Added new Base.find API and deprecated find_all, find_first. Added preliminary support for eager loading of associations

git-svn-id: http://svn-commit.rubyonrails.org/rails/trunk@1077 5ecf4fe2-1ee6-0310-87b1-e25e094e27de

4 files changed, 150 insertions, 73 deletions

diff --git a/activerecord/lib/active_record/associations.rb b/activerecord/lib/active_record/associations.rb
index 5bdc6247ff..fa3c28f7d4 100755
--- a/activerecord/lib/active_record/associations.rb
+++ b/activerecord/lib/active_record/associations.rb
@@ -19,7 +19,7 @@ module ActiveRecord
         instance_variable_set "@#{assoc.name}", nil
       end
     end
-
+    
     # Associations are a set of macro-like class methods for tying objects together through foreign keys. They express relationships like 
     # "Project has one Project Manager" or "Project belongs to a Portfolio". Each macro adds a number of methods to the class which are 
     # specialized according to the collection or association symbol and the options hash. It works much the same was as Ruby's own attr* 
@@ -617,6 +617,60 @@ module ActiveRecord
             end_eval
           end
         end
+
+
+        def find_with_associations(options = {})
+          reflections = [ options[:include] ].flatten.collect { |association| reflect_on_association(association) }
+          rows = connection.select_all(construct_finder_sql_with_included_associations(reflections), "#{name} Load Including Associations")
+          records = rows.collect { |row| instantiate(extract_record(table_name, row)) }.uniq
+
+          reflections.each do |reflection| 
+            records.each do |record|
+              case reflection.macro
+                when :has_many
+                  record.send(reflection.name).target = extract_association_for_record(record, rows, reflection)
+                when :has_one, :belongs_to
+                  record.send("#{reflection.name}=", extract_association_for_record(record, rows, reflection).first)
+              end
+            end
+          end
+          
+          return records
+        end
+
+        def construct_finder_sql_with_included_associations(reflections)
+          sql = "SELECT #{selected_columns(table_name, columns)}"
+          reflections.each { |reflection| sql << ", #{selected_columns(reflection.klass.table_name, reflection.klass.columns)}" }
+          sql << " FROM #{table_name} "
+          reflections.each do |reflection| 
+            sql << " LEFT JOIN #{reflection.klass.table_name} ON " +
+              "#{reflection.klass.table_name}.#{table_name.classify.foreign_key} = #{table_name}.#{primary_key}"
+          end
+          
+          return sanitize_sql(sql)
+        end
+
+        def extract_association_for_record(record, rows, reflection)
+          association = rows.collect do |row| 
+            if row["#{table_name}__#{primary_key}"] == record.id.to_s
+              reflection.klass.send(:instantiate, extract_record(reflection.klass.table_name, row))
+            end
+          end
+
+          return association.compact
+        end
+
+        def extract_record(table_name, row)
+          row.inject({}) do |record, pair|
+            prefix, column_name = pair.first.split("__")
+            record[column_name] = pair.last if prefix == table_name
+            record
+          end
+        end
+
+        def selected_columns(table_name, columns)
+          columns.collect { |column| "#{table_name}.#{column.name} as #{table_name}__#{column.name}" }.join(", ")
+        end
     end
   end
 end
diff --git a/activerecord/lib/active_record/associations/association_proxy.rb b/activerecord/lib/active_record/associations/association_proxy.rb
index e32519537b..caa896f826 100644
--- a/activerecord/lib/active_record/associations/association_proxy.rb
+++ b/activerecord/lib/active_record/associations/association_proxy.rb
@@ -31,6 +31,11 @@ module ActiveRecord
       def loaded?
         @loaded
       end
+      
+      def target=(t)
+        @target = t
+        @loaded = true
+      end
 
       protected
         def dependent?
diff --git a/activerecord/lib/active_record/base.rb b/activerecord/lib/active_record/base.rb
index 8d548ec8a2..70004ec458 100755
--- a/activerecord/lib/active_record/base.rb
+++ b/activerecord/lib/active_record/base.rb
@@ -1,4 +1,5 @@
 require 'yaml'
+require 'active_record/deprecated_finders'
 
 module ActiveRecord #:nodoc:
   class ActiveRecordError < StandardError #:nodoc:
@@ -301,77 +302,40 @@ module ActiveRecord #:nodoc:
       #
       # +RecordNotFound+ is raised if no record can be found.
       def find(*args)
-        # Return an Array if ids are passed in an Array.
-        expects_array = args.first.kind_of?(Array)
-
-        # Extract options hash from argument list.
         options = extract_options_from_args!(args)
-        conditions = " AND #{sanitize_sql(options[:conditions])}" if options[:conditions]
-
-        ids = args.flatten.compact.uniq
-        case ids.size
-
-          # Raise if no ids passed.
-          when 0
-            raise RecordNotFound, "Couldn't find #{name} without an ID#{conditions}"
-
-          # Find a single id.
-          when 1
-            unless result = find_first("#{primary_key} = #{sanitize(ids.first)}#{conditions}")
-              raise RecordNotFound, "Couldn't find #{name} with ID=#{ids.first}#{conditions}"
-            end
-
-            # Box result if expecting array.
-            expects_array ? [result] : result
 
