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From Rick Hillegas <Richard.Hille...@Sun.COM>
Subject Re: Creating User Types in Derby
Date Wed, 14 Nov 2007 04:06:23 GMT
Hi Samuel,

I agree with Dag that this issue is a little complicated and you may 
want to tackle something smaller first just to get familiar with the 
Derby codeline. The objects stored in system tables, which Dag 
mentioned, are a special kind of user defined type with a highly 
optimized storage representation. A good place to start is to grep the 
codeline for UserDefinedType. This will introduce you to a lot of 
compiler support for user types.

One wrinkle of this feature is that the community will want to agree on 
SQL standard syntax for declaring user types and for using them as 
column and argument types. You will want to take a look at part 2 of the 
2003 SQL standard, sections 4.7, 11.41, and 11.49--as well as part 13, 
sections 4.8, 9.4, and 9.7. Other sections are probably relevant but 
those would be a good start.

Regards,
-Rick

Dag H. Wanvik wrote:
> Samuel Morgan <samdeking@gmail.com> writes:
>
>   
>> Thanks Guys,
>>
>> I will register and see what I can do.. Id love to help or even start
>> developing it.. Im afraid I dont know where to start. Any suggestions?
>>     
>
> Great!
>
> For general information, have a look at:
>
> http://db.apache.org/derby/derby_comm.html
> http://wiki.apache.org/db-derby/ForNewDevelopers
>
> As for this particular issue, maybe Rick can offer some advice?
> Looking at how this is used internally in the system tables is
> probably a good start, e.g. in SYS.SYSCONGLOMERATES the column
> DESCRIPTOR has the type org.apache.derby.catalog.IndexDescriptor.
>
> http://db.apache.org/derby/docs/dev/ref/rrefsistabs38369.html
>
> It may be advisable to tackle some smaller issue first, so you know
> your way around a bit before you try to attack this issue. Your call :)
>
> Thanks,
> Dag
>   
>> Sam
>>
>>
>> Dag H. Wanvik wrote:
>>     
>>> Rick Hillegas <Richard.Hillegas@Sun.COM> writes:
>>>
>>>       
>>>> Samuel Morgan wrote:
>>>>         
>>>> Right now you can't declare custom types in Derby. This feature has
>>>> been requested before and is tracked by DERBY-651. So far no-one has
>>>> volunteered to work on this issue.
>>>>         
>>> You can vote for it, or even better, help us develop it :)
>>>
>>> http://issues.apache.org/jira/secure/ViewVoters!default.jspa?id=12325061
>>>
>>> Thanks,
>>> Dag
>>>
>>>
>>>       
>> -- 
>> View this message in context: http://www.nabble.com/Creating-User-Types-in-Derby-tf4776240.html#a13732800
>> Sent from the Apache Derby Developers mailing list archive at Nabble.com.
>>
>>
>>     
>
>   


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