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From Kevin Williams <kevin...@qwest.net>
Subject Re: [DAS Java] created SDO graph doubt
Date Mon, 09 Apr 2007 15:36:50 GMT
Hello Adriano,
To return a graph of related elements, the RDB DAS depends on the user 
providing a Query that expresses the relationship between the elements.  
This is most often done by providing a query that includes a join.  See 
the "relationship" examples in the DAS test suite.
Thanks,
--Kevin


Adriano Crestani wrote:

> Another doubt:
>
> I have the following tables on my database:
>
> create table B (
>    ID INTEGER NOT NULL PRIMARY KEY
> );
>
> create table A (
>    ID INTEGER NOT NULL PRIMARY KEY,
>    B_ID INTEGER,
>    FOREIGN KEY (B_ID) REFERENCES B(ID)
> );
>
> OK, then I was analyzing the generated sdo graph when I execute the query
> "select * from A, B;", I got something like this:
>
> Graph1:
> http://cwiki.apache.org/confluence/download/attachments/45093/das_graph.JPG 
>
>
> I understand the column B_ID would be considered only an integer 
> column when
> of table A when there is no B table returned on the query. However, the B
> table is also returned on the query and as the B_ID column is a FK to the
> table B, shouldn't the graph be like this?:
>
> Graph2:
> http://cwiki.apache.org/confluence/download/attachments/45093/das+graph+as+I+suppose+it+shoud+be.JPG

>
>
> This way I think the data returned by the query would be better 
> represented
> on the graph. Maybe there is a reason for the graph to be generated as
> Graph1 instead of Graph2.
> What do you say guys?
>
> Adriano Crestani
>
> On 4/5/07, Adriano Crestani <adrianocrestani@gmail.com> wrote:
>
>>
>> Thanks kelvin ; )
>>
>> Adriano Crestani
>>
>> On 4/4/07, Kevin Williams <kevincbw@qwest.net> wrote:
>> >
>> > The RDB DAS will only populate a graph with data returned from the 
>> used
>> > query.  If you want a graph that contains data from related tables 
>> then
>> > the query provided must return that data (typically a join).  The
>> > relationship tests in the test suite demonstrate this.
>> > --Kevin
>> >
>> > Adriano Crestani wrote:
>> >
>> > > Let me try to explain my doubt:
>> > >
>> > > Lets suppose I create a select command and execute it. The returned
>> > > ResultSet has an attribute that belongs to the table X and is a 
>> FK to
>> > the
>> > > table Y, but no Y attribute is contained in the ResultSet. The
>> > > question is:
>> > > does the das create, and also populate, the SDO graph only with the
>> > > metadata
>> > > and data contained in the ResultSet or the das also adds to the SDO
>> > graph
>> > > the referenced Y table and its attributes and keep doing it till 
>> there
>> > > is no
>> > > more referenced table?
>> > >
>> > > I expect to be clear enough ; )
>> > >
>> > >
>> > > Adriano Crestani
>> > >
>> >
>> >
>> >
>> > ---------------------------------------------------------------------
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>> >
>> >
>>
>



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