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authorJon Leighton <j@jonathanleighton.com>2011-08-09 00:12:53 +0100
committerJon Leighton <j@jonathanleighton.com>2011-08-15 23:10:15 +0100
commit128d006242dae07edc65ad03e0e045adac0bbbf3 (patch)
treeb06e9eb308ba00e12bae7fdaf8cd277ead5b352f /activerecord/lib/active_record/connection_adapters
parent9482554f31f3ac7f941e6239890c60fcc01975e1 (diff)
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Support updates with joins. Fixes #522.
Diffstat (limited to 'activerecord/lib/active_record/connection_adapters')
-rw-r--r--activerecord/lib/active_record/connection_adapters/abstract/database_statements.rb9
-rw-r--r--activerecord/lib/active_record/connection_adapters/mysql2_adapter.rb4
-rw-r--r--activerecord/lib/active_record/connection_adapters/mysql_adapter.rb4
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: