onetomany unidirectional with jointable setup using jpa(onetomany unidirectional with jointable setup using jpa)

 我有两个实体，即客户关系和订单关系。 一个客户可以拥有多个订单。 因为我需要这种关系是单向的，所以我使用的是joinTable。 
 
 我可以使用JPA向我的客户实体添加条目。 我可以使用JPA向我的订单实体添加条目。 
 
 我想知道如何将两者连接在一起的数据。 假设我在客户表中有一个条目，在订单表中有两个条目。 我想将order表中的这两个条目与customer表中的一个条目相关联。 
 
 目前，我在jointable customer_order中没有看到任何条目。 我如何建立关联？ 我想当我将订单添加到订单表中时，我将不得不以某种方式提及客户ID号。 不知道该怎么做。 在JPA中是否有标准查询？ 
 
 谢谢。 
 
 客户类 - 
 
@Entity
public class Customer implements Serializable {
    @Id
    @GeneratedValue(strategy = GenerationType.TABLE, generator = "generatorCustomer")
    @TableGenerator(name = "generatorCustomer", allocationSize = 1)
    @Column(name="customer_id")
    private Long id;
    public Long getId() {
        return id;
    }

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

    @OneToMany()
    @JoinTable (
        name="customer_order",
        joinColumns={ @JoinColumn(name="customer_id", referencedColumnName="customer_id") },
        inverseJoinColumns={ @JoinColumn(name="order_id", referencedColumnName="order_id", unique=true) }
    )
    private List<Order> orderList = new ArrayList<Order>();
    public List<Order> getOrderList() {
        if(this.orderList == null) {
            this.orderList = new ArrayList<Order>();
        }
        return this.orderList;
    }

    public void setOrderList(List<Order> orderList) {
        this.orderList = orderList;
    }

    public void addOrder(Order order) {
        this.orderList.add(order);
    }

    /* other logic follows......... */
}
 
 订单类 - 
 
@Entity
public class Order implements Serializable {
@Id
@GeneratedValue
@Column(name="order_id")
private Long id;
public Long getId() {
    return id;
}

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

/* other logic follows......... */
}
 
 客户表说明： 
 
jbossql=# \d customer
Column   |         Type          |                        Modifiers
-------------+-----------------------+---------------------------------------------------------------
customer_id | bigint                | not null default nextval('customer_customer_id_seq'::regclass)
name        | character varying(50) | 
Indexes:
"customer_pkey" PRIMARY KEY, btree (customer_id)
Referenced by:
TABLE "customer_order" CONSTRAINT "fk8ef2f420ec016855" FOREIGN KEY (customer_id) REFERENCES customer(customer_id)
 
 订单表说明： 
 
jbossql=# \d order
Column   |  Type  | Modifiers 
------------+--------+-----------
order_id   | bigint | not null
value      | real   | 
Indexes:
"order_pkey" PRIMARY KEY, btree (order_id)
Referenced by:
TABLE "customer_order" CONSTRAINT "fk1e4828a98187660" FOREIGN KEY (order_id) REFERENCES order(order_id)
 
 customer_order联合表描述： 
 
jbossql=# \d customer_order
Column       |  Type  | Modifiers 
--------------+--------+-----------
customer_id  | bigint | not null
order_id     | bigint | not null
Indexes:
"customer_order_order_id_key" UNIQUE CONSTRAINT, btree (order_id)
Foreign-key constraints:
"fk1e4828a98187660" FOREIGN KEY (order_id) REFERENCES order(order_id)
"fk1e4828adba386b8" FOREIGN KEY (customer_id) REFERENCES customer(customer_id)
 
 我可以在customer表中插入一个项目： 
 
jbossql=# select * from customer;
customer_id | name 
-------------+-------------
1        | joe
(1 row)
 
 我也可以将项目插入到oder表中： 
 
jbossql=# select * from order;
order_id | value 
----------+-----------
1       |  1.8
2       |  0.5
(2 rows)
 
 我以为customer_order表会自动填充，即hibernate会采取这种方式。 但似乎不是因为我的连接表是空的： 
 
jbossql=# select * from customer_order;
customer_id | order_id 
-------------+-----------
(0 rows)
 
 所以，我的目的是让这两个订单条目与客户乔相关联。 
 
 请帮忙。 
 
 
 
 我是否必须向customer_order表明确添加记录？ 
 
 
 如果没有，我如何将项目插入订单表，以便我可以将该条目连接到特定客户？ 
 
 
 我的映射是否正确在这个OneToMany [unidirection]关系的java文件中按预期工作 
 
 
 我正在使用JPA2和JBoss以及Hibernate。 你有任何代码参考TEST一对多的关系吗？ 对完整项目或阅读材料的任何参考都会有所帮助。 
 
 
 谢谢你的期待。 

I have two entities namely customer and order in a onetomany relationship. One customer can have multiple orders. Since i needed this relationship to be unidirectional, i am using a joinTable.
 
