Re: Relationships

[Benjamin Venditti <be...@arcor.de>]

Hi Matt,

i just took a deeper look into the generation of foreign-key 
relationships, and it doesn't seem to be too difficult.
Therefore i already started and finished the first of my suggested steps 
"querried the DatabaseMetaDate for relations and populate the empire db 
model".
I hope you don't mind that started with it. I think a first working 
version should be finished by this evening (within the next 3-4 hours).

I'd be glad if you could have a look at my code, maybe i missed something.

Cherio
     Benjamin


Am 29.06.2011 15:12, schrieb Matt DeHoust:
> Thank you Benjamin and Rainer. I have subscribed to the dev list. I'll take
> a look at the code when I return from vacation and follow up using the dev
> list with any questions or ideas. I hope to have a chance to look into it
> this weekend.
>
> -Matt
>
> On Wed, Jun 29, 2011 at 6:30 AM, Rainer Döbele<do...@esteam.de>  wrote:
>
>> Hi everyone,****
>>
>> ** **
>>
>> I think this is an important improvement of the code generator that we
>> should implement.****
>>
>> I have created a Jira Issue for this:****
>>
>> ** **
>>
>> https://issues.apache.org/jira/browse/EMPIREDB-110****
>>
>> ** **
>>
>> Matt, if you feel you can and want to do It, then we would certainly
>> appreciate this.****
>>
>> You may create a patch file and attach it to the JIRA ticket.****
>>
>> Then we can apply the patch and commit the code to svn.****
>>
>> ** **
>>
>> For further discussion I would recommend to move to the dev-mailing list:*
>> ***
>>
>> empire-db-dev@incubator.apache.org****
>>
>> ** **
>>
>> Thanks, ****
>>
>> Rainer****
>>
>> ** **
>>
>> ** **
>>
>> *Von:* Benjamin Venditti [mailto:benjamin.venditti@arcor.de]
>> *Gesendet:* Mittwoch, 29. Juni 2011 01:47
>> *An:* empire-db-user@incubator.apache.org
>> *Cc:* Matt DeHoust
>> *Betreff:* Re: Relationships****
>>
>> ** **
>>
>> Hi Matt,
>>
>> thanks for your interest in empire-db.
>>
>> regarding your request ... unfortunately the codegen does not set up the
>> relation of the database model.
>> At the moment the codegen will only set up views and tables. We thought
>> these are the most important for the most people as they are usually
>> sufficient for simple data access.
>>
>> However i think there are two occasions where the relations are important:
>>      - database creation
>>      - deletion of records with cascading deletion enabled
>>
>> At the moment we have not planned to add "relationship generation"  to the
>> codegen component, but I am glad to hear that you consider to extend it on
>> your own.
>>
>> The right place to start with that would be:
>>     * CodeGenParser.populateDatabase(..) : 131* : This is the point where
>> the DatabaseMetaData is querried and used to populate empire-db's model
>>      *CodeGenWriter.generateCodeFiles(..) : 125* : Is used to serialize the
>> populated model as java code
>>      *src/main/resources/Database.vm :  70* : This is the velocity template
>> we use to create the java class for the database.
>>
>> In its default constructor you'd need to add a line for each relationship
>> similar to this:
>>
>>                                  *addRelation(
>> EMPLOYEES.DEPARTMENT_ID.referenceOn( DEPARTMENTS.DEPARTMENT_ID ));*
>>
>> I hope this is of some help to you. Feel free to ask if you have further
>> questions!
>>
>> Cherio
>>      Benjamin
>>
>> Am 28.06.2011 19:37, schrieb Matt DeHoust: ****
>>
>> Hello, ****
>>
>> ** **
>>
>> I see that the empire-db model supports relationships (for example
>> DBDatabase.getRelations()), but it doesn't seem that the codegen component
>> sets them up. Am I missing something? (I am using MySQL if that matters.)*
>> ***
>>
>> ** **
>>
>> If not, are there plans to introduce relationship setup in the codegen
>> component?****
>>
>> ** **
>>
>> If not, where should I look to add them myself? CodeGenParser?****
>>
>> ** **
>>
>> Thanks,****
>>
>> Matt****
>>
>> ** **
>>
>> P.S. I apologize if I posted this question twice by mitake.****
>>
>> ** **
>>