Re: [Springframework-developer] New JDBC feature - named parameters

[Thomas R. <tho...@tr...>]

James,

I've been off for a few days so little progress on this feature  
recently - just pulled the code out of the main tree.  The code will  
make it's way back after 1.2.5 is out - might add it to the sandbox  
in the meantime.

I did not think of adding support for pulling data directly from a  
bean - but the more I think about it the more attractive this option  
seems.  There has to be some parts of Spring that can be reused for  
pulling property values from a bean :)

For the expanded list - I do use the placeholder/bind variable  
approach so no need to worry.  The primary issue will be problems  
with very long lists - different drivers/databases have different  
limits on how long the list can be.

Thomas

PS - I'm not insulted :)  It's always better to bring up issues while  
something is still being worked instead of afterwards.

On Sep 14, 2005, at 9:53 AM, James Estes wrote:

> http://opensource2.atlassian.com/projects/spring/browse/SPR-303
>
> Hey Thomas, I'm glad to see this getting some traction.  I have a few
> questions though.
>
> Will the implementation support pulling the values from a bean (where
> the names in the query match property names in the bean)?  The
> original argument against was to just use ibatis...but with what you
> have it is so close.  I'd probably need to (for the most part) map my
> bean to and from a hashmap for the execute calls.
>
> I'm going to be looking at the code soon, but my first reaction to the
> auto-expanding list was one of fear.  I'm sure it has been implemented
> optimally, but just to voice my fear:  does passing in a list as a
> value simply trigger a replacement of that value/marker with a comma
> separated list of other markers (?s)?  Or is it one that will replace
> the marker with a comma-separated list of the values.  If it is the
> former, the hit is not too bad...assuming most use cases are such that
> only a set number or combination winds up getting used (like between 3
> and 10).  And (in the case of Oracle) only that many statements are
> cached and all is well.  But if its the latter (replaced with
> comma-separated values) then every single call is unique...and the db
> (oracle anyway) will die (especially if this call is made frequently)
> because the statement cache will constantly be pushing out statements
> for these new ones that appear to be unique.
>
> Anyway I hope I'm not insulting you...I'm sure you know this, like I
> said, just voicing my initial gut-fear.
>
> Thanks again Thomas,
> James
>
> On 9/7/05, Thomas Risberg <tho...@tr...> wrote:
>
>> I added support for named parameters some days ago.  Here is an  
>> example:
>>
>>
>>    public List getPreferredBeer() {
>>     Map params = new HashMap(2);
>>     params.put("unwantedBrand", "Heineken");
>>     params.put("maxPrice", new BigDecimal(25.00));
>>     List l = getJdbcTemplate().queryForList(
>>       "select id, price, brand from beers " +
>>       "where price < :maxPrice and brand <> :unwantedBrand",
>>       params);
>>     return l;
>>   }
>>
>> I put together a PDF document that highlights additional usage -
>> http://www.springdeveloper.com/documents/spring-1_3-jdbc-example.pdf
>>
>> Take a recent snapshot for a spin and let me know if something is  
>> missing or
>> not working.  I'm still working on adding some additional tests.
>>
>> Thomas
>>
>>
>>
>
>
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