) return false;
        Child child = (Child) o;
        return id == child.id &&
                Objects.equals(parent, child.parent);
    }

    @Override
    public int hashCode() {
        return Objects.hash(id, parent);
    }
}

import javax.persistence.CascadeType;
import javax.persistence.Column;
import javax.persistence.Id;
import javax.persistence.JoinColumn;
import javax.persistence.ManyToOne;
import java.io.Serializable;
import java.util.Objects;

public class ChildIdentifier implements Serializable {
    @Id
    @Column
    private long id;
    @JoinColumn(nullable = false,
            name ="parent_id",
            referencedColumnName = "id")
    @ManyToOne(optional = false)
    private Parent parent;

    @Override
    public boolean equals(Object o) {
        if (this == o) return true;
        if (o == null || getClass() != o.getClass()) return false;
        ChildIdentifier that = (ChildIdentifier) o;
        return id == that.id &&
                Objects.equals(parent, that.parent);
    }

    @Override
    public int hashCode() {
        return Objects.hash(id, parent);
    }

    public long getId() {
        return id;
    }

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

    public Parent getParent() {
        return parent;
    }

    public void setParent(Parent parent) {
        this.parent = parent;
    }
}

Answer 1

我想通了问题。删除不是通过实体管理器的remove功能完成的。

执行delete操作的存储库由@Query注释实现（示例@Query（“delete from parent where id=:id”））。我还没有完全理解这种行为背后的原因，但JPQL没有导致正确的订单删除。

要解决此问题：

null