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Diffstat (limited to 'activerecord/lib/active_record/querying.rb')
-rw-r--r-- | activerecord/lib/active_record/querying.rb | 69 |
1 files changed, 69 insertions, 0 deletions
diff --git a/activerecord/lib/active_record/querying.rb b/activerecord/lib/active_record/querying.rb new file mode 100644 index 0000000000..4d8283bcff --- /dev/null +++ b/activerecord/lib/active_record/querying.rb @@ -0,0 +1,69 @@ +require 'active_support/core_ext/module/delegation' +require 'active_support/deprecation' + +module ActiveRecord + module Querying + delegate :find, :take, :take!, :first, :first!, :last, :last!, :all, :exists?, :any?, :many?, :to => :scoped + delegate :first_or_create, :first_or_create!, :first_or_initialize, :to => :scoped + delegate :find_by, :find_by!, :to => :scoped + delegate :destroy, :destroy_all, :delete, :delete_all, :update, :update_all, :to => :scoped + delegate :find_each, :find_in_batches, :to => :scoped + delegate :select, :group, :order, :except, :reorder, :limit, :offset, :joins, + :where, :preload, :eager_load, :includes, :from, :lock, :readonly, + :having, :create_with, :uniq, :references, :none, :to => :scoped + delegate :count, :average, :minimum, :maximum, :sum, :calculate, :pluck, :ids, :to => :scoped + + # Executes a custom SQL query against your database and returns all the results. The results will + # be returned as an array with columns requested encapsulated as attributes of the model you call + # this method from. If you call <tt>Product.find_by_sql</tt> then the results will be returned in + # a Product object with the attributes you specified in the SQL query. + # + # If you call a complicated SQL query which spans multiple tables the columns specified by the + # SELECT will be attributes of the model, whether or not they are columns of the corresponding + # table. + # + # The +sql+ parameter is a full SQL query as a string. It will be called as is, there will be + # no database agnostic conversions performed. This should be a last resort because using, for example, + # MySQL specific terms will lock you to using that particular database engine or require you to + # change your call if you switch engines. + # + # ==== Examples + # # A simple SQL query spanning multiple tables + # Post.find_by_sql "SELECT p.title, c.author FROM posts p, comments c WHERE p.id = c.post_id" + # > [#<Post:0x36bff9c @attributes={"title"=>"Ruby Meetup", "first_name"=>"Quentin"}>, ...] + # + # # You can use the same string replacement techniques as you can with ActiveRecord#find + # Post.find_by_sql ["SELECT title FROM posts WHERE author = ? AND created > ?", author_id, start_date] + # > [#<Post:0x36bff9c @attributes={"title"=>"The Cheap Man Buys Twice"}>, ...] + def find_by_sql(sql, binds = []) + logging_query_plan do + result_set = connection.select_all(sanitize_sql(sql), "#{name} Load", binds) + column_types = {} + + if result_set.respond_to? :column_types + column_types = result_set.column_types + else + ActiveSupport::Deprecation.warn "the object returned from `select_all` must respond to `column_types`" + end + + result_set.map { |record| instantiate(record, column_types) } + end + end + + # Returns the result of an SQL statement that should only include a COUNT(*) in the SELECT part. + # The use of this method should be restricted to complicated SQL queries that can't be executed + # using the ActiveRecord::Calculations class methods. Look into those before using this. + # + # ==== Parameters + # + # * +sql+ - An SQL statement which should return a count query from the database, see the example below. + # + # ==== Examples + # + # Product.count_by_sql "SELECT COUNT(*) FROM sales s, customers c WHERE s.customer_id = c.id" + def count_by_sql(sql) + sql = sanitize_conditions(sql) + connection.select_value(sql, "#{name} Count").to_i + end + end +end |