[ANN] Slice and dice plugin

I’ve been playing around with some easier ways of specifying
conditions in active record, and have come up with a little plugin
that some may find useful. Currently active record finder and
calculations methods can take a :conditions option with a string or
array listing some sql conditions, eg:

Animals.find :first, :conditions => “name = ‘Tiger’”

My plugin enables simple conditions like this to be written without
any SQL at all, using a hash instead of an array or string:

Animals.find :first, :conditions => {:name => ‘Tiger’}

As well as simple equality conditions, other tests such as more than,
less than and contains can also be specified:

Animals.find :first, :conditions => {:name_starts_with => ‘Tig’}
Animals.find :all, :conditions => {:population_more_than => 1_000_000}

Conditions can be combined:

endangered_tigers = Animals.find :all, :conditions => {:name_contains
=> ‘Tiger’, :population_less_than => 10_000}

These conditions can also be used in calculations and scoped queries:

Animals.count :conditions => {:population_more_than => 1_000_000}

Animals.with_scope :find => {:conditions => {:name_contains => ‘Tiger’}}
do
Animals.find :all
end

Finally, here’s an simple way to use this plugin to add lots of data
slicing and dicing to any list actions you might have:

class AnimalController < ActiveController
def list
animal_conditions = params.dup.reject! {|k, v| [:action, :control
ler].include? k}
@animals = Animal.find :all, :conditions => animal_conditions
end
end

This allows urls such as
/animal/list?name_starts_with=T&population_less_than=1000

Please take a look, the code is available at
svn://rubyforge.org/var/svn/popdog/slice_and_dice/tags/REL-0.1

I’d welcome any comments or ideas on how to improve this (currently
very simple) plugin. I do have some planned extra features of my own,
so watch this space!

Tom

On Apr 22, 2006, at 7:24 AM, Tom W. wrote:

Tom

Hey Tom-

Just wanted to point you at my plugin called ez_where:


http://opensvn.csie.org/ezra/rails/plugins/dev/ez_where/

My plugin solves the same problems that slice and dice does but in a

different way. It allows you to use ruby operators instead of sql ops
and it allows find to take a block to define :conditions. It also
allows for nested sub conditions and stuff like that. Here’s a little
peak at what it can do:

@articles = Article.find_with_block(:all, :include => :author) do |
article, author|
article.title =~ “%Foo Title%”
author.any do
name == ‘Ezra’
name == ‘Fab’
end
end

This will do a find :all with:
:conditions => [“article.title LIKE ? AND
(authors.name = ? OR authors.name = ?)”,
“%Foo Title%”, “Ezra”, “Fab”]

Basically here is the breakdown of how we map ruby operators
to SQL operators:

foo == ‘bar’ #=> [“foo = ?”, ‘bar’]
foo =~ ‘%bar’ #=> [“foo LIKE ?”, ‘%bar’]
foo <=> (1…5) #=> [“foo BETWEEN ? AND ?”, 1, 5]
id === [1, 2, 3, 5, 8] #=> [“id IN(?)”, [1, 2, 3, 5, 8]]
<, >, >=, <= et all will just work like you expect.

There is also the ability to create the conditions in stages so
you can build up a query:

cond = Caboose::EZ::Condition.new do
foo == ‘bar’
baz <=> (1…5)
id === [1, 2, 3, 5, 8]
end

@result = Model.find(:all, :conditions=> cond.to_sql)
#=> [“foo = ? AND baz BETWEEN ? AND ? AND id IN (?)”,
“bar”, 1, 5, [1, 2, 3, 5, 8]]

There is some seriously fun metaprogramming going on in ez_where

that you might want to take a peek at :wink:

Cheers-
-Ezra

PS. the test cases are 700 lines long and serve as the best docs
right now. The tests exercise all the features of the plugin.

On Apr 22, 2006, at 2:27 PM, Craig W. wrote:

There is some seriously fun metaprogramming going on in ez_where that


You beat me to the punch as I was about the say the same thing…as
you know, I very much love ez_where and have made good usage of it.

I can’t figure out how to determine with version I have and whether I
should update it, nor can I tell when you update the plugin itself.

Craig

Craig-

ez_where is at revision 85 right now and hasn't changed in about a

month. I am working on an update for it with a few more niceties that
I will roll out soon and I will be sure to let you know.

Cheers-

Ezra

That’s really cool, Tom. I love how readable your queries are.

Duane J.
(canadaduane)
http://blog.inquirylabs.com/

On Sat, 2006-04-22 at 09:12 -0700, Ezra Z. wrote:

I’d welcome any comments or ideas on how to improve this (currently
Hey Tom-

Just wanted to point you at my plugin called ez_where:

http://brainspl.at/articles/2006/01/30/i-have-been-busy
http://opensvn.csie.org/ezra/rails/plugins/dev/ez_where/

now. The tests exercise all the features of the plugin.


You beat me to the punch as I was about the say the same thing…as you
know, I very much love ez_where and have made good usage of it.

I can’t figure out how to determine with version I have and whether I
should update it, nor can I tell when you update the plugin itself.

Craig

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