diff options
Diffstat (limited to 'activerecord/lib/active_record/calculations.rb')
| -rw-r--r-- | activerecord/lib/active_record/calculations.rb | 23 |
1 files changed, 13 insertions, 10 deletions
diff --git a/activerecord/lib/active_record/calculations.rb b/activerecord/lib/active_record/calculations.rb index 7f8af9421e..df73cee2f3 100644 --- a/activerecord/lib/active_record/calculations.rb +++ b/activerecord/lib/active_record/calculations.rb @@ -15,14 +15,17 @@ module ActiveRecord # 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. - # * <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>:joins</tt>: Either an SQL fragment for additional joins like "LEFT JOIN comments ON comments.post_id = id". (Rarely needed). + # or names associations in the same form used for the :include option. + # 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 :readonly => false to override. + # See adding joins for associations under Associations. # * <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. + # 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 + # * <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) ... # @@ -44,35 +47,35 @@ module ActiveRecord calculate(:count, *construct_count_options_from_args(*args)) end - # Calculates average value on a given column. The value is returned as a float. See #calculate for examples with options. + # Calculates the average value on a given column. The value is returned as a float. See #calculate for examples with options. # # Person.average('age') def average(column_name, options = {}) calculate(:avg, column_name, options) end - # Calculates the minimum value on a given column. The value is returned with the same data type of the column.. See #calculate for examples with options. + # Calculates the minimum value on a given column. The value is returned with the same data type of the column. See #calculate for examples with options. # # Person.minimum('age') def minimum(column_name, options = {}) calculate(:min, column_name, options) end - # Calculates the maximum value on a given column. The value is returned with the same data type of the column.. See #calculate for examples with options. + # Calculates the maximum value on a given column. The value is returned with the same data type of the column. See #calculate for examples with options. # # Person.maximum('age') def maximum(column_name, options = {}) calculate(:max, column_name, options) end - # Calculates the sum value on a given column. The value is returned with the same data type of the column.. See #calculate for examples with options. + # Calculates the sum of values on a given column. The value is returned with the same data type of the column. See #calculate for examples with options. # # Person.sum('age') 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. + # This calculates aggregate values in the given column. Methods for count, sum, average, minimum, and maximum have been added as shortcuts. # Options such as :conditions, :order, :group, :having, and :joins can be passed to customize the query. # # There are two basic forms of output: @@ -237,7 +240,7 @@ module ActiveRecord end # Converts a given key to the value that the database adapter returns as - # as a usable column name. + # a usable column name. # users.id #=> users_id # sum(id) #=> sum_id # count(distinct users.id) #=> count_distinct_users_id |