单向关系的JPA2注释

Question

您好
在下面详述的InstrumentConfig类中，JPA2注释应该用于仪器和市场吗？

由于

@Entity
@Access(AccessType.FIELD)
class Instrument {
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    long id;

    @Basic
    String code; // EURCHF, GOOG, etc.
}

@Entity
@Access(AccessType.FIELD)
class Market {
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    long id;

    @Basic
    String name;
}

@Entity
@Access(AccessType.FIELD)
class InstrumentConfig {
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    long id;

    // what JPA2 annotations should instrument and market have?
    Instrument instrument;
    Market market;

    @Basic
    String dataURL
}

Answer 1

在最简单的情况下就是这样（外键列默认命名，没有级联等）：

@ManyToOne
Instrument instrument;     
@ManyToOne
Market market;