On Wed, 2007-06-13 at 23:41 -0400, Guillaume Theoret wrote:
> On 6/13/07, Daevid Vincent <daevid@xxxxxxxxxx> wrote:
> >
> > <?= $employeeType[ $row['employee_type_id'] ] ?>
> >
> > I actually use this little optimizing trick as an interview question for
> > new hires. You'd be amazed at how many people don't think of this, as
> > obvious as it seems to me...
Yep, for small sets of id to name mappings where the set won't likely
change much I do the exact same thing. No need for a DB hit for
something like that.
> That's a neat trick, I'll try to keep it in mind. In our current setup
> we'd do something like:
>
> [pseudo]
>
> while($row)
> $employee = find::($row['employee_id']); // Return an Employee object
> echo $employee->getType()->getName();
>
> So here, when we created an employee object, it did a db hit and
> looked in the employees table. The type attribute for employee was
> just a ProxyType object (with an id that was stored as type_id in the
> employees table). When I tried to access the name the ProxyType did a
> db hit and replaced itself with a Type object that had all the columns
> of the types table as its attributes. If we needed to later access
> some other attribute of the employee's type, no db hit would be made
> since it's now loaded.
>
> In this case, if you're looping over all employees and outputting
> their type names you'd be doing nearly twice as many db hits with my
> method. Thanks for the tip.
When I'm avoiding JOIN and I need related data I usually do something
like the following:
<?php
$criteria = array
(
'offset' => $offset,
'limit' => $limit,
);
$posts = $postFactory->getMatches( $criteria );
$userIds = array();
foreach( array_keys( $posts ) as $postId )
{
$userId = $posts[$postId]->userId();
$userIds[$userId] = $userId;
}
$criteria = array
(
'userId' => $userIds,
);
$users = $userFactory->getMatches( $criteria );
?>
The getMatches() method when it encounters an array for the 'userId'
criteria entry will use an IN clause for the array of user IDs given. So
it takes two queries -- one to get the topics, one to get the user
information.
Cheers,
Rob.
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