Re: two different databases at same time?
Re: two different databases at same time?
- Subject: Re: two different databases at same time?
- From: Joe Little <email@hidden>
- Date: Wed, 4 Aug 2010 11:26:19 -0700
On Wed, Aug 4, 2010 at 11:20 AM, David LeBer
<email@hidden> 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.
>
>>
>> Am I just missing some clue that others already have?
>>
>> On Thu, Apr 1, 2010 at 8:17 PM, Cheong Hee <email@hidden> 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@hidden>
>>> To: "Cheong Hee" <email@hidden>
>>> Cc: "WO Dev Group" <email@hidden>
>>> 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@hidden>
>>>> To: "James Cicenia" <email@hidden>
>>>> Cc: "WO Dev Group" <email@hidden>
>>>> 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.
>>>>> _______________________________________________
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>>>
>>> ;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
>>>
>>>
>>>
>>>
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>
> ;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
>
>
>
>
>
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