You gave me a good clue. I may be using the same damn ec On Aug 4, 2010, at 7:17 PM, "Cheong Hee \(Gmail\)" <[email protected]> wrote:
> When the question posted, I intended to find out if the different db works in > the same ec. I have not thought more on the storing and fetching. > > I am not sure if this is right but merely bring it out for better > understanding. Please point out whichever does not seem right: > > Said the Student table is in databaase A. The AdmitApplicant table is stored > in database B. > A row admitApplicantID is created in Student table and a relationship should > be defined, said admitApplicant. The modelling cross different database > should be fine. > > If I understand what David mentioned, the EOF fetch through relationship > admitApplicant will fail. Therefore, I will assume that the fetch will have > to be done by getting the admitApplicant key from Student, and then use the > key to search the AdmitApplicant that is resided in database B. Good thing > is both could be done in the same ec. > > Cheers > > Cheong Hee > > ----- Original Message ----- From: "David LeBer" <[email protected]> > To: "Joe Little" <[email protected]> > Cc: "Cheong Hee" <[email protected]>; "WO Dev Group" > <[email protected]> > Sent: Thursday, August 05, 2010 2:36 AM > Subject: Re: two different databases at same time? > > > > On 2010-08-04, at 2:26 PM, Joe Little wrote: > >> On Wed, Aug 4, 2010 at 11:20 AM, David LeBer >> <[email protected]> wrote: >>> >>> On 2010-08-04, at 2:12 PM, Joe Little wrote: >>> >>>> Digging up an old thread. This is the first time I'm creating a >>>> multi-database relation. When my migrations kick off to generate my >>>> newer database that has a single relation to the old, it fails in >>>> spectacular ways. >>>> >>>> Specifically, it has this error: >>>> >>>> Caused by: java.lang.RuntimeException: Failed to execute 'ALTER TABLE >>>> STUDENT ADD CONSTRAINT STUDENT_admitApplicantID_ID_FK FOREIGN KEY >>>> (admitApplicantID) REFERENCES ADMIT_APPLICANT (ID) DEFERRABLE >>>> INITIALLY DEFERRED'. >>>> PSQLException: ERROR: relation "admit_applicant" does not exist >>>> >>>> student has a relation to admit_applicant, where student is >>>> db2.student and admit_applicant is db1.admit_applicant >>>> >>>> This is keyed off this migration line: >>>> >>>> studentTable.addForeignKey("admitApplicantID", "ADMIT_APPLICANT", "ID"); >>> >>> Don't do that. >>> >>> EOF is fine with cross database relationships but your DB probably isn't. >>> So it won't like you trying to create a foreign key constraint to a >>> different database, so don't. >> >> So, what is the alternative? Would a join table work -- I think that >> still has foreign key constraints. Or is it simply stating a differ >> type of join (not inner)? I haven't done this before so my lack of >> clue is telling. > > Sorry, I wasn't clear. Model the relationship in the EOModel, create a > vanilla row in the db that will act as a foreign key for the relationship, > but don't tell the db that it is a foreign key. Let EOF manage the > relationship for you. > >> >>> >>>> >>>> Am I just missing some clue that others already have? >>>> >>>> On Thu, Apr 1, 2010 at 8:17 PM, Cheong Hee <[email protected]> wrote: >>>>> Apparently I have complicated it by thinking of using multi ec to handle >>>>> respective database connections. Thanks for clarification.. >>>>> >>>>> Cheers >>>>> >>>>> Cheong Hee >>>>> >>>>> ----- Original Message ----- From: "David LeBer" >>>>> <[email protected]> >>>>> To: "Cheong Hee" <[email protected]> >>>>> Cc: "WO Dev Group" <[email protected]> >>>>> Sent: Thursday, April 01, 2010 8:23 PM >>>>> Subject: Re: two different databases at same time? >>>>> >>>>> >>>>> >>>>> On 2010-04-01, at 12:07 AM, Cheong Hee wrote: >>>>> >>>>>> Is there any pointers or sample code how these could be done to initiate >>>>>> connection and save changes in respective ec? >>>>> >>>>> You don't need multiple ec's unless you want them. Other than that it's >>>>> transparent. >>>>> >>>>> EOEditingContext ec = ERXEC.newEditingContext(); >>>>> Person p = (Person)EOUtitlites.createAndInsertInstance(ec, >>>>> Person.ENTITY_NAME); // Person entity persists in database A >>>>> Horse h = (Horse)EOUtitlites.createAndInsertInstance(ec, >>>>> Horse.ENTITY_NAME); >>>>> // Horse entity persists in database B >>>>> // make chagnes to h and p >>>>> ec.saveChanges(); // p saved to database A, h saved to database B >>>>> >>>>> You can model cross database relationships as long as you don't try and >>>>> create a fetch based on them. >>>>> >>>>>> >>>>>> Cheers >>>>>> >>>>>> Cheong Hee >>>>>> >>>>>> ----- Original Message ----- From: "Mark Ritchie" <[email protected]> >>>>>> To: "James Cicenia" <[email protected]> >>>>>> Cc: "WO Dev Group" <[email protected]> >>>>>> Sent: Thursday, April 01, 2010 1:05 AM >>>>>> Subject: Re: two different databases at same time? >>>>>> >>>>>> >>>>>>> On 31/Mar/2010, at 8:15 AM, James Cicenia wrote: >>>>>>>> >>>>>>>> Is it possible to use two different databases, I guess via two >>>>>>>> different >>>>>>>> models? >>>>>>>> I will need to connect to an Oracle big database on a remote server and >>>>>>>> was >>>>>>>> wondering if I could also use a mySQL or postgres database for user >>>>>>>> control >>>>>>>> on local server. >>>>>>> >>>>>>> Yes, yes! You can have multiple concurrent connections! One for each >>>>>>> EOModel! >>>>>>> Just make sure that the entity names are unique across all EOModels! >>>>>>> Good luck! >>>>>>> M. >>>>>>> _______________________________________________ >>>>>>> Do not post admin requests to the list. They will be ignored. >>>>>>> Webobjects-dev mailing list ([email protected]) >>>>>>> Help/Unsubscribe/Update your Subscription: >>>>>>> http://lists.apple.com/mailman/options/webobjects-dev/chng34%40gmail.com >>>>>>> >>>>>>> This email sent to [email protected] >>>>>> >>>>>> _______________________________________________ >>>>>> Do not post admin requests to the list. They will be ignored. >>>>>> Webobjects-dev mailing list ([email protected]) >>>>>> Help/Unsubscribe/Update your Subscription: >>>>>> >>>>>> http://lists.apple.com/mailman/options/webobjects-dev/dleber_wodev%40codeferous.com >>>>>> >>>>>> This email sent to [email protected] >>>>> >>>>> ;david >>>>> >>>>> -- >>>>> David LeBer >>>>> Codeferous Software >>>>> 'co-def-er-ous' adj. Literally 'code-bearing' >>>>> site: http://codeferous.com >>>>> blog: http://davidleber.net >>>>> profile: http://www.linkedin.com/in/davidleber >>>>> twitter: http://twitter.com/rebeld >>>>> -- >>>>> Toronto Area Cocoa / WebObjects developers group: >>>>> http://tacow.org >>>>> >>>>> >>>>> >>>>> >>>>> _______________________________________________ >>>>> Do not post admin requests to the list. They will be ignored. >>>>> Webobjects-dev mailing list ([email protected]) >>>>> Help/Unsubscribe/Update your Subscription: >>>>> http://lists.apple.com/mailman/options/webobjects-dev/jmlittle%40gmail.com >>>>> >>>>> This email sent to [email protected] >>>>> >>> >>> ;david >>> >>> -- >>> David LeBer >>> Codeferous Software >>> 'co-def-er-ous' adj. Literally 'code-bearing' >>> site: http://codeferous.com >>> blog: http://davidleber.net >>> profile: http://www.linkedin.com/in/davidleber >>> twitter: http://twitter.com/rebeld >>> -- >>> Toronto Area Cocoa / WebObjects developers group: >>> http://tacow.org >>> >>> >>> >>> >>> > > ;david > > -- > David LeBer > Codeferous Software > 'co-def-er-ous' adj. Literally 'code-bearing' > site: http://codeferous.com > blog: http://davidleber.net > profile: http://www.linkedin.com/in/davidleber > twitter: http://twitter.com/rebeld > -- > Toronto Area Cocoa / WebObjects developers group: > http://tacow.org > > > > > _______________________________________________ Do not post admin requests to the list. They will be ignored. Webobjects-dev mailing list ([email protected]) Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/webobjects-dev/archive%40mail-archive.com This email sent to [email protected]
