On Fri, Jan 15, 2010 at 8:42 AM, Dave B. [email protected]
wrote:
So unless I’m missing something, I can’t keep a live object.
It’s a rails app, and the controller will be pulling together a
“@results” variable, but will not necessarily know what kinds of stats
need to be pulled from it. That’s why i’d like to be able to do things
like “the number of people in this group are @results.size
and they spent @results.collect(&:spend).sum on your
product this year”.
I don’t really see the benefit of storing the template in the database,
but
here is what I came up with.
require ‘rubygems’
require ‘activerecord’
require ‘sqlite3’
require ‘erb’
db = SQLite3::Database.new( ‘store_and_execute_strings.db’ )
db.execute <<-__________________________________________________
CREATE TABLE IF NOT EXISTS reports (
id INTEGER PRIMARY KEY ASC AUTOINCREMENT,
title Text,
template TEXT
);
__________________________________________________
db.execute <<-__________________________________________________
CREATE TABLE IF NOT EXISTS groups (
id INTEGER PRIMARY KEY ASC AUTOINCREMENT,
name STRING
);
__________________________________________________
db.execute <<-__________________________________________________
CREATE TABLE IF NOT EXISTS people (
id INTEGER PRIMARY KEY ASC AUTOINCREMENT,
group_id INTEGER,
money_spent DOUBLE,
age INTEGER
);
__________________________________________________
documentation at
http://api.rubyonrails.org/classes/ActiveRecord/Base.html
for other (better, depending on your needs) documentation, see
http://guides.rubyonrails.org/active_record_querying.html
http://guides.rubyonrails.org/association_basics.html
http://guides.rubyonrails.org/activerecord_validations_callbacks.html
ActiveRecord::Base.establish_connection :adapter =>
‘sqlite3’ ,
:host =>
‘localhost’ ,
:database =>
‘store_and_execute_strings.db’ ,
:username =>
‘root’ ,
:password => ‘’
class Report < ActiveRecord::Base
def generate( &init )
dup.instance_eval {
instance_eval &init if init
ERB.new( template , 0 , “%<>” ).result( binding )
}
end
end
class Group < ActiveRecord::Base
has_many :people
end
class Person < ActiveRecord::Base
belongs_to :group
end
here is an example, as I understand your criteria
text_for_report = "the number of people in this group are <%=
@people.length
%> and they have spent "
"a total of $<%= @people.inject(0) { |sum,person|
sum+person.money_spent.to_f } %> "
“on your product this year”
Report.new( :template => text_for_report , :title => ‘Customer Summary’
).save
doctors = Group.new :name => ‘doctors’
doctors.save
(1…10).each do |num|
money , age = num , 20+num*5
doctors.people.build( :money_spent => money , :age => age ).save
end
customer_summary = Report.find_by_title ‘Customer Summary’
puts customer_summary.generate { @people =
doctors.people }
puts customer_summary.generate { @people = doctors.people.all
:conditions =>
‘money_spent <= 5’ }
puts customer_summary.generate { @people = doctors.people.all
:conditions =>
‘age < 40’ }