diff options
Diffstat (limited to 'activerecord/lib/active_record/calculations.rb')
| -rw-r--r-- | activerecord/lib/active_record/calculations.rb | 173 |
1 files changed, 0 insertions, 173 deletions
diff --git a/activerecord/lib/active_record/calculations.rb b/activerecord/lib/active_record/calculations.rb deleted file mode 100644 index 8a44dc7df1..0000000000 --- a/activerecord/lib/active_record/calculations.rb +++ /dev/null @@ -1,173 +0,0 @@ -module ActiveRecord - module Calculations #:nodoc: - extend ActiveSupport::Concern - - CALCULATIONS_OPTIONS = [:conditions, :joins, :order, :select, :group, :having, :distinct, :limit, :offset, :include, :from] - - module ClassMethods - # Count operates using three different approaches. - # - # * Count all: By not passing any parameters to count, it will return a count of all the rows for the model. - # * Count using column: By passing a column name to count, it will return a count of all the rows for the model with supplied column present - # * Count using options will find the row count matched by the options used. - # - # The third approach, count using options, accepts an option hash as the only parameter. The options are: - # - # * <tt>:conditions</tt>: An SQL fragment like "administrator = 1" or [ "user_name = ?", username ]. See conditions in the intro to ActiveRecord::Base. - # * <tt>:joins</tt>: Either an SQL fragment for additional joins like "LEFT JOIN comments ON comments.post_id = id" (rarely needed) - # or named associations in the same form used for the <tt>:include</tt> option, which will perform an INNER JOIN on the associated table(s). - # If the value is a string, then the records will be returned read-only since they will have attributes that do not correspond to the table's columns. - # Pass <tt>:readonly => false</tt> to override. - # * <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 of 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) ... - # * <tt>:from</tt> - By default, this is the table name of the class, but can be changed to an alternate table name (or even the name - # of a database view). - # - # Examples for counting all: - # Person.count # returns the total count of all people - # - # Examples for counting by column: - # Person.count(:age) # returns the total count of all people whose age is present in database - # - # Examples for count with options: - # Person.count(:conditions => "age > 26") - # Person.count(:conditions => "age > 26 AND job.salary > 60000", :include => :job) # because of the named association, it finds the DISTINCT count using LEFT OUTER JOIN. - # Person.count(:conditions => "age > 26 AND job.salary > 60000", :joins => "LEFT JOIN jobs on jobs.person_id = person.id") # finds the number of rows matching the conditions and joins. - # Person.count('id', :conditions => "age > 26") # Performs a COUNT(id) - # Person.count(:all, :conditions => "age > 26") # Performs a COUNT(*) (:all is an alias for '*') - # - # Note: <tt>Person.count(:all)</tt> will not work because it will use <tt>:all</tt> as the condition. Use Person.count instead. - def count(*args) - case args.size - when 0 - construct_calculation_arel.count - when 1 - if args[0].is_a?(Hash) - options = args[0] - distinct = options.has_key?(:distinct) ? options.delete(:distinct) : false - construct_calculation_arel(options).count(options[:select], :distinct => distinct) - else - construct_calculation_arel.count(args[0]) - end - when 2 - column_name, options = args - distinct = options.has_key?(:distinct) ? options.delete(:distinct) : false - construct_calculation_arel(options).count(column_name, :distinct => distinct) - else - raise ArgumentError, "Unexpected parameters passed to count(): #{args.inspect}" - end - rescue ThrowResult - 0 - end - - # Calculates the average value on a given column. The value is returned as - # a float, or +nil+ if there's no row. See +calculate+ for examples with - # options. - # - # Person.average('age') # => 35.8 - def average(column_name, options = {}) - calculate(:average, column_name, options) - end - - # Calculates the minimum value on a given column. The value is returned - # with the same data type of the column, or +nil+ if there's no row. See - # +calculate+ for examples with options. - # - # Person.minimum('age') # => 7 - def minimum(column_name, options = {}) - calculate(:minimum, column_name, options) - end - - # Calculates the maximum value on a given column. The value is returned - # with the same data type of the column, or +nil+ if there's no row. See - # +calculate+ for examples with options. - # - # Person.maximum('age') # => 93 - def maximum(column_name, options = {}) - calculate(:maximum, column_name, options) - end - - # Calculates the sum of values on a given column. The value is returned - # with the same data type of the column, 0 if there's no row. See - # +calculate+ for examples with options. - # - # Person.sum('age') # => 4562 - def sum(column_name, options = {}) - calculate(:sum, column_name, options) - end - - # This calculates aggregate values in the given column. Methods for count, sum, average, minimum, and maximum have been added as shortcuts. - # Options such as <tt>:conditions</tt>, <tt>:order</tt>, <tt>:group</tt>, <tt>:having</tt>, and <tt>:joins</tt> can be passed to customize the query. - # - # There are two basic forms of output: - # * Single aggregate value: The single value is type cast to Fixnum for COUNT, Float for AVG, and the given column's type for everything else. - # * Grouped values: This returns an ordered hash of the values and groups them by the <tt>:group</tt> option. It takes either a column name, or the name - # of a belongs_to association. - # - # values = Person.maximum(:age, :group => 'last_name') - # puts values["Drake"] - # => 43 - # - # drake = Family.find_by_last_name('Drake') - # values = Person.maximum(:age, :group => :family) # Person belongs_to :family - # puts values[drake] - # => 43 - # - # values.each do |family, max_age| - # ... - # end - # - # Options: - # * <tt>:conditions</tt> - An SQL fragment like "administrator = 1" or [ "user_name = ?", username ]. See conditions in the intro to ActiveRecord::Base. - # * <tt>:include</tt>: Eager loading, see Associations for details. Since calculations don't load anything, the purpose of this is to access fields on joined tables in your conditions, order, or group clauses. - # * <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 - # Person.sum("2 * age") - def calculate(operation, column_name, options = {}) - construct_calculation_arel(options).calculate(operation, column_name, options.slice(:distinct)) - rescue ThrowResult - 0 - end - - private - def validate_calculation_options(options = {}) - options.assert_valid_keys(CALCULATIONS_OPTIONS) - end - - def construct_calculation_arel(options = {}) - validate_calculation_options(options) - options = options.except(:distinct) - - merge_with_includes = current_scoped_methods ? current_scoped_methods.includes_values : [] - includes = (merge_with_includes + Array.wrap(options[:include])).uniq - - if includes.any? - merge_with_joins = current_scoped_methods ? current_scoped_methods.joins_values : [] - joins = (merge_with_joins + Array.wrap(options[:joins])).uniq - join_dependency = ActiveRecord::Associations::ClassMethods::JoinDependency.new(self, includes, construct_join(joins)) - construct_finder_arel_with_included_associations(options, join_dependency) - else - scoped.apply_finder_options(options) - end - end - - end - end -end |