File: README.rdoc

# README.rdoc

Path: | README.rdoc
Last Update: | Tue Aug 24 17:37:03 -0600 2010

dm-aggregates

###### =======

DataMapper plugin providing support for aggregates, functions on collections and datasets.

It provides the following functions:

## count

Count results (given the conditions)

     Friend.count # returns count of all friends
     Friend.count(:age.gt => 18) # returns count of all friends older then 18
     Friend.count(:conditions => [ 'gender = ?', 'female' ]) # returns count of all your female friends
     Friend.count(:address) # returns count of all friends with an address (NULL values are not included)
     Friend.count(:address, :age.gt => 18) # returns count of all friends with an address that are older then 18
     Friend.count(:address, :conditions => [ 'gender = ?', 'female' ]) # returns count of all your female friends with an address

## min

Get the lowest value of a property

     Friend.min(:age) # returns the age of the youngest friend
     Friend.min(:age, :conditions => [ 'gender = ?', 'female' ]) # returns the age of the youngest female friends

## max

Get the highest value of a property

     Friend.max(:age) # returns the age of the oldest friend
     Friend.max(:age, :conditions => [ 'gender = ?', 'female' ]) # returns the age of the oldest female friends

## avg

Get the average value of a property

     Friend.avg(:age) # returns the average age of friends
     Friend.avg(:age, :conditions => [ 'gender = ?', 'female' ]) # returns the average age of the female friends

## sum

Get the total value of a property

     Friend.sum(:age) # returns total age of all friends
     Friend.max(:age, :conditions => [ 'gender = ?', 'female' ]) # returns the total age of all female friends

[Validate]