-          # Find multiple ids.
+        case args.first
+          when :first
+            find(:all, options.merge({ :limit => 1 })).first
+          when :all
+            options[:include] ? find_with_associations(options) : find_by_sql(construct_finder_sql(options))
           else
-            ids_list = ids.map { |id| sanitize(id) }.join(',')
-            result   = find_all("#{primary_key} IN (#{ids_list})#{conditions}", primary_key)
-            if result.size == ids.size
-              result
-            else
-              raise RecordNotFound, "Couldn't find all #{name.pluralize} with IDs (#{ids_list})#{conditions}"
+            expects_array = args.first.kind_of?(Array)
+            conditions = " AND #{sanitize_sql(options[:conditions])}" if options[:conditions]
+
+            ids = args.flatten.compact.uniq
+            case ids.size
+              when 0
+                raise RecordNotFound, "Couldn't find #{name} without an ID#{conditions}"
+              when 1
+                if result = find(:first, options.merge({ :conditions => "#{primary_key} = #{sanitize(ids.first)}#{conditions}" }))
+                  return expects_array ? [ result ] : result
+                else
+                  raise RecordNotFound, "Couldn't find #{name} with ID=#{ids.first}#{conditions}"
+                end
+              else
+                # Find multiple ids
+                ids_list = ids.map { |id| sanitize(id) }.join(',')
+                result   = find(:all, options.merge({ :conditions => "#{primary_key} IN (#{ids_list})#{conditions}", :order => primary_key }))
+                if result.size == ids.size
+                  return result
+                else
+                  raise RecordNotFound, "Couldn't find all #{name.pluralize} with IDs (#{ids_list})#{conditions}"
+                end
             end
         end
       end
 
-      # Returns true if the given +id+ represents the primary key of a record in the database, false otherwise.
-      # Example:
-      #   Person.exists?(5)
-      def exists?(id)
-        !find_first("#{primary_key} = #{sanitize(id)}").nil? rescue false
-      end
-
-      # This method is deprecated in favor of find with the :conditions option.
-      # Works like find, but the record matching +id+ must also meet the +conditions+.
-      # +RecordNotFound+ is raised if no record can be found matching the +id+ or meeting the condition.
-      # Example:
-      #   Person.find_on_conditions 5, "first_name LIKE '%dav%' AND last_name = 'heinemeier'"
-      def find_on_conditions(ids, conditions)
-        find(ids, :conditions => conditions)
-      end
-
-      # Returns an array of all the objects that could be instantiated from the associated
-      # table in the database. The +conditions+ can be used to narrow the selection of objects (WHERE-part),
-      # such as by "color = 'red'", and arrangement of the selection can be done through +orderings+ (ORDER BY-part),
-      # such as by "last_name, first_name DESC". A maximum of returned objects and their offset can be specified in 
-      # +limit+ with either just a single integer as the limit or as an array with the first element as the limit, 
-      # the second as the offset. Examples:
-      #   Project.find_all "category = 'accounts'", "last_accessed DESC", 15
-      #   Project.find_all ["category = ?", category_name], "created ASC", [15, 20]
-      def find_all(conditions = nil, orderings = nil, limit = nil, joins = nil)
-        sql  = "SELECT * FROM #{table_name} " 
-        sql << "#{joins} " if joins
-        add_conditions!(sql, conditions)
-        sql << "ORDER BY #{orderings} " unless orderings.nil?
-
-        limit = sanitize_sql(limit) if limit.is_a? Array and limit.first.is_a? String
-        connection.add_limit!(sql, limit) if limit
-
-        find_by_sql(sql)
-      end
-  
       # Works like find_all, but requires a complete SQL string. Examples:
       #   Post.find_by_sql "SELECT p.*, c.author FROM posts p, comments c WHERE p.id = c.post_id"
       #   Post.find_by_sql ["SELECT * FROM posts WHERE author = ? AND created > ?", author_id, start_date]
@@ -379,15 +343,13 @@ module ActiveRecord #:nodoc:
         connection.select_all(sanitize_sql(sql), "#{name} Load").inject([]) { |objects, record| objects << instantiate(record) }
       end
       
