Apple

My tables are setup as follows:

Pool----*>>Entry-----63>>Game-----2>TeamPopup

To do my processing, specifically I need the rows from the Entry table, the Game table and the TeamPopup table that are associated with a single pool via joins from the pool's entries to each entry's games to each game's teams.

To process 1 pool that has say 300 entries, each entry having 63 Games and each Game having 2 Teams, That's 63 rows from the Entry table, 18900 distinct rows from the Games table and 37800 distinct rows from the Teams table. My first question is, with a pool name in hand, how do I fashion the qualifier so that all the Pool's associated Game Rows and Team rows that I need for processing are batch fetched in?

If it helps, I currently process the data something like this (yes, my actual code is better structured, but this shows the inner workings of what's really running).

Pool currPool = Pool.fetchStandardPoolWithName(ec, poolName);

ListIterator<Entry> entryIter = pool.entries().listIterator();

Entry nextEntry;

while (entryIter.hasNext()) {

nextEntry = entryIter.next();

for (int regionIndex = 0; regionIndex < 4; regionIndex ++) {

for (int gameIndex = 0; gameIndex < 15; j++) {

EOQualifier gameQual = Game.GROUP.eq(regionIndex).and(Game.GAME.eq(gameIndex));

Game currentGame = nextEntry.games(gameQual).objectAtIndex(0);

EOQualifier selQual = TeamPopup.COMBO_INDEX.eq(currentGame.selectedItem());

int seedOfSelectedTeam = currentGame.teamPopups(selQual).lastObject().seed();

// Do stuff with the seed and retrieve other information about the teams and games

}

So in the end, my first questions is regarding:

First, create a fetch specification for the main EO that you wish to operate on and prep it for pulling out the primary key;

How do I create the fetch specification when I need to work on multiple related EOs at the same time?

On Mar 1, 2009, at 10:04 PM, Andrew Lindesay wrote:

Hello Jeff;

Fair enough. I will keep it simple...

First, create a fetch specification for the main EO that you wish to operate on and prep it for pulling out the primary key;

EOEntity fooE = EOModelGroup.globalModelGroup().entityNamed("Foo");

EOFetchSpecification fs = ...

fs.setFetchesRawRows(true);
fs.setRawRowKeyPaths(fooE.primaryKeyAttributeNames());

By doing this, you don't give EOF so much work to do ensuring the EO's you are working with are unique. OK so now fetch this into an NSArray...

NSArray rrs = null;

{

EOEditingContext ec = new EOEditingContext();

ec.lock();
try { rrs = ec.objectsWithFetchSpecification(); }
finally { ec.unlock(); }
}

...work through these raw rows 50 (as an example) at a time...

for(int i=0;i<rrs.count();i+=50)
{
NSMutableArray<EOQualifier> qs = new NSMutableArray<EOQualifier>();

for(int j=i;(j<(i+50)) && (j<rrs.count());j++)
{
EOGlobalID gid = fooE.globalIDForRow((NSDictionary) rrs.objectAtIndex(j));
qs.addObject(LEEOHelper.qualifierForGlobalID(gid)); <--- copy this method from LEWOStuff source.
}

EOEditingContext ec = new EOEditingContext();

ec.lock();

try
{
EOFetchSpecification fs = new EOFetchSpecification("Foo",new EOOrQualifier(qs),null);

...fetch those EO's and do some stuff with them...
}
finally { ec.unlock(); }
}

...hope this helps and post back to the list (CC me) if you are confused.

cheers.

Yes, I saw your post. However, I'm not an advanced EOF user, nor do I know SQL very well (it's one of the reason I like webobjects). That and the fact that any change I make needs to be working in a couple of weeks makes me want to save a change like you suggest for later when I've got more time to come up to speed and to test. Maybe it's not as hard as it sounds? Keep in mind that right now when you say "Load the list of EO's into memory to be processed as raw-rows with the PK in the raw rows." I have NO idea what you're talking about.

___
Andrew Lindesay
www.lindesay.co.nz

References:
	>Re: Memory Management (From: Jeff Schmitz <email@hidden>)
	>Re: Memory Management (From: Andrew Lindesay <email@hidden>)
	>Re: Memory Management (From: Jeff Schmitz <email@hidden>)
	>Re: Memory Management (From: Andrew Lindesay <email@hidden>)