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Posted to ojb-user@db.apache.org by Wayne Kidd <gw...@audiobookcentral.com> on 2004/02/17 15:00:26 UTC
Re: Compound Primary Key foreign key references
Although this is, in fact the behavior of OJB, It seems that the right
behavior should be to describe the referenced tables primary key in the
sequence of the primary key definition. That is, if the primary key
constraint gives the order as x,z,y then the referencing table should
specify that its columns a,b,c refer to pk x,z,y with some syntax like
<foreignkey field-ref="a" refers-to="x"/>
<foreignkey field-ref="b" refers-to="z"/>
<foreignkey field-ref="c" refers-to="y"/>
instead of assuming the sequence of the column definitions in the other
table.
Wayne
Daniel.B.Brown@wellsfargo.com wrote:
> My question was the later. I could not find the behavior in the
> documentation.
>
> Thanks,
>
> - Dan
>
> -----Original Message-----
> From: Ron Gallagher [mailto:rgallagh@bellsouth.net]
> Sent: Monday, August 18, 2003 9:53 AM
> To: OJB Users List
> Subject: Re: Compound Primary Key foreign key references
>
>
> Dan --
>
> Are you asking this question because you've tried this configuration and it
> doesn't work, or are you just confused as to how OJB will handle this
> situation? If the former, then please provide more info regarding the
> problems you're having. If the latter, then here's my explanation...
>
> Anytime ojb encounters a reference-descriptor, it matches up the foreignkey
> elements, one for one, with the primary key field-descriptors in the
> referenced class. This matching process pairs up foreignkey and
> field-descriptor elements in the same order that they appear in the
> repository. So, in your case, the property mypackage.ClassA::keyA will be
> matched up with the property mypackage.ClassB::firstKey, and the property
> mypackage.ClassA::keyB will be matched up with the property
> mypackage.ClassB::secondKey
>
> Ron Gallagher
> Atlanta, GA
> rongallagher@bellsouth.net
>
>
>>From: Daniel.B.Brown@wellsfargo.com
>>Date: 2003/08/18 Mon AM 09:01:37 EDT
>>To: ojb-user@db.apache.org
>>Subject: Compound Primary Key foreign key references
>>
>>All,
>>
>> From what I can tell, the repository.dtd is not sufficient to uniquely
>>reference an object with a compound primary key. I think I must be
>
> missing
>
>>something. In the contrived example below the foreign keys used to
>>reference class B are keyA and keyB. Unfortunately, the names of keyA and
>>keyB are NOT the same names inside classB. How do I configure refB to
>
> tell
>
>>it that keyA references classB.secondKey and that keyB references
>>classB.firstKey or vica-versa. I am a little unclear on how to make the
>>distinction explicit. Any help will be appreciated.
>>
>>- Dan
>>
>><class-descriptor
>> class="mypackage.ClassA"
>> table="tableA"
>>
>> <field-descriptor
>> name="id"
>> column="id"
>> jdbc-type="INTEGER"
>> primarykey="true"
>> />
>> <field-descriptor
>> name="keyA"
>> column="keyA"
>> jdbc-type="INTEGER"
>> />
>> <field-descriptor
>> name="keyB"
>> column="keyB"
>> jdbc-type="INTEGER"
>> />
>> <reference-descriptor
>> name="refB"
>> class-ref="mypackage.ClassB"
>> >
>> <foreignkey field-ref="keyA"/>
>> <foreignkey field-ref="keyB"/>
>> </reference-descriptor>
>></class-descriptor>
>>
>>
>><class-descriptor
>> class="mypackage.ClassB"
>> table="tableB"
>>
>> <field-descriptor
>> name="firstKey"
>> column="firstKey"
>> jdbc-type="INTEGER"
>> primarykey="true"
>> />
>> <field-descriptor
>> name="secondKey"
>> column="secondKey"
>> jdbc-type="INTEGER"
>> primarykey="true"
>> />
>></class-descriptor>
>>
>>>__________________________________________________
>>>Daniel B. Brown | WELLS FARGO BANK MINNESOTA, N.A. |
>>>Software Architect | http://www.wellsfargo.com | MAC N2702-011 |
>>>9062 Old Annapolis Road | Columbia | MD | 21045-1951 |
>>> p: 410.884.2034 | f: 410.715.2325 |
>
> daniel.b.brown@wellsfargo.com
>
>>>|
>>>
>>
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>>
>
>
>
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Re: Compound Primary Key foreign key references
Posted by Jakob Braeuchi <jb...@gmx.ch>.
hi wayne,
Wayne Kidd wrote:
> Although this is, in fact the behavior of OJB, It seems that the right
> behavior should be to describe the referenced tables primary key in the
> sequence of the primary key definition. That is, if the primary key
> constraint gives the order as x,z,y then the referencing table should
> specify that its columns a,b,c refer to pk x,z,y with some syntax like
> <foreignkey field-ref="a" refers-to="x"/>
> <foreignkey field-ref="b" refers-to="z"/>
> <foreignkey field-ref="c" refers-to="y"/>
imo this would lead to less errors when using multicolumn-keys.
i opened a feature-request
http://nagoya.apache.org/scarab/issues/id/OJB249
jakob
>
> instead of assuming the sequence of the column definitions in the other
> table.
