[jboss-user] [EJB 3.0] - merge one-to-one strategy

hi all, I am having troubles understanding the EJB3 updating strategy. I am familar with the traditional mechanism of dealing with just FK when updating a one-to-one relationship. However with EJB3 the FK is now a object. It loads both foreign key objects before setting, then persisting. | public double calculate (int fundId, int investorId, double saving) { | 26 | 27 Investor investor = | 28 em.find(Investor.class, | 29 Integer.valueOf(investorId)); | 30 Fund fund = | 31 em.find(Fund.class, | 32 Integer.valueOf(fundId)); | 33 | 34 int start = investor.getStartAge(); | 35 int end = investor.getEndAge(); | 36 double growthrate = fund.getGrowthrate(); | 37 | 38 double tmp = Math.pow(1. + growthrate / 12., 12. * (end - start) + 1); | 39 double result = saving * 12. * (tmp - 1) / growthrate; | 40 Timestamp ts = new Timestamp (System.currentTimeMillis()); | 41 | 42 TimedRecord rec = | 43 new TimedRecord (fund, investor, saving, result, ts); | 44 em.persist (rec); | 45 | 46 return result; | 47 } | Is the same mechanism required when updating? Unfortunetly the EJB3trail does not have a one-to-one merge example. Is something like the following performant or are there better mechanisms? The major issue is executing the load of the FK relationship object. Which seems expensive when i already have the FK id. | | strategy 1 | | public double update (int recId, int fundId, int investorId, double saving) { | | Investor investor = | em.find(Investor.class, | Integer.valueOf(investorId)); | Fund fund = | em.find(Fund.class, | Integer.valueOf(fundId)); | TimeRecord rec = | em.find(Fund.class, | Integer.valueOf(fundId)); | | rec.setSaving( saving); | rec.setFund( fund ); | rec.setInvestor( investor ); | em.merge (rec); | | return result; | } | I have tried the following with little success as it complains about transient Objects | | strategy 2 not working. | | public double update2 (int recId, int fundId, int investorId, double saving) { | | Investor investor =new Investor( investorId); | Fund fund = new Fund( fundId); | TimeRecord rec = | em.find(Fund.class, | Integer.valueOf(fundId)); | | rec.setSaving( saving); | rec.setFund( fund ); | rec.setInvestor( investor ); | em.merge (rec); | | return result; | } | | So my question is does the merge on one-to-one relationship require fullly populated detached objects or can it be done with just the id for the FK? many thanks -lp View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=3982272#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...