similar to: When to use optimistic locking?

I understand that ActiveRecord supports the "optimistic offline lock"-pattern through magic fields (created_at, updated_at). However, a scaffolded CRUD-Controller doesn''t generate the necessary code to support this feature (the model state gets lost between two action calls). What is the best practice to prevent users from overwriting objects with outdated data ? --

Hi! Say we have a rails active-record-based model called "instance" which can have different states - STOPPED, RUNNING, STARTING_UP, SHUTTING_DOWN, etc... There is a method #start which changes the instance state to STARTING_UP only if it is STOPPED. def start if self.state == STOPPED self.state = STARTING_UP self.save ... end end As you understand if we have multiple

Hi, Is there a way to tell Rails that the magic field name for optimistic database locking is not lock_version? I have a legacy database where the optimistic locking field is named "version". Thanks, Phil -- Posted via http://www.ruby-forum.com/.

The error is caused by the save! method updating an object that another thread (most likely in taskomatic) already updated. In the case of this race condition, we retry saving. However, a proper fix would involve fixing the locking. --- src/db-omatic/db_omatic.rb | 23 ++++++++++++++++++++--- 1 files changed, 20 insertions(+), 3 deletions(-) diff --git a/src/db-omatic/db_omatic.rb

I''m working on an app that makes use of rails'' optimistic locking feature and seeing some possibilities for improvements. It seems a bit tedious to have to add :lock_version to forms wherever the model is used. You also have to "hack" around rails'' UJS feature to add it as a URL parameter when using remote: true, method: [:put, :patch, :post, :delete].

All, I''ve written a simple job/opportunity tracking database app via RoR. I have about 10 internal users. Sometimes 2 people will want to update the same record at more or less the same time and they collide. In particular user 1 may edit a record, then get distracted, and finally an hour later they click save. During that hour user 2 may have pulled up the record, edited it, and

Hi, IN one of my unit tests I get an ActiveRecord::StaleObjectError: Attempted to update a stale object object.save! in object I have apart from other stuff an after_save method, which calls object.assosication.update_attributes(...) If I remove that line from my code my tests succeeds. Unfortunetly, I do not understand why an update_attributes call can generate an StaleObjectError. Maybe

Hi all, I''ve searched the forumns, but I can''t seem to find an answer to this one. I''m having trouble getting optimistic locking (OL) to work in my app, even though all of the pieces are there: * table has lock_version column, with default of 0 (zero) * lock_version column is being incremented by the first update (but the second doesn''t catch it) *

Hi all I have a Model like this: class Member < ActiveRecord::Base attr_accessible :username, :email, :first_name, :last_name end I have created a scaffold using script/generate scaffold member members Using the URL localhost:3000/members/edit/1 I can edit all attributes, including created_at, lock_version etc.! But it should only show the attributes I listed in attr_accessible! What

there are some things on a scaffold that i would like to use without the whole thing. is it better to generate one and then cut it down to only what you''ll use? are all of the things in a scaffold available to just build by hand? for instance, i have a scaffold for my users. in the list action, it has @user_pages, so that you can put @user_pages.current.next or something like that -

Shouldn''t update_all be updating lock_version? As you can see from my console session below, it is upating the record (changed running attribute to true and returned 1 to show 1 recored was updated). But it did not increment lock_version. And optimistic locking is working correctly otherwise. As you can see below, lock version = 562 before and after the update_all call but it is

Has anyone had any luck using the CalendarHelper plugin at http://wiki.rubyonrails.com/rails/pages/CalendarHelper recently? I''m scratching my head over the following error when I look at any page in my application: NameError in CalendarController#index undefined local variable or method `date_format'' for #<CalendarController:0x24ccd4c> RAILS_ROOT:

Hello people, I''d like to detect whether an attribute of a model has vaildates_presence_of applied to it so I can automatically apply a mandatory (*) to the field...it doesn''t look easy...any ideas? Cheers, -- Dan Webb http://www.danwebb.net

Hello, to implement some some kind of optimistic locking, I want to build a view, where an object is displayed together with a link containing the data of the displayed object. My first try looked something like <%= object.object_discription %> <%= link_to "action", :action => "take_action", :data => object %> this won''t work because object is of

Hi, I found it a while ago, an add-on to Rails for supporting movable select boxes, but I searched through the wiki and the mailing list and couldnt find what I was looking for. I was hoping someone might know of or remember something about the project. Thanks, Dylan.

Hi all, I''m making an Amy Hoy style tip sheet PDF for the Prototype and Scriptaculous AJAX stuff, to be used with Rails. Are there other resources you would suggest besides the websites themselves (the previous thread about Highlight reminded me of this)? Is there a particular focus that would be helpful for such a document? Preferred fonts or colors? I must say, once you get

I am currently experiencing concurrency issues after moving from MySQL to SQLite. My original program worked fined using MySQL but is now returning "SQLite3::BusyException" errors. The same result happens whether or not I enable the allow_concurrency flag. If I do manually acquire a lock on the SQLite DB the problem would disapear, but I thought that rails was supposed to handle this

Hi, first of all I will apologize in advance for my presumably noobish question, but I''m only starting to learn Rails and am a little confused with all the changes in 2.0.1. There are as good as no tutorials out yet and the 2 or 3 screencasts I''ve seen deal with the creation of both the app and the database. Now my problem is that I already have a database with a fair amount of

Some of my earlier questions may have hinted ever so slightly in the direction that I''m trying to implement "enumerations". By an enumeration here I mean a class that has a fixed number of immutable instances, which in turn have essentially only a name and a position. Requirements I''ve tried to meet are - Enumeration instances should only be loaded once from the

I have several tables for enumerations. They all have the same content: id, name, position. I''d like to avoid the tedious work of defining a class for each one explicitly. Not least, in order to avoid clutter in the model directory. Here''s what I''ve come up with: class EnumRecord < ActiveRecord::Base def self.define_enums(*enums) enums.each do |spec|