diff options
Diffstat (limited to 'activerecord/lib/active_record/connection_adapters')
3 files changed, 17 insertions, 0 deletions
diff --git a/activerecord/lib/active_record/connection_adapters/abstract/database_statements.rb b/activerecord/lib/active_record/connection_adapters/abstract/database_statements.rb index 2ae655e68d..7543d35d3b 100644 --- a/activerecord/lib/active_record/connection_adapters/abstract/database_statements.rb +++ b/activerecord/lib/active_record/connection_adapters/abstract/database_statements.rb @@ -306,6 +306,15 @@ module ActiveRecord end end + # The default strategy for an UPDATE with joins is to use a subquery. This doesn't work + # on mysql (even when aliasing the tables), but mysql allows using JOIN directly in + # an UPDATE statement, so in the mysql adapters we redefine this to do that. + def join_to_update(update, select) #:nodoc: + subselect = select.clone + subselect.ast.cores.last.projections = [update.ast.key] + update.wheres = [update.ast.key.in(subselect)] + end + protected # Returns an array of record hashes with the column names as keys and # column values as values. diff --git a/activerecord/lib/active_record/connection_adapters/mysql2_adapter.rb b/activerecord/lib/active_record/connection_adapters/mysql2_adapter.rb index 18fdfa29ec..c01a64e354 100644 --- a/activerecord/lib/active_record/connection_adapters/mysql2_adapter.rb +++ b/activerecord/lib/active_record/connection_adapters/mysql2_adapter.rb @@ -577,6 +577,10 @@ module ActiveRecord where_sql end + def join_to_update(update, select) #:nodoc: + update.table select.ast.cores.last.source + end + protected def quoted_columns_for_index(column_names, options = {}) length = options[:length] if options.is_a?(Hash) diff --git a/activerecord/lib/active_record/connection_adapters/mysql_adapter.rb b/activerecord/lib/active_record/connection_adapters/mysql_adapter.rb index 14b950dbb0..ea0970028c 100644 --- a/activerecord/lib/active_record/connection_adapters/mysql_adapter.rb +++ b/activerecord/lib/active_record/connection_adapters/mysql_adapter.rb @@ -491,6 +491,10 @@ module ActiveRecord execute("RELEASE SAVEPOINT #{current_savepoint_name}") end + def join_to_update(update, select) #:nodoc: + update.table select.ast.cores.last.source + end + # SCHEMA STATEMENTS ======================================== def structure_dump #:nodoc: |