Does rails do a rollback if I use begin...rescue?

I've been experimenting with this. It seems like if your rescue catches the exception that would have caused the rollback, the part of the transaction that already happened gets committed. In my case, I want the database rolled back to the way it was before the transaction started, but I still want to handle the exception.

I ended up with this:

self.transaction do  first_operation  begin    operation_that_might_violate_db_constraint  rescue ActiveRecord::RecordNotUnique      #deal with the error      raise ActiveRecord::Rollback #force a rollback  endend

The raise ActiveRecord::Rollback part makes sure the transaction gets completely rolled back. Without it, the changes from first_operation would end up getting committed.

The ActiveRecord::Rollback is a special kind of exception that doesn't bubble above the level of the transaction, so you won't end up with an uncaught exception that renders the error page.

I'm not sure this is the gold-standard way of doing this, but it seems to work.

Rollback not be processed.

ex:

create_table "helps", :force => true do |t|    t.string   "title",                           :null => false    t.text     "content"end#Rails consoleHelp.transaction do  Help.create! title: "aaa"  begin    Help.create! content: "111"  rescue    p "create error."  end  Help.create! title: "bbb"end#get this>> "create error."Help.count>> 2

Just using begin...rescue isn't enough to rollback a transaction. You need to use:

ModelName.transaction do end

This is done explicitely on a call to save, so that all of your callbacks are executed together. What exceptions are you catching in your rescue block? What are you responding to? What kind of errors?