-      # Returns the object for the first record responding to the conditions in +conditions+, 
-      # such as "group = 'master'". If more than one record is returned from the query, it's the first that'll
-      # be used to create the object. In such cases, it might be beneficial to also specify 
-      # +orderings+, like "income DESC, name", to control exactly which record is to be used. Example: 
-      #   Employee.find_first "income > 50000", "income DESC, name"
-      def find_first(conditions = nil, orderings = nil, joins = nil)
-        find_all(conditions, orderings, 1, joins).first
+      # Returns true if the given +id+ represents the primary key of a record in the database, false otherwise.
+      # Example:
+      #   Person.exists?(5)
+      def exists?(id)
+        !find_first("#{primary_key} = #{sanitize(id)}").nil? rescue false
       end
-    
+
       # Creates an object, instantly saves it as a record (if the validation permits it), and returns it. If the save
       # fail under validations, the unsaved object is still returned.
       def create(attributes = nil)
@@ -739,6 +701,21 @@ module ActiveRecord #:nodoc:
           self.name =~ /::/ ? self.name.scan(/(.*)::/).first.first + "::" + type_name : type_name
         end
 
+        def construct_finder_sql(options)
+          sql  = "SELECT * FROM #{table_name} " 
+          sql << "#{options[:joins]} " if options[:joins]
+          add_conditions!(sql, options[:conditions])
+          sql << "ORDER BY #{options[:order]} " if options[:order]
+
+          if options[:limit] && options[:offset]
+            connection.add_limit_with_offset!(sql, options[:limit].to_i, options[:offset].to_i)
+          elsif options[:limit]
+            connection.add_limit_without_offset!(sql, options[:limit].to_i)
+          end
+          
+          return sql
+        end
+
         # Adds a sanitized version of +conditions+ to the +sql+ string. Note that it's the passed +sql+ string is changed.
         def add_conditions!(sql, conditions)
           sql << "WHERE #{sanitize_sql(conditions)} " unless conditions.nil?
diff --git a/activerecord/lib/active_record/deprecated_finders.rb b/activerecord/lib/active_record/deprecated_finders.rb
new file mode 100644
index 0000000000..cdbba37085
--- /dev/null
+++ b/activerecord/lib/active_record/deprecated_finders.rb
@@ -0,0 +1,41 @@
+module ActiveRecord
+  class Base # :nodoc:
+    class << self
+      # This method is deprecated in favor of find with the :conditions option.
+      #
+      # Works like find, but the record matching +id+ must also meet the +conditions+.
+      # +RecordNotFound+ is raised if no record can be found matching the +id+ or meeting the condition.
+      # Example:
+      #   Person.find_on_conditions 5, "first_name LIKE '%dav%' AND last_name = 'heinemeier'"
+      def find_on_conditions(ids, conditions)
+        find(ids, :conditions => conditions)
+      end
+
+      # This method is deprecated in favor of find(:first, options).
+      #
+      # Returns the object for the first record responding to the conditions in +conditions+, 
+      # such as "group = 'master'". If more than one record is returned from the query, it's the first that'll
+      # be used to create the object. In such cases, it might be beneficial to also specify 
+      # +orderings+, like "income DESC, name", to control exactly which record is to be used. Example: 
+      #   Employee.find_first "income > 50000", "income DESC, name"
+      def find_first(conditions = nil, orderings = nil, joins = nil)
+        find(:first, :conditions => conditions, :order => orderings, :joins => joins)
+      end
+
+      # This method is deprecated in favor of find(:all, options).
+      #
+      # Returns an array of all the objects that could be instantiated from the associated
+      # table in the database. The +conditions+ can be used to narrow the selection of objects (WHERE-part),
+      # such as by "color = 'red'", and arrangement of the selection can be done through +orderings+ (ORDER BY-part),
+      # such as by "last_name, first_name DESC". A maximum of returned objects and their offset can be specified in 
+      # +limit+ with either just a single integer as the limit or as an array with the first element as the limit, 
+      # the second as the offset. Examples:
+      #   Project.find_all "category = 'accounts'", "last_accessed DESC", 15
+      #   Project.find_all ["category = ?", category_name], "created ASC", [15, 20]
+      def find_all(conditions = nil, orderings = nil, limit = nil, joins = nil)
+        limit, offset = limit.is_a?(Array) ? limit : [ limit, nil ]
+        find(:all, { :conditions => conditions, :order => orderings, :joins => joins, :limit => limit, :offset => offset})
+      end
+    end
+  end
+end
\ No newline at end of file