I am able to add entries to my customer entity using JPA. I am able to add entries to my order entity using JPA.
 
I am wondering how to connect the two together data. Let's say i have one entry in customer table and two entries in order table. I would like to associate these two entries in order table to the one entry in customer table.
 
Currently, i don't see any entries in my jointable customer_order. How do i make the association? I guess while i am adding the orders into the order table, i will have to mention the customer id number somehow. Not sure how to do that. Is there a criteria query for that in JPA?
 
Thanks.
 
Customer Class -
 
@Entity
public class Customer implements Serializable {
    @Id
    @GeneratedValue(strategy = GenerationType.TABLE, generator = "generatorCustomer")
    @TableGenerator(name = "generatorCustomer", allocationSize = 1)
    @Column(name="customer_id")
    private Long id;
    public Long getId() {
        return id;
    }

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

    @OneToMany()
    @JoinTable (
        name="customer_order",
        joinColumns={ @JoinColumn(name="customer_id", referencedColumnName="customer_id") },
        inverseJoinColumns={ @JoinColumn(name="order_id", referencedColumnName="order_id", unique=true) }
    )
    private List<Order> orderList = new ArrayList<Order>();
    public List<Order> getOrderList() {
        if(this.orderList == null) {
            this.orderList = new ArrayList<Order>();
        }
        return this.orderList;
    }

    public void setOrderList(List<Order> orderList) {
        this.orderList = orderList;
    }

    public void addOrder(Order order) {
        this.orderList.add(order);
    }

    /* other logic follows......... */
}
 
Order Class -
 
@Entity
public class Order implements Serializable {
@Id
@GeneratedValue
@Column(name="order_id")
private Long id;
public Long getId() {
    return id;
}

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

/* other logic follows......... */
}
 
Customer table description:
 
jbossql=# \d customer
Column   |         Type          |                        Modifiers
-------------+-----------------------+---------------------------------------------------------------
customer_id | bigint                | not null default nextval('customer_customer_id_seq'::regclass)
name        | character varying(50) | 
Indexes:
"customer_pkey" PRIMARY KEY, btree (customer_id)
Referenced by:
TABLE "customer_order" CONSTRAINT "fk8ef2f420ec016855" FOREIGN KEY (customer_id) REFERENCES customer(customer_id)
 
Order Table description:
 
jbossql=# \d order
Column   |  Type  | Modifiers 
------------+--------+-----------
order_id   | bigint | not null
value      | real   | 
Indexes:
"order_pkey" PRIMARY KEY, btree (order_id)
Referenced by:
TABLE "customer_order" CONSTRAINT "fk1e4828a98187660" FOREIGN KEY (order_id) REFERENCES order(order_id)
 
customer_order joint table description:
 
jbossql=# \d customer_order
Column       |  Type  | Modifiers 
--------------+--------+-----------
customer_id  | bigint | not null
order_id     | bigint | not null
Indexes:
"customer_order_order_id_key" UNIQUE CONSTRAINT, btree (order_id)
Foreign-key constraints:
"fk1e4828a98187660" FOREIGN KEY (order_id) REFERENCES order(order_id)
"fk1e4828adba386b8" FOREIGN KEY (customer_id) REFERENCES customer(customer_id)
 
I am able to insert an item into the customer table:
 
jbossql=# select * from customer;
customer_id | name 
-------------+-------------
1        | joe
(1 row)
 
I am able to insert items into the oder table as well:
 
jbossql=# select * from order;
order_id | value 
----------+-----------
1       |  1.8
2       |  0.5
(2 rows)
 
I was thinking the customer_order table would automatically get populated i.e hibernate would take of that. But appears not because my jointable is empty:
 
jbossql=# select * from customer_order;
customer_id | order_id 
-------------+-----------
(0 rows)
 
So, my intention is to make those two order entries connected to customer joe.
 
Please help.
 
 
 
Do i have to explicitly add a record to the customer_order table?
 
 
If not, how do i insert items into order table so that i can connect that entry to a particular customer?
 
 
Are my mappings right in the java files for this OneToMany [unidirection] relationship to work as expected
 
 
I am using JPA2 and JBoss and Hibernate. Do you have any code references to TEST a one-to-many relationship? Any references for a complete project or reading material would help.
 
 
Thanks for looking.

原文：https://stackoverflow.com/questions/15374334