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: Thu, 5 Aug 2010 22:07:28 -0700
I just checked and my models do indeed have a complete URL, etc in
their default connection dictionaries.
On Thu, Aug 5, 2010 at 7:57 PM, Cheong Hee (Gmail) <email@hidden> wrote:
> Will there make any difference if these connection dictionaries is defined
> in respective model db url?
>
> ----- Original Message ----- From: "Joe Little" <email@hidden>
> To: "Joe Little" <email@hidden>
> Cc: "Cheong Hee (Gmail)" <email@hidden>; "David LeBer"
> <email@hidden>; "WO Dev Group"
> <email@hidden>
> Sent: Friday, August 06, 2010 2:17 AM
> Subject: Re: two different databases at same time?
>
>
> So, I'm starting to wonder if something broke/changed in Wonder. I've set up
> test projects that list two DBs in the Properties file for two models, but
> only one is ever added to the connection dictionary. Does there need to
> workable values for the default database in the eomodeld directory itself?
>
> This has worked for me before, with one framework model and one local
> project model. This time, i have two models in one framework.
>
>
> On Aug 4, 2010, at 7:26 PM, Joe Little <email@hidden> wrote:
>
>> 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@hidden>
>> 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@hidden>
>>> To: "Joe Little" <email@hidden>
>>> Cc: "Cheong Hee" <email@hidden>; "WO Dev Group"
>>> <email@hidden>
>>> 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@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.
>>>
>>> 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@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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>>>>>>>>
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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
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>> _______________________________________________
>>>>>>> Do not post admin requests to the list. They will be ignored.
>>>>>>> Webobjects-dev mailing list (email@hidden)
>>>>>>> Help/Unsubscribe/Update your Subscription:
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>>>>>>>
>>>>>>> This email sent to email@hidden
>>>>>>>
>>>>>
>>>>> ;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
>>>
>>>
>>>
>>>
>>>
>
>
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