>
> Wayne
>
>
> Daniel.B.Brown@wellsfargo.com wrote:
>
>> My question was the later. I could not find the behavior in the
>> documentation.
>>
>> Thanks,
>>
>> - Dan
>>
>> -----Original Message-----
>> From: Ron Gallagher [mailto:rgallagh@bellsouth.net]
>> Sent: Monday, August 18, 2003 9:53 AM
>> To: OJB Users List
>> Subject: Re: Compound Primary Key foreign key references
>>
>>
>> Dan --
>>
>> Are you asking this question because you've tried this configuration
>> and it
>> doesn't work, or are you just confused as to how OJB will handle this
>> situation? If the former, then please provide more info regarding the
>> problems you're having. If the latter, then here's my explanation...
>>
>> Anytime ojb encounters a reference-descriptor, it matches up the
>> foreignkey
>> elements, one for one, with the primary key field-descriptors in the
>> referenced class. This matching process pairs up foreignkey and
>> field-descriptor elements in the same order that they appear in the
>> repository. So, in your case, the property mypackage.ClassA::keyA
>> will be
>> matched up with the property mypackage.ClassB::firstKey, and the property
>> mypackage.ClassA::keyB will be matched up with the property
>> mypackage.ClassB::secondKey
>>
>> Ron Gallagher
>> Atlanta, GA
>> rongallagher@bellsouth.net
>>
>>
>>> From: Daniel.B.Brown@wellsfargo.com
>>> Date: 2003/08/18 Mon AM 09:01:37 EDT
>>> To: ojb-user@db.apache.org
>>> Subject: Compound Primary Key foreign key references
>>>
>>> All,
>>>
>>> From what I can tell, the repository.dtd is not sufficient to uniquely
>>> reference an object with a compound primary key. I think I must be
>>
>>
>> missing
>>
>>> something. In the contrived example below the foreign keys used to
>>> reference class B are keyA and keyB. Unfortunately, the names of
>>> keyA and
>>> keyB are NOT the same names inside classB. How do I configure refB to
>>
>>
>> tell
>>
>>> it that keyA references classB.secondKey and that keyB references
>>> classB.firstKey or vica-versa. I am a little unclear on how to make the
>>> distinction explicit. Any help will be appreciated.
>>>
>>> - Dan
>>>
>>> <class-descriptor class="mypackage.ClassA"
>>> table="tableA"
>>>
>>> <field-descriptor
>>> name="id"
>>> column="id"
>>> jdbc-type="INTEGER"
>>> primarykey="true"
>>> />
>>> <field-descriptor
>>> name="keyA"
>>> column="keyA"
>>> jdbc-type="INTEGER"
>>> />
>>> <field-descriptor
>>> name="keyB"
>>> column="keyB"
>>> jdbc-type="INTEGER"
>>> />
>>> <reference-descriptor
>>> name="refB"
>>> class-ref="mypackage.ClassB"
>>> >
>>> <foreignkey field-ref="keyA"/>
>>> <foreignkey field-ref="keyB"/>
>>> </reference-descriptor>
>>> </class-descriptor>
>>>
>>>
>>> <class-descriptor class="mypackage.ClassB"
>>> table="tableB"
>>>
>>> <field-descriptor
>>> name="firstKey"
>>> column="firstKey"
>>> jdbc-type="INTEGER"
>>> primarykey="true"
>>> />
>>> <field-descriptor
>>> name="secondKey"
>>> column="secondKey"
>>> jdbc-type="INTEGER"
>>> primarykey="true"
>>> />
>>> </class-descriptor>
>>>
>>>> __________________________________________________
>>>> Daniel B. Brown | WELLS FARGO BANK MINNESOTA, N.A. |
>>>> Software Architect | http://www.wellsfargo.com | MAC N2702-011 |
>>>> 9062 Old Annapolis Road | Columbia | MD | 21045-1951 | p:
>>>> 410.884.2034 | f: 410.715.2325 |
>>
>>
>> daniel.b.brown@wellsfargo.com
>>
>>>> |
>>>>
>>>
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>>> To unsubscribe, e-mail: ojb-user-unsubscribe@db.apache.org
>>> For additional commands, e-mail: ojb-user-help@db.apache.org
>>>
>>>
>>
>>
>>
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>
>
>
> ---------------------------------------------------------------------
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>
>
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