Multiple-to-one foreign key Association in hibernate annotation

Assume that a farm produces multiple plants. A specific plant is produced on a farm.

1 package net. yeah. fancydeepin. po;
2
3 import java. io. Serializable;
4 import javax. persistence. Column;
5 import javax. persistence. Entity;
6 import javax. persistence. GeneratedValue;
7 import javax. persistence. Id;
8 /**
9 *-----------------------------------------
10 * @ describe farm
11 * @ author fancy
12 * @ email fancydeepin@yeah.net
13 * @ 2012-10-21 <p>
14 *-----------------------------------------
15 */
16 @ Entity
17 public class Farm implements Serializable {
18
19 private static final long serialVersionUID = 1L;
20
21 private Integer id;
22 private String name;
23
24 @ Id
25 @ GeneratedValue
26 public Integer getId (){
27 return id;
28}
29 @ Column (length = 18, nullable = false)
30 public String getName (){
31 return name;
32}
33 public void setId (Integer id ){
34 this. id = id;
35}
36 public void setName (String name ){
37 this. name = name;
38}
39}

1 package net. yeah. fancydeepin. po;
2
3 import java. io. Serializable;
4 import javax. persistence. CascadeType;
5 import javax. persistence. Column;
6 import javax. persistence. Entity;
7 import javax. persistence. FetchType;
8 import javax. persistence. GeneratedValue;
9 import javax. persistence. Id;
10 import javax. persistence. ManyToOne;
11 /**
12 *-----------------------------------------
13 * @ describe plants
14 * @ author fancy
15 * @ email fancydeepin@yeah.net
16 * @ 2012-10-21 <p>
17 *-----------------------------------------
18 */
19 @ Entity
20 public class Plant implements Serializable {
21
22 private static final long serialVersionUID = 1L;
23
24 private Integer id;
25 private String name;
26 private Farm farm;
27
28 @ Id
29 @ GeneratedValue
30 public Integer getId (){
31 return id;
32}
33 @ Column (length = 18, nullable = false)
34 public String getName (){
35 return name;
36}
37 @ ManyToOne (cascade = CascadeType. PERSIST, optional = false, fetch = FetchType. LAZY)
38 public Farm getFarm (){
39 return farm;
40}
41 public void setId (Integer id ){
42 this. id = id;
43}
44 public void setName (String name ){
45 this. name = name;
46}
47 public void setFarm (Farm farm ){
48 this. farm = farm;
49}
50
51}

Junit test:

1 @ Test
2 public void createTable (){
3
4 new SchemaExport (new AnnotationConfiguration (). configure (). create (true, true );
5}

Run the unit test above. The structure of the table generated in the database is as follows:

 

Cascade storage:

1 private static Session session;
2
3 @ BeforeClass
4 public static void beforeClass (){
5
6 session = new AnnotationConfiguration (). configure (). buildSessionFactory (). getCurrentSession ();
7}
8
9 @ Test
10 public void insert (){
11 try {
12 Farm farm = new Farm ();
13 farm. setName ("fancy-farm ");
14 Plant tomato = new Plant ();
15 tomato. setName ("tomato ");
16 tomato. setFarm (farm );
17 Plant cabbage = new Plant ();
18 cabbage. setName ("cabbage ");
19 cabbage. setFarm (farm );
20 session. beginTransaction ();
21 session. persist (tomato );
22 session. persist (cabbage );
23 session. getTransaction (). commit ();
24} catch (Exception e ){
25 e. printStackTrace ();
26}
27}