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Make calculations typecasty! (closes #4016) [Rick Olson]

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git-svn-id: http://svn-commit.rubyonrails.org/rails/trunk@3722 5ecf4fe2-1ee6-0310-87b1-e25e094e27de
This commit is contained in:
David Heinemeier Hansson
2006-03-01 16:25:14 +00:00
parent 32e0bebbb9
commit a8d085adf0
2 changed files with 76 additions and 26 deletions
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44
activerecord/lib/active_record/calculations.rb
View File

@@ -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

58
activerecord/test/calculations_test.rb
View File

@@ -27,22 +27,22 @@ class CalculationsTest < Test::Unit::TestCase
def test_should_group_by_field
c = Account.sum(:credit_limit, :group => :firm_id)
%w( 1 6 2 ).each { |firm_id| assert c.keys.include?(firm_id) }
[1,6,2].each { |firm_id| assert c.keys.include?(firm_id) }
end
def test_should_group_by_summed_field
c = Account.sum(:credit_limit, :group => :firm_id)
assert_equal 50, c['1']
assert_equal 105, c['6']
assert_equal 60, c['2']
assert_equal 50, c[1]
assert_equal 105, c[6]
assert_equal 60, c[2]
end
def test_should_group_by_summed_field_having_condition
c = Account.sum(:credit_limit, :group => :firm_id,
:having => 'sum(credit_limit) > 50')
assert_nil c['1']
assert_equal 105, c['6']
assert_equal 60, c['2']
assert_nil c[1]
assert_equal 105, c[6]
assert_equal 60, c[2]
end
def test_should_group_by_summed_association
@@ -59,25 +59,25 @@ class CalculationsTest < Test::Unit::TestCase
def test_should_group_by_summed_field_with_conditions
c = Account.sum(:credit_limit, :conditions => 'firm_id > 1',
:group => :firm_id)
assert_nil c['1']
assert_equal 105, c['6']
assert_equal 60, c['2']
assert_nil c[1]
assert_equal 105, c[6]
assert_equal 60, c[2]
end
def test_should_group_by_summed_field_with_conditions_and_having
c = Account.sum(:credit_limit, :conditions => 'firm_id > 1',
:group => :firm_id,
:having => 'sum(credit_limit) > 60')
assert_nil c['1']
assert_equal 105, c['6']
assert_nil c['2']
assert_nil c[1]
assert_equal 105, c[6]
assert_nil c[2]
end
def test_should_group_by_fields_with_table_alias
c = Account.sum(:credit_limit, :group => 'accounts.firm_id')
assert_equal 50, c['1']
assert_equal 105, c['6']
assert_equal 60, c['2']
assert_equal 50, c[1]
assert_equal 105, c[6]
assert_equal 60, c[2]
end
def test_should_calculate_with_invalid_field
@@ -87,9 +87,9 @@ class CalculationsTest < Test::Unit::TestCase
def test_should_calculate_grouped_with_invalid_field
c = Account.count(:all, :group => 'accounts.firm_id')
assert_equal 1, c['1']
assert_equal 2, c['6']
assert_equal 1, c['2']
assert_equal 1, c[1]
assert_equal 2, c[6]
assert_equal 1, c[2]
end
def test_should_calculate_grouped_association_with_invalid_field
@@ -135,4 +135,24 @@ class CalculationsTest < Test::Unit::TestCase
assert_nil c['Leetsoft']
assert_equal 8, c['Jadedpixel']
end
def test_should_reject_invalid_options
assert_nothing_raised do
[:count, :sum].each do |func|
# empty options are valid
Company.send(:validate_calculation_options, func)
# these options are valid for all calculations
[:select, :conditions, :joins, :order, :group, :having, :distinct].each do |opt|
Company.send(:validate_calculation_options, func, opt => true)
end
end
# :include is only valid on :count
Company.send(:validate_calculation_options, :count, :include => true)
end
assert_raises(ArgumentError) { Company.send(:validate_calculation_options, :sum, :include => :posts) }
assert_raises(ArgumentError) { Company.send(:validate_calculation_options, :sum, :foo => :bar) }
assert_raises(ArgumentError) { Company.send(:validate_calculation_options, :count, :foo => :bar) }
end
end