Eager Loading DataMapper Associations

[Dan Kubb (dkubb)]

Hi Everyone,

I just figured I'd share this with the list, it's a way of Eager Loading DM associations by specifying what associations to load:

  https://gist.github.com/3100034

I'll probably gemify it soon, but I wanted to get it out early in case people want to hack on it and test it out.

-- 

Dan

[Till Schulte-Coerne]

Hi Dan,

thanks for sharing this.

There was a discussion about eager loading a while ago: https://gist.github.com/1244491

We took that code (provided by d11wtq), changed some details and ended up here:

https://gist.github.com/3162356

I guess hacking in the model's instance variables wasn't the best idea. But I really like the API (using the QueryPath and a method in DataMapper::Collection).

--

Till

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[Dan Kubb (dkubb)]

Hi Till,

thanks for sharing this.

There was a discussion about eager loading a while ago: https://gist.github.com/1244491

We took that code (provided by d11wtq), changed some details and ended up here:

https://gist.github.com/3162356

 

I guess hacking in the model's instance variables wasn't the best idea. But I really like the API (using the QueryPath and a method in DataMapper::Collection).

That's a beautiful API. I took those ideas and combined them with mine, and ended up improving my gist:

https://gist.github.com/3100034  

The one takes one or more query paths as arguments, and eager loads all the objects along each path. This is exactly what I was hoping to do, but I didn't expect it to be so simple ;)

My next step will be to make something that extends DataMapper::Collection with a method that wraps things up into something more convenient. I'm not sure yet if I'll name the method #preload, #eager_load or something else.

-- 

Dan

[Avdi Grimm]

Unrelated, but this reminds me... are there known issues with STI and lazy loading? I had an issue the other day where all the "child" attributes on STI subclasses came up as nil when used. Changing the iteration from:

sti_collection.each do |record|

  ...

end

to:

sti_collection.to_a.each do |record|

   ...

end

fixed it.

-- 

Dan

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Avdi Grimm
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