在创建 JPA 实体之间的关系时出错

Question

我正在尝试创建实体，但出现以下错误。

Internal Exception: Exception [EclipseLink-7157] (Eclipse Persistence Services - 2.5.2.v20140319-9ad6abd): org.eclipse.persistence.exceptions.ValidationException
Exception Description: Entity class [class application.Team] must use a @JoinColumn instead of @Column to map its relationship attribute [mPlayers].

这些是我的实体，我需要使用 Java Persistence API (JPA) 将数据存储到数据库中。为此，我创建了如下实体。也许我以错误的方式创建了实体之间的关系。

人

@MappedSuperclass
public class Person {
 @Id
 @GeneratedValue( strategy= GenerationType.AUTO )
 protected int p_id;

 protected String firstName;
 protected String middleName;
 protected String lastName;
 protected String phone; 
 protected String email;

 public Person() {
 }
}

玩家

    @Entity
@Table( name = "tbl_players")
@AttributeOverride(name="id", column=@Column(name="player_id"))
public class Player extends Person implements Serializable{
    private int player_id;

    @Column(name = "goals_in_year")
    private int numberOfGoalsInCurrentYear;

    private boolean goalie;

    @Column(name = "defended_goals")
    private int defendedGoals;

    public Player(){

    }
 }

经理

@Entity
@Table( name = "tbl_manager")
@AttributeOverride(name="id", column=@Column(name="manager_id"))
public class Manager extends Person implements Serializable{
    private String dob;
    private int starRating;

    @OneToOne
    private Team teamToManage;

    public Manager(){
    }
}

团队

@Entity
@Table( name = "tbl_team")
public class Team implements Serializable {
    @Column(name = "team_name")
    @Id
    String teamName;

    @OneToOne
    Manager manager;

    @Column(name = "team_players")
    @OneToMany
    private List<Player> mPlayers = new ArrayList<>();

    @Column(name = "jersey_color")
    String jerseyColor;

    public Team(){
    }
}

联赛

@Entity
public class League {
    @Id
    private int league_id;

    @OneToMany
    @Column(name = "League Teams")
    private List<Team> mTeam = new ArrayList<>();

    public void addTeam(Team team) {
        mTeam.add(team);
    }

    public void removeTeam(Team team) {
        mTeam.remove(team);
    }
}

Answer 1

这似乎是由于@Column(name = "team_players") 和@OneToManyPlease

请阅读link

Answer 2

使用@JoinColumn 代替@Column 进行映射（@OneToMany、@ManyToMany、@ManyToOne）。 @Column 用于指定持久化属性或字段的映射列。

Answer 3

为什么不将每个模型 class 视为一个实体，然后使用 ManyToOne 或 OneToMany

加入模型

Answer 4

玩家

@Entity
@Table( name = "tbl_players")
@AttributeOverride(name="id", column=@Column(name="player_id"))
public class Player extends Person implements Serializable{
    private int player_id;

    @Column(name = "goals_in_year")
    private int numberOfGoalsInCurrentYear;

    private boolean goalie;

    @Column(name = "defended_goals")
    private int defendedGoals;

    @OneToOne // or @OneToMany as you desire
    @JoinColumn(name="team_name") // here the name you have given to the column in tbl_players
    private Team team;

    public Player(){

    }
 }

经理

@Entity
@Table( name = "tbl_manager")
@AttributeOverride(name="id", column=@Column(name="manager_id"))
public class Manager extends Person implements Serializable{
    private String dob;
    private int starRating;

    @OneToOne(mappedBy="manager")
    private Team teamToManage;

    public Manager(){
    }
}

团队

@Entity
@Table( name = "tbl_team")
public class Team implements Serializable {

    @Id
    @Column(name = "team_id")
    private int id;    

    @Column(name = "team_name")
    String teamName;

    @OneToOne
    @JoinColumn(name="manager_id")
    Manager manager;

    @Column(name = "team_players")
    @OneToMany(mappedBy="team")
    private List<Player> mPlayers = new ArrayList<>();

    @Column(name = "jersey_color")
    String jerseyColor;

    @ManyToOne(mappedBy="")
    private League league;

    public Team(){
    }
}

联赛

@Entity
@Table( name = "tbl_league")
public class League {

    @Id
    @Column(name="league_id")
    private int league_id;

    @OneToMany
    @JoinTable(name="tbl_league_teams",joinColumns=@JoinColumn(name = "league_id"), inverseJoinColumns=@JoinColumn(name = "team_id"))
    private List<Team> mTeam = new ArrayList<>();

    public void addTeam(Team team) {
        mTeam.add(team);
    }

    public void removeTeam(Team team) {
        mTeam.remove(team);
    }
}

创建名为 tbl_league_teams 的新中间映射 table，包含列 league_id 和 team_id 以便于映射 League 实体中的 @JoinTable联赛中的球队之间。

在创建 JPA 实体之间的关系时出错

getting error during the creation of relationship between JPA entities

java

database

entities

jpa-2.1