Re: two different databases at same time?
Re: two different databases at same time?
- Subject: Re: two different databases at same time?
- From: David LeBer <email@hidden>
- Date: Wed, 4 Aug 2010 14:20:43 -0400
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.
>
> 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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