http://p.caboo.se/141009
Here is a proof of concept that has 70% of the stated features
implemented. If you could test it, it'd be great.
On 19 янв, 20:53, Inviz <[EMAIL PROTECTED]> wrote:
> This is a proposal on automated query joiner.
>
> Let's assume we have 2 queries:
>
> user_query = User.select(:id, :login).filter{:name !=
> "guest"}.sort_by(:id.desc)
> group_query = Group.select(:id, :name).filter{:id !=
> 1}.sort_by(:id.asc)
>
> Let's say we want to fetch this all in one query. In current sequel
> implementation we do this:
>
> User.select(:user__id, :user__login, :group__id, :group__name).join(:groups,
> :user__group_id
> => :group__id).filter{:user__name != "guest" && :group__id !=
> 1}.order_by(:user__id.desc, :group__id.asc).sql
>
> => "SELECT user.`id`, user.`login`, group.`id`, group.`name` FROM
> users INNER JOIN groups ON (user.`group_id` = group.`id`) WHERE ((NOT
> (user.`name` = 'guest')) AND (NOT (group.`id` = 1))) ORDER BY
> user.`id` DESC, group.`id` ASC"
>
> Mess? Yes it is. Not much different from usual SQL. Not even shorter.
>
> Now, let's try this:
>
> user_query << [group_query, :user__group_id => :group__id]
> # << is for left join
> # >> is for right
>
> => "SELECT user.`id`, user.`login`, group.`id`, group.`name` FROM
> users INNER JOIN groups ON (user.`group_id` = group.`id`) WHERE ((NOT
> (user.`name` = 'guest')) AND (NOT (group.`id` = 1))) ORDER BY
> user.`id` DESC, group.`id` ASC"
>
> What it does is conjucts 2 already built query objects. Conjucts and
> automatically prefixes *select* statements. Conjucts orders and
> conditions.
>
> We can make it a little bit magical.
>
> imagine this:
> class User
> def group
> Group.select(:id => group_id)
> end
> end
>
> user_query << group_query #here we omit the JOIN conditions, sequel
> take it from "group" definition of User.
>
> Isn't that readable and cool? It even can use built in subsets
> feature!
> That's the bomb. And pretty easy to implement
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