diff options
Diffstat (limited to 'activerecord/lib/active_record/calculations.rb')
| -rw-r--r-- | activerecord/lib/active_record/calculations.rb | 44 |
1 files changed, 37 insertions, 7 deletions
diff --git a/activerecord/lib/active_record/calculations.rb b/activerecord/lib/active_record/calculations.rb index 74fdec363f..f2194db5df 100644 --- a/activerecord/lib/active_record/calculations.rb +++ b/activerecord/lib/active_record/calculations.rb @@ -1,5 +1,6 @@ module ActiveRecord module Calculations + CALCULATIONS_OPTIONS = [:conditions, :joins, :order, :select, :group, :having, :distinct] def self.included(base) base.extend(ClassMethods) end @@ -19,6 +20,11 @@ module ActiveRecord # * <tt>:include</tt>: Named associations that should be loaded alongside using LEFT OUTER JOINs. The symbols named refer # to already defined associations. When using named associations count returns the number DISTINCT items for the model you're counting. # See eager loading under Associations. + # * <tt>:order</tt>: An SQL fragment like "created_at DESC, name" (really only used with GROUP BY calculations). + # * <tt>:group</tt>: An attribute name by which the result should be grouped. Uses the GROUP BY SQL-clause. + # * <tt>:select</tt>: By default, this is * as in SELECT * FROM, but can be changed if you for example want to do a join, but not + # include the joined columns. + # * <tt>:distinct</tt>: Set this to true to make this a distinct calculation, such as SELECT COUNT(DISTINCT posts.id) ... # # Examples for counting all: # Person.count # returns the total count of all people @@ -37,7 +43,6 @@ module ActiveRecord # Note: Person.count(:all) will not work because it will use :all as the condition. Use Person.count instead. def count(*args) options = {} - column_name = :all #For backwards compatibility, we need to handle both count(conditions=nil, joins=nil) or count(options={}). if args.size >= 0 and args.size <= 2 @@ -55,9 +60,8 @@ module ActiveRecord else raise(ArgumentError, "Unexpected parameters passed to count(*args): expected either count(conditions=nil, joins=nil) or count(options={})") end - - column_name = options[:select] if options[:select] - options[:include] ? count_with_associations(options) : calculate(:count, column_name, options) + + options[:include] ? count_with_associations(options) : calculate(:count, :all, options) end # Calculates average value on a given column. The value is returned as a float. See #calculate for examples with options. @@ -109,14 +113,26 @@ module ActiveRecord # ... # end # + # Options: + # * <tt>:conditions</tt>: An SQL fragment like "administrator = 1" or [ "user_name = ?", username ]. See conditions in the intro. + # * <tt>:joins</tt>: An SQL fragment for additional joins like "LEFT JOIN comments ON comments.post_id = id". (Rarely needed). + # The records will be returned read-only since they will have attributes that do not correspond to the table's columns. + # * <tt>:order</tt>: An SQL fragment like "created_at DESC, name" (really only used with GROUP BY calculations). + # * <tt>:group</tt>: An attribute name by which the result should be grouped. Uses the GROUP BY SQL-clause. + # * <tt>:select</tt>: By default, this is * as in SELECT * FROM, but can be changed if you for example want to do a join, but not + # include the joined columns. + # * <tt>:distinct</tt>: Set this to true to make this a distinct calculation, such as SELECT COUNT(DISTINCT posts.id) ... + # # Examples: # Person.calculate(:count, :all) # The same as Person.count # Person.average(:age) # SELECT AVG(age) FROM people... # Person.minimum(:age, :conditions => ['last_name != ?', 'Drake']) # Selects the minimum age for everyone with a last name other than 'Drake' # Person.minimum(:age, :having => 'min(age) > 17', :group => :last_name) # Selects the minimum age for any family without any minors def calculate(operation, column_name, options = {}) + validate_calculation_options(operation, options) + column_name = options[:select] if options[:select] column_name = '*' if column_name == :all - column = columns.detect { |c| c.name.to_s == column_name.to_s } + column = column_for column_name aggregate = select_aggregate(operation, column_name, options) aggregate_alias = column_alias_for(operation, column_name) if options[:group] @@ -149,6 +165,7 @@ module ActiveRecord associated = association && association.macro == :belongs_to # only count belongs_to associations group_field = (associated ? "#{options[:group]}_id" : options[:group]).to_s group_alias = column_alias_for(group_field) + group_column = column_for group_field sql = construct_calculation_sql(aggregate, aggregate_alias, options.merge(:group_field => group_field, :group_alias => group_alias)) calculated_data = connection.select_all(sql) @@ -159,13 +176,21 @@ module ActiveRecord end calculated_data.inject(OrderedHash.new) do |all, row| - key = associated ? key_records[row[group_alias].to_i] : row[group_alias] + key = associated ? key_records[row[group_alias].to_i] : type_cast_calculated_value(row[group_alias], group_column) value = row[aggregate_alias] all << [key, type_cast_calculated_value(value, column, operation)] end end private + def validate_calculation_options(operation, options = {}) + if operation.to_s == 'count' + options.assert_valid_keys(CALCULATIONS_OPTIONS + [:include]) + else + options.assert_valid_keys(CALCULATIONS_OPTIONS) + end + end + def select_aggregate(operation, column_name, options) "#{operation}(#{'DISTINCT ' if options[:distinct]}#{column_name})" end @@ -180,7 +205,12 @@ module ActiveRecord keys.join(' ').downcase.gsub(/\*/, 'all').gsub(/\W+/, ' ').strip.gsub(/ +/, '_') end - def type_cast_calculated_value(value, column, operation) + def column_for(field) + field_name = field.to_s.split('.').last + columns.detect { |c| c.name.to_s == field_name } + end + + def type_cast_calculated_value(value, column, operation = nil) operation = operation.to_s.downcase case operation when 'count' then value.to_i |