Not sure why linkable is not working for you. Did you make sure to set 'type' => 'INNER' in the linkable definition for that model? That will filter records from the parent model according to the conditions in the association.
On Tuesday, July 22, 2014 10:57:14 AM UTC+2, David Yell wrote: > > *Synopsis* > Trying to select data from multiple related models explicitly is hard in > the framework due to it's focus on always providing a left join. Even with > Containable and Linkable it's not always possible, without a manual query, > to select records where their related record has a condition. Such as > selecting all Posts where a Tag is authored by User x. It seems odd to me > that the framework should return empty related model records or, if using > linkable not return all the related records. I am starting this thread to > discuss solutions, tips, tricks and techniques for achieving this > functionality as I do not feel that either Containable or Linkable > accurately cover this use-case. It may well be that case that some more > guidance is needed in the documentation for this specific type of query. > > *The problem* > You would like to select from primary model but only if related models > conditions are met. The primary model should only be included in the result > set if the related model conditions are met. With a single related model > this is quite easy using Linkable. However when you start trying to achieve > this across HABTM, hasManyThrough or two or three nested models the problem > grows in complexity. > > A few examples, might make things clearer. > > *Hotel hasMany HotelFeature belongsTo Feature* > You need to select hotels which have n number of specific features. The > hotel must have all of the features listed to be included in the dataset. > > *Post hasMany PostsTag belongsTo Tag belongsTo User* > You need to find all the posts which have tags created by a certain user. > > *Hotel belongsTo City belongsTo Province belongsTo Country* > You need to select all the cities in a country where there is a hotel. > > I'm sure there are some other use-cases, but these are the ones of the top > of my head. As you can see it's usually selecting a primary record where a > related record matches a certain condition, but where the related record is > a multiple. > > *Possible solutions* > This is where I am unsure. My SQL-fu is weak thanks to Cake's awesome ORM. > The only real thing that I can think of is either more enhancements to > Containable or Linkable really. However I am not sure how to approach such > a problem. I was told once in an interview that any more than five joins > will impact performance in MySQL (could be fiction), so obviously there is > a performance concern with highly normalised databases. Concerns which are > ignored by Containable with it's multiple queries across many models - a > solution which I think was devised to solve this problem. > > *Discussion* > The idea of the thread was to discuss potential solutions really. I wanted > to air my thoughts on a problem which I have hit many times with my current > project and have had to battle against. Usually using manual joins, but in > most cases I end up using Containable and filtering the data in the > front-end `foreach()` which isn't elegant, clever or clean. > > I'm sure this kind of issue will have been addressed with the new ORM in > 3.x, but I need to find a decent solution to this problem which will be > flexible enough to be beneficial to lots of different projects, and to > other Cake users. We are all taught to normalise, and it makes sense to do > so, but this issue keeps nagging at me and I'm finding it frustrating. I > don't feel that the framework is helping me solve such a problem. > > If you read to here, thanks, have a biscuit and share your thoughts. How > do you get around this issue? > -- Like Us on FaceBook https://www.facebook.com/CakePHP Find us on Twitter http://twitter.com/CakePHP --- You received this message because you are subscribed to the Google Groups "CakePHP" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To post to this group, send email to [email protected]. Visit this group at http://groups.google.com/group/cake-php. For more options, visit https://groups.google.com/d/optout.
