Using JPA CompositeKey uses a property from another Entity -


i tried searching having problems finding want. have following schema( * indicates primary key)

user   *userid   -desc registration   *deviceid   *userid   -date

so want create primary key registration like...

@embeddable public class regpk{     private string deviceid;     private user user;     @column(name="dev_id")     public string getdevid(){       return deviceid;     }     ...     @manytoone     @joincolumn(name="user_id", referencedcolumnname="user_id")     public user getuser() {       return user;     }     ... }

is right? update user_id field update in registration when persist?

when try kind of thing out following....

[10/7/13 13:37:07:156 edt] 000000ae webapp e com.ibm.ws.webcontainer.webapp.webapp logservleterror srve0293e: [servlet error]-[hello]: org.apache.openjpa.util.metadataexception: id class specified type "class org.me.mfa.jpa.registration" not match primary key fields of class. make sure identity class has same primary keys persistent type, including pk field types. mismatched property: "user"

so now?

jpa not allow primary key classes contain relationships, basic types. jpa 2.0 allows relationships apart of id, move relationship entity class, , have regpk contain deviceid , userid. device-user relationship marked either @id or @mapsid("user") depending on if wanted use @pkclass or @embeddedid within entity. see http://wiki.eclipse.org/eclipselink/examples/jpa/2.0/derivedidentifiers example using pk class.

in jpa 1.0, use similar setup, except device-user relationship marked read-only (either specifying @primarykeyjoincolumn annotation, or marking @joincolumn insertable=false, updatable=false). need set primary key basic mapping value manually, pulling value referenced user entity directly. of course requires id in user assigned, might require additional work if both objects new.


Comments

Post a Comment

Popular posts from this blog

c++ - CryptStringToBinary API behavior -

i seeing strange behavior cryptstringtobinary cryptography api. please see below code (config: x64 debug): #include "stdafx.h" #include <windows.h> #include <strsafe.h> #include <iostream> #include <exception> void main() { dword dwskip; dword dwflags; dword dwdatalen; //lpcwstr pszinput = l"jaaaaaecaaadzgaaakqaagdnnl1l56bwgfjdgr3rpxtqqqn6daw3usv2emkjym4t"; //this works fine lpcwstr pszinput = l"mytest"; //doesnt work, api returns false,error code 0x0000000d // determine size of byte array , allocate memory. if(! cryptstringtobinary( pszinput, _tcslen( pszinput ) + 1, crypt_string_base64, null, &dwdatalen, &dwskip, &dwflags ) ) { dword dw = getlasterror(); //0x0000000d: data invalid throw std::exception( "error computing byte length." ); } byte *pbytebyte = null; try { ...
Read more

java.util.scanner - How to read and add only numbers to array from a text file -

i'm learning java , have question regarding reading file want read numbers file contains strings well. here example of file: 66.56 "3 java 3-43 5-42 2.1 1 and here coding: public class test { public static void main (string [] args){ if (0 < args.length) { file x = new file(args[0]); try{ scanner in = new scanner( new fileinputstream(x)); arraylist<double> test = new arraylist<>(); while(in.hasnext()){ if(in.hasnextdouble()){ double f=in.nextdouble(); test.add(f);} else {in.next();} } catch(ioexception e) { system.err.println("exception during reading: " + e); } } my problem add 66.56,2.1 , 1 doesn't add 3 after "3 or ignores 3-43 , 5-42 can tell me how skip strings , add doubles here? thanks all said 3 ie; "3, 3-43 , 4-42 strings either u read string , split , check number @ " , - or put in space between characters , integers. jvm after compilation tre...
Read more

iphone - Three second countdown in cocos2d -

i trying have 3 second countdown display when level beat in game. did: -(void) gamesegmentbeat { [self pauseschedulerandactions]; // overlay game opaque background ccsprite *opaquebg = [ccsprite spritewithfile:@"background1.png"]; opaquebg.position = screencenter; [self addchild:opaquebg z:10000]; // these 3 labels 3 seconds cclabelttf *three = [cclabelttf labelwithstring:@"3" fontname:@"helvetica" fontsize:100]; three.position = ccp(screencenter.x, screencenter.y); cclabelttf *two = [cclabelttf labelwithstring:@"2" fontname:@"helvetica" fontsize:100]; two.position = ccp(screencenter.x, screencenter.y); cclabelttf *one = [cclabelttf labelwithstring:@"1" fontname:@"helvetica" fontsize:100]; one.position = ccp(screencenter.x, screencenter.y); // secondspast specified in update method secondspast = 0; if (secondspast == 1) { [self addchild:thr...
Read more