Database-operations on Recursive data using hibernate

During work, we often encounter data with recursive records. The most common is the data of a department node of an organization. A node must have a parent node attribute, at the same time, it may have several subnodes. All node data is stored in a table in the database. This phenomenon is called the Composite mode in the design mode. Next I will give an example of using hibernate to operate such a table. For the hibernate configuration and table structure creation section, please refer to my previous article 《Example of using the weblogic data source as the hibernate Data Source"

1. Persistence class Node. java

1. PackageCom. jarie. business. organization;
3. /**
4. *

   Title:

5. *

   Description: department node

6. *

   Copyright: Copyright (c) 2003

7. *

   Company: www.jagie.com

8. * @ Author Jagie
9. * @ Version 1.0
10. */
12. Public ClassNode {
13. Private StringID;// Pk
14. Private StringName;// Name
15. Private StringDescription;// Description
16. PrivateNode parent;// Superior department
17. PrivateJava. util.SetChildren;// Subordinate departments
18. Public Static VoidMain (String[] Args ){
19. }
20. Public StringGetID (){
21. ReturnID;
22. }
23. Public VoidSetID (StringID ){
24. This. ID = ID;
25. }
26. Public StringGetName (){
27. ReturnName;
28. }
29. Public VoidSetName (StringName ){
30. This. Name = name;
31. }
32. PublicNode getParent (){
33. ReturnParent;
34. }
35. Public VoidSetParent (Node parent ){
36. This. Parent = parent;
37. }
38. Public StringGetDescription (){
39. ReturnDescription;
40. }
41. Public VoidSetDescription (StringDescription ){
42. This. Description = description;
43. }
44. Public StringToString (){
45. ReturnName;
46. }
47. PublicJava. util.SetGetChildren (){
48. ReturnChildren;
49. }
50. Public VoidSetChildren (java. util.SetChildren ){
51. This. Children = children;
52. }
53. }

2. Map File Node. hbm. xml

 


 
  
  
  
   
    
   
    
      
    
    
    
    
    
    
    
    
    
    
    
    
     
      
     
     
      
     
     
    
     
    
     
            column="parent" name="parent" />
      
  
      

     
    
   
  
 

3. Use SchemaExport to create a database (omitted)

4. Test code snippet

1.  // Obtain net. sf. hibernate. Session and net. sf. hibernate. Transaction;
2. Session s = JDOUtils. getInstance (). getSessionFactory (). openSession ();
3. Transaction t = s. beginTransaction ();
4.  // Create a parent node
5. Node org =NewNode ();
6. Org. setName ("Beijing Head Office ");
7. Org. setDescription ("this is Beijing Head Office ");
9.  // Create a subnode
10. Node org2 =NewNode ();
11. Org2.setName ("Haidian branch ");
12. Org2.setDescription ("this is the Haidian branch ");
13.  // Create a subnode reference to the parent node
14. Org2.setParent (org );
15. &