diff options
Diffstat (limited to 'activerecord/lib/active_record/querying.rb')
| -rw-r--r-- | activerecord/lib/active_record/querying.rb | 19 |
1 files changed, 11 insertions, 8 deletions
diff --git a/activerecord/lib/active_record/querying.rb b/activerecord/lib/active_record/querying.rb index c84f3d0fbb..8c1b2e2be1 100644 --- a/activerecord/lib/active_record/querying.rb +++ b/activerecord/lib/active_record/querying.rb @@ -16,17 +16,17 @@ module ActiveRecord delegate :pluck, :pick, :ids, to: :all # 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 + # be returned as an array, with the requested columns encapsulated as attributes of the model you call + # this method from. For example, 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 + # 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 + # 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 + # database-specific terms will lock you into using that particular database engine, or require you to # change your call if you switch engines. # # # A simple SQL query spanning multiple tables @@ -40,7 +40,8 @@ module ActiveRecord def find_by_sql(sql, binds = [], preparable: nil, &block) result_set = connection.select_all(sanitize_sql(sql), "#{name} Load", binds, preparable: preparable) column_types = result_set.column_types.dup - columns_hash.each_key { |k| column_types.delete k } + cached_columns_hash = connection.schema_cache.columns_hash(table_name) + cached_columns_hash.each_key { |k| column_types.delete k } message_bus = ActiveSupport::Notifications.instrumenter payload = { @@ -60,7 +61,9 @@ module ActiveRecord # 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. + # using the ActiveRecord::Calculations class methods. Look into those before using this method, + # as it could lock you into a specific database engine or require a code change to switch + # database engines. # # Product.count_by_sql "SELECT COUNT(*) FROM sales s, customers c WHERE s.customer_id = c.id" # # => 12 |