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From "Marc.Boudreau" <Marc.Boudr...@ca.ibm.com>
Subject Re: Multibyte characters on SQL Server and Sybase
Date Fri, 08 Jan 2010 19:00:33 GMT

No, the problem is that code can be run on a variety of database platforms
like DB2, SQL Server, Oracle, etc...
So if I use @Column(columnDefinition="NVARCHAR(256)"), it will only work on
SQL Server and Sybase, because the other database platforms don't recognize
the NVARCHAR type.


Craig L Russell wrote:
> 
> Hi,
> 
> On Jan 8, 2010, at 7:53 AM, Marc Boudreau wrote:
> 
>>
>>
>> Currently, OpenJPA maps String fields to VARCHAR on SQLServer and  
>> Sybase.
>> There doesn't appear to be a way to cause a String field to be  
>> mapped to
>> NVARCHAR other than by using the @Column annotation and settings its
>> columnDefinition to "NVARCHAR".
> 
> What is the objection to using this technique on the columns that you  
> want to hold national use characters? It seems this use case is  
> exactly suited to this feature.
> 
>> At the same time, blindly using NVARCHAR
>> for all String fields is too costly in terms of storage space on the
>> database.  It ends up limiting the maximum size of the column (less
>> characters can fit because more bytes are used to store them).
>>
>> Unfortunately, the applications we write are required to be database
>> neutral because we support multiple vendors.
>>
>> I'd like to start a discussion on this matter.  Here are a couple of  
>> points
>> to lead us off...
>>   What's the severity of this missing functionality?
>>   Could an OpenJPA specific annotation be introduced to allow the  
>> mapping
>>   tool to use NVARCHAR instead of VARCHAR?.
> 
> Is the problem that the OpenJPA mapping tool doesn't support the  
> standard columnDefinition annotation in the way you want it to?
> 
> Craig
> 
>>
>>
>>
>> Marc Boudreau
>> Software Developer
>> IBM Cognos Content Manager
>> marc.boudreau@ca.ibm.com
>> Phone: 613-356-6412
> 
> Craig L Russell
> Architect, Sun Java Enterprise System http://db.apache.org/jdo
> 408 276-5638 mailto:Craig.Russell@sun.com
> P.S. A good JDO? O, Gasp!
> 
> 
> 

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