Hibernate : Fetch collection -

-

i encontered problem while trying collection of elements : set of friend empty.

there 3 classes : 

@entity @table(name="user") public class user { @id @column(name="user_id", nullable=false)  private string mail;  @column(name="password") private string password;  @column(name="surname") private string surname;  @column(name="name") private string name = null;  @column(name="statut") private statutuser statut;  @column(name="phonenumber") private int phonenumber;  @onetomany(cascade = cascadetype.persist, mappedby="friendpk.friend") @fetch(fetchmode.join)     private set<friend> friends = new hashset<friend>();      ...      getters , setters

the second 1 : 

@entity @table(name = "friend") public class friend {  @embeddedid  public friendpk friendpk;  @column(name = "friend_statut") private statutfriend statutfriend;  ...  }

the last 1 : 

@suppresswarnings("serial") @embeddable  public class friendpk implements serializable{      @manytoone     @joincolumn(name="user1_id", referencedcolumnname="user_id")     protected user user1;      @manytoone     @joincolumn(name="user2_id", referencedcolumnname="user_id")     protected user friend; }

when try friends' user, collection empty.

here's file method add relationship :

private entitymanagerfactory emf; private entitymanager manager;  public string addfriends(string mail1, string mail2){          entitytransaction t;         t = manager.gettransaction();          try{             t.begin();              user user = manager.find(user.class, mail1);              user friend =  manager.find(user.class, mail2);              friend f = new friend();             f.setstatutfriend(statutfriend.tocheck);             friendpk friendpk = new friendpk();             friendpk.setfriend(friend);             friendpk.setuser1(user);             f.setfriendpk(friendpk);              set<friend> relationship = new hashset<friend>();             relationship =  user.getfriends();             relationship.add(f);              set<friend> relationship2 = new hashset<friend>();             relationship2 = friend.getfriends();             relationship2.add(f);              user.setfriends(relationship);             friend.setfriends(relationship2);              manager.persist(user);              t.commit();             error.setreq(statutreq.done);         }         catch(exception e){             error.setreq(statutreq.aborted);             error.seterror(e.getmessage());         }                 {             if (t.isactive())             {                 t.rollback();             }         }

please indulgent code... i'm beginner ! lot.

at first sight, code seems correct despite architecture looks strange. class friendfk stand ? doesn't user need hold set of users set ? database point of view, relational table necessary not in java model.

if you, delete class , use hbm2dll tool generate correct matching database schema.

could specify hibernate , jars versions , give hibernate config file check it.


Comments

Post a Comment

Popular posts from this blog

java - Jmockit String final length method mocking Issue -

-
using jmockit 1.2 jar, trying mock string's length method getting unexpected invocation exception: failed: test java.lang.illegalstateexception: missing invocation mocked type @ point; please make sure such invocations appear after declaration of suitable mock field or parameter @ stringdemo.testa$1.<init>(testa.java:17) @ stringdemo.testa.test(testa.java:13) i using testng: @test public void test() throws exception { new expectations() { @mocked("length") string astring; { astring.length(); result = 2; } }; system.out.println(a.showa("test")); } } actual class a: public class { public static int showa(string str){ int a= str.length(); return a; } } this wrong way of recording expected results. shouldn't mock , record string's length() method, record showa() instead. here solution @suppresswarnings("unused...
Read more

What is the difference between data design and data model(ERD) -

-
i have google question , find answer in day. know, data design many many table have list column,and mark pk , fk. why er-diagram have find this? data design process of designing database. main output of data design detailed logical data model of database. some people data design includes of needed logical , physical design choices , physical storage parameters needed generate design in data definition language. technically, database analysis, database analysts (dbas) trained do. while person can both data design , database analysis, these 2 different tasks. data design models data. database analysis takes model , applies 1 or more database engines (relational, hierarchical, nosql). a logical data model 1 of main outputs of data design. data model represented entity relationship diagram, or er diagram.
Read more

ios - Can NSManagedObject conform to NSCoding -

-
i need transfer single object across device. right converting nsmanagedobject dictionary , archiving , sending nsdata. upon receiving unarchiving it. transfer nsmanagedobject archiving , unarchiving instead of creating intermediate data object. @interface test : nsmanagedobject<nscoding> @property (nonatomic, retain) nsstring * title; @end @implementation test @dynamic title; - (id)initwithcoder:(nscoder *)coder { self = [super init]; if (self) { self.title = [coder decodeobjectforkey:@"title"]; //<crash } return self; } - (void)encodewithcoder:(nscoder *)coder { [coder encodeobject:self.title forkey:@"title"]; } @end nsdata *archivedobjects = [nskeyedarchiver archiveddatawithrootobject:testobj]; nsdata *objectsdata = archivedobjects; if ([objectsdata length] > 0) { nsarray *objects = [nskeyedunarchiver unarchiveobjectwithdata:objectsdata]; } the problem above code is. crashes @ self.title in initwithcoder sa...
Read more