Hibernate复合键id生成器

Question

我有我的实体如下.我的数据模型在下面执行,我无法更改参照迭代.所以我坚持使用复合键.我想为orderId自动生成/使用一些生成器

是的我已在下面阅读. http://docs.jboss.org/hibernate/annotations/3.5/reference/en/html_single/#entity-mapping-identifier

我不想管理id生成过程,因为上面建议应用程序生成orderId.

如何使部分id生成器工作..我的选择是什么...将非常感谢专家的一些想法.

@Entity
@Table(name = "Orders", uniqueConstraints = @UniqueConstraint(columnNames = {"partner_ID", "order_ident" }))
public class Order  {

private OrderId id;

public Order() {
}


@EmbeddedId
@AttributeOverrides({
        @AttributeOverride(name = "partnerId", column = @Column(name = "partner_ID", nullable = false)),
        @AttributeOverride(name = "employeeId", column = @Column(name = "employee_ID", nullable = false)),
        @AttributeOverride(name = "orderId", column = @Column(name = "order_ID", nullable = false)) })
public OrderId getId() {
    return this.id;
}

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


}


@Embeddable
public class OrderId extends FactObject {

private int partnerId;
private int employeeId;
private int orderId;

public OrderId() {
}

public OrderId(int partnerId, int employeeId, int orderId) {
    this.partnerId = partnerId;
    this.employeeId = employeeId;
    this.orderId = orderId;
}

@Column(name = "partner_ID", nullable = false)
public int getpartnerId() {
    return this.partnerId;
}

public void setpartnerId(int partnerId) {
    this.partnerId = partnerId;
}

@Column(name = "employee_ID", nullable = false)
public int getemployeeId() {
    return this.employeeId;
}

public void setemployeeId(int employeeId) {
    this.employeeId = employeeId;
}

@Id @GeneratedValue(strategy=GenerationType.SEQUENCE, generator="SEQ_STORE")
@Column(name = "order_ID",insertable=false, nullable=false,  updatable=false)
public int getOrderId() {
    return this.orderId;
}

public void setOrderId(int orderId) {
    this.orderId = orderId;
}

public boolean equals(Object other) {
    if ((this == other))
        return true;
    if ((other == null))
        return false;
    if (!(other instanceof OrderId))
        return false;
    OrderId castOther = (OrderId) other;

    return (this.getpartnerId() == castOther.getpartnerId())
            && (this.getemployeeId() == castOther.getemployeeId())
            && (this.getOrderId() == castOther.getOrderId());
}

public int hashCode() {
    int result = 17;

    result = 37 * result + this.getpartnerId();
    result = 37 * result + this.getemployeeId();
    result = 37 * result + this.getOrderId();
    return result;
}

}

Answer 1

我一直徘徊在万维网上的所有可能的链接上,并试图找到为什么你不能将@GeneratedValue与@EmbeddedId或@IdClass(即复合PK)一起使用.原因是你不能.这里提供的解释可能会帮助您感觉更好: JAVA.NET/GLASSFISH

复合PK是基于ASSIGNMENT的而不是基于GENERATION的.因此,任何@GeneratedValue内容都不适用于它们.我的项目也有问题,我认为除此之外别无他法:

如果您知道您的@GeneratedValue ID在您的域(例如,您的数据库)的上下文中始终是唯一的,则您不需要使用复合PK并进行一些内部检查以确定记录的唯一性(即持久性对象集合) .