1 files changed, 37 insertions, 6 deletions
diff --git a/activerecord/lib/active_record/connection_adapters/abstract_adapter.rb b/activerecord/lib/active_record/connection_adapters/abstract_adapter.rb
index f205d77ddb..202187a047 100644
--- a/activerecord/lib/active_record/connection_adapters/abstract_adapter.rb
+++ b/activerecord/lib/active_record/connection_adapters/abstract_adapter.rb
@@ -120,6 +120,7 @@ module ActiveRecord
         @quoted_column_names, @quoted_table_names = {}, {}
         @prevent_writes = false
         @visitor = arel_visitor
+        @statements = build_statement_pool
         @lock = ActiveSupport::Concurrency::LoadInterlockAwareMonitor.new
 
         if self.class.type_cast_config_to_boolean(config.fetch(:prepared_statements) { true })
@@ -387,6 +388,22 @@ module ActiveRecord
         false
       end
 
+      def supports_insert_returning?
+        false
+      end
+
+      def supports_insert_on_duplicate_skip?
+        false
+      end
+
+      def supports_insert_on_duplicate_update?
+        false
+      end
+
+      def supports_insert_conflict_target?
+        false
+      end
+
       # This is meant to be implemented by the adapters that support extensions
       def disable_extension(name)
       end
@@ -476,11 +493,9 @@ module ActiveRecord
         # this should be overridden by concrete adapters
       end
 
-      ###
-      # Clear any caching the database adapter may be doing, for example
-      # clearing the prepared statement cache. This is database specific.
+      # Clear any caching the database adapter may be doing.
       def clear_cache!
-        # this should be overridden by concrete adapters
+        @lock.synchronize { @statements.clear } if @statements
       end
 
       # Returns true if its required to reload the connection between requests for development mode.
@@ -506,8 +521,8 @@ module ActiveRecord
         @connection
       end
 
-      def default_uniqueness_comparison(attribute, value) # :nodoc:
-        case_sensitive_comparison(attribute, value)
+      def default_uniqueness_comparison(attribute, value, klass) # :nodoc:
+        attribute.eq(value)
       end
 
       def case_sensitive_comparison(attribute, value) # :nodoc:
@@ -542,6 +557,19 @@ module ActiveRecord
         index.using.nil?
       end
 
+      # Called by ActiveRecord::InsertAll,
+      # Passed an instance of ActiveRecord::InsertAll::Builder,
+      # This method implements standard bulk inserts for all databases, but
+      # should be overridden by adapters to implement common features with
+      # non-standard syntax like handling duplicates or returning values.
+      def build_insert_sql(insert) # :nodoc:
+        if insert.skip_duplicates? || insert.update_duplicates?
+          raise NotImplementedError, "#{self.class} should define `build_insert_sql` to implement adapter-specific logic for handling duplicates during INSERT"
+        end
+
+        "INSERT #{insert.into} #{insert.values_list}"
+      end
+
       private
         def check_version
         end
@@ -689,6 +717,9 @@ module ActiveRecord
         def arel_visitor
           Arel::Visitors::ToSql.new(self)
         end
+
+        def build_statement_pool
+        end
     end
   end
 end