如何只删除多对多关系中的关系？

Question

I have the following three tables:

player (id, name)
status (id, status_text)
player_status (player_id, status_id)

The player_status table combines the first two tables with a n-to-n relationship

Table " player ":

id	player
agzua76t34gusad	"Anna"
sdahb433tbjsdbv	"Julia"

Table " status ":

id	status_text
jjbsdnv8677v6df	"operational"
bulsiu783fdszjh	"violated"

Table " player_status "

record_id	record_status_id
agzua76t34gusad	jjbsdnv8677v6df
sdahb433tbjsdbv	bulsiu783fdszjh

The player can have a status assigned or not. Now when a player has a status, how can I remove this status, so that the player but also the status stays in the tables but only the relation in the player_status table will be removed.

These are the classes for Player and Status

@Entity
@Table(name = "player")
public class Player {

    @Column(nullable = false)
    private String id;

    @Column(nullable = false)
    private String name;

    @ManyToMany(fetch = FetchType.LAZY,
        cascade = {
            CascadeType.PERSIST,
            CascadeType.MERGE
        })
    @JoinTable(name = "player_status",
        joinColumns = {@JoinColumn(name = "player_id", referencedColumnName = "id")},
        inverseJoinColumns = {@JoinColumn(name = "status_id", referencedColumnName = "id")})
    private Set<Status> statusList = new HashSet<>();
}


@Entity
@Table(name = "status")
public class Status {

    @Column(nullable = false)
    private String id;

    @Column(name = "status_text", nullable = false)
    private String statusText;

    @ManyToMany(fetch = FetchType.LAZY,
        cascade = {
            CascadeType.PERSIST,
            CascadeType.MERGE
        }, mappedBy = "statusList")
    @JsonIgnore
    private Set<Player> players = new HashSet<>();
}

This is how the relation table is created in *.sql :

create table player_status
(
    player_id varchar references player (id) on update cascade on delete cascade,
    status_id varchar references status (id) on update cascade
);

How can I delete only an entry from the player_status table? I tried to retrieve a player from the db, changed/removed his status, but this did not update the player.

Answer 1

You just remove the associated Status from the statusList collection, and the row of the association table will be automatically deleted when the EntityManager is flushed.