Hi Joe,
If you have a smaller dataset, you can avoid all the nasty JDBC stuff and achieve the goal using:
public NSArray<YourEntity> entities() { NSArray<YourEntity> entities = EOUtilities.objectsForEntityNamed(session().defaultEditingContext(), YourEntity.ENTITY_NAME); return YourEntity.DATE_COLUMN.dot("month").eq(2).filtered(entities); // I've used 2 (February) to filter the records. DATE_COLUMN is ERXKey }
Even if you have comparatively large dataset then you can do something as follows to do some memory optimization:
public NSArray<YourEntity> entities() { NSArray<YourEntity> entities = new NSMutableArray<YourEntity>(); NSArray<NSDictionary> rows = EOUtilities.rawRowsWithQualifierFormat(session().defaultEditingContext(), YourEntity.ENTITY_NAME, null, null); for(NSDictionary row : YourEntity.DATE_COLUMN.dot("month").eq(2).filtered(rows)) { // I've used 2 (February) to filter the records. DATE_COLUMN is ERXKey entities.add((YourEntity) EOUtilities.objectFromRawRow(session().defaultEditingContext(), YourEntity.ENTITY_NAME, row)); } return entities; }
Farrukh
On 2010-06-02, at 2:18 AM, Joe Kramer wrote: Hi Chuck,
Thanks for the response. Generally I avoid "non trivial" things as much as possible because I'm lazy...oops... I mean keenly focused on efficiency (that sounds better). But I think in this case the SQL approach may be worth it. In looking at the EOSQLQualifier docs I see that it is deprecated. It looks like using EOFetchSpecification.setHints() should do the trick in this case. Thanks for weighing in!
Regards,
Joe On Tue, Jun 1, 2010 at 3:53 PM, Chuck Hill <email@hidden> wrote:
On Jun 1, 2010, at 3:30 PM, Joe Kramer wrote:
Hi all,
I may be barking up the wrong tree here, but I wanted someone to confirm that for me. I have a simple Person EO with a NSTimestamp attribute for birthdate. I'm wondering if it is possible to create a qualifier to get all the people whose birthday is in a particular month (May, for example). The year doesn't matter so I can't do a simple ">" or "<". If this isn't possible (or efficient) I can change the data model to capture the birth month separately. Then I can just set the month programatically when a new person is created and use that value as the qualifier. Just curious what others think.
select extract(MONTH from col_name) from table_name;
So you could write a custom qualifier to do this. Generally, writing qualifiers ranks as "non trivial". I don't know of an existing qualifier that you can use. Depending on your needs, SQL might be the way to go. See EOSQLQualifier JavaDocs.
Chuck
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Chuck Hill Senior Consultant / VP Development
Practical WebObjects - for developers who want to increase their overall knowledge of WebObjects or who are trying to solve specific problems.
http://www.global-village.net/products/practical_webobjects
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