(off topic: this discussion is good to see, as I will be taking it into account on the metawhere rewrite)
So, since this thread and another are currently ongoing relating to complex queries and the handling of ARel predicates, I thought I’d make a quick announcement that the MetaWhere rewrite-in-progress for Rails 3.1 is up on GitHub and actively being worked on: GitHub - activerecord-hackery/meta_where at rewrite
Specifically as a result of this thread, I’ve made core extensions opt-in, and am adding block syntax for those Relation methods where it makes sense. Hopefully this will alleviate some of the Symbol extension gripes that came up here. For example:
SQL Functions:
Person.select{max(id).as(max_id)}
=> SELECT max(“people”.“id”) AS ‘max_id’ FROM “people”
ANDs and association mapping:
Person.joins(:comments).
where{name >> ‘bob’ & {comments => body >> ‘First post!’}}
=> SELECT “people”.* FROM “people”
INNER JOIN “comments” ON “comments”.“person_id” = “people”.“id”
WHERE ((“people”.“name” = ‘bob’ AND “comments”.“body” = ‘First post!’))
The same query with an OR:
Person.joins(:comments).
where{name >> ‘bob’ | {comments => body >> ‘First post!’}}
=> SELECT “people”.* FROM “people”
INNER JOIN “comments” ON “comments”.“person_id” = “people”.“id”
WHERE ((“people”.“name” = ‘bob’ OR “comments”.“body” = ‘First post!’))
Could also be written as:
Person.joins(:comments).
where{name.eq(‘bob’) | {comments => body.eq(‘First post!’)}}
You get the idea. I’m still tweaking the operators, not so sure about >> for eq.
Anyway, this is the last MetaWhere-related post I’ll make – I just thought it might give a plugin option to those people who are looking for a way to get at the ARel goodness in AR and don’t want to wait on something in core.
-Ernie
