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From Andrus Adamchik <and...@objectstyle.org>
Subject Re: [jira] Updated: (CAY-1282) Use #result as optional directive for only few columns (not all)
Date Sun, 11 Oct 2009 14:21:12 GMT
Hi Evgeny,

As always, thanks for the patch. A few comments:

1. A refactoring suggestion: move the new static methods introduced in  
ColumnDescriptor to non-static methods of RowDescriptorBuilder.
2. In 3.0 unit test classes are using *Test suffix instead of *Tst,  
and also we no longer put @author tags in the code.

Both items above are minor, and I can change them myself. Here is one  
potentially bigger issue with the patch though:

3. The patch merges 2 strategies for creation of columns descriptor  
into one, that requires access to ResultSetMetadata. I am not sure  
that ResultSet.getMetaData() is a trivial operation for all JDBC  
drivers that we support. I suspect there may be overhead accessing  
this data at least on some DBs. While we can verify this theory, I am  
wondering if we should, as in most cases we control the query syntax  
and don't need to consult ResultSetMetadata at all.

So maybe preserve the flow in RowDescriptorBuilder, and use your  
strategy merging explicit and implicit column descriptors *only* when  
an optional metadata object is initialized?

Andrus



On Oct 9, 2009, at 2:08 PM, Evgeny Ryabitskiy (JIRA) wrote:

>
>     [ https://issues.apache.org/jira/browse/CAY-1282?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel

>  ]
>
> Evgeny Ryabitskiy updated CAY-1282:
> -----------------------------------
>
>    Attachment: CAY-1282-3.patch
>
> Done!
>
>> Use #result as optional directive for only few columns (not all)
>> ----------------------------------------------------------------
>>
>>                Key: CAY-1282
>>                URL: https://issues.apache.org/jira/browse/CAY-1282
>>            Project: Cayenne
>>         Issue Type: Improvement
>>         Components: Cayenne Core Library
>>   Affects Versions: 1.2.5, 2.0.5, 3.0
>>           Reporter: Evgeny Ryabitskiy
>>           Assignee: Andrus Adamchik
>>            Fix For: 3.0 beta 1
>>
>>        Attachments: CAY-1282-3.patch, CAY-1282-3.patch,  
>> CAY-1282-3.patch, CAY-1282-3.patch, CAY-1282-3.patch, CAY-1282.patch
>>
>>
>> Here is few queries to show the problem:
>> SELECT ARTIST_ID, ARTIST_NAME FROM ARTIST
>> - working properly
>> SELECT #result('ARTIST_ID' 'java.lang.Integer'),  
>> #result('ARTIST_NAME' 'java.lang.String') FROM ARTIST
>> - also working properly
>> SELECT ARTIST_ID,  #result('ARTIST_NAME' 'java.lang.String') FROM  
>> ARTIST
>> - first column is returned as null!!! Not nice...
>
> -- 
> This message is automatically generated by JIRA.
> -
> You can reply to this email to add a comment to the issue online.
>
>


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