I was looking at DataMapper, which appeared at first glance to use the ActiveRecord ORM pattern. Other people said that it uses the DataMapper and/or the Domain Object pattern. What is the difference between those patterns? ...
Given a simple statement, such as: <statement id="SelectProducts" resultMap="???"> SELECT * FROM Products </statement> Is it possible to get a list of dictionary objects where the keys are the column names? ie. var list = Mapper.QueryForList<IDictionary<string,string>>("SelectProducts", null); IDictionary<string, string> dict = li...
have you re-factored from an Active Record to a Data Mapper pattern? what conditions prompted the switch? i'm primarily interested in web based applications, but would like to know the challenges that accompany such a move in any environment. ...
Is there a way of reusing the same resultMap multiple times in a single query. For example, suppose I have a "foo" resultMap: <resultMap id="foo" class="Foo"> <result property="Bar" column="bar" /> </resultMap> Is there a way to define another resultMap that reuses the above for different columns? Something like... <resultMap id="...
Up until now I've been using Active records in all my c# database driven applications. But now my application requires my persistence code being split from my business objects. I have read a lot of posts regarding Martin Fowler's data mapping pattern, but my knowledge of this pattern is still very limited. Let's use the following examp...
When implementing the DataMapper pattern, should the class model that I implement in the DataMapper package more closely resemble the domain model or the data model? ...
Can someone please derive a concrete example from the following: http://www.urdalen.com/blog/?p=210 ..that shows how to deal with one-to-many and many-to-many relationships? I've emailed the author some time ago but received no reply. I like his idea, but can't figure out how to implement it beyond simple single table relations. Not...
I'm using couchdbx v. 0.8.1 and datamapper 0.9.8. I've written a few simple views, copied some from other examples. If I query the views with a browser they return id's. If I query them using datamapper in ruby I get no id's. I've googled for days, been on IRC and looked through the couch and datamapper google groups. I've tried downgrad...
Hi, I'm building a PHP application using the data mapper pattern to separate my DB from the domain objects. I have a mapper class that returns Site objects based on data from the DB and accepts existing Site objects to be saved back to the DB. My problem is that in the system one (and only one) of all the sites has to be marked as the ...
Hi, I'm using the data mapper pattern in a PHP app I'm developing and have a question. At present, you request a Site object with a specific ID and the mapper will lookup the row, create an object and return it. However, if you do this again for the same Site you end up with two different objects with identical data. eg.: $mapper = new ...
Hi, I'm building an app in PHP and I'm using the data mapper pattern for my DB access. I was considering using the Observer pattern to have all my mappers observe the entities they create, so that they can automatically save any changes back to the database without me having to parse them back manually. I was just wondering if this was...
This regards the ruby ORM library DataMapper. This wiki describes how to use the in_memory adapter for DataMapper. The proper database adapters saves an incrementing, unique id on each model instance - in_memory doesn't seem to do that as shown by the following snippet: require 'rubygems' require 'dm-core' DataMapper.setup(:in_memory,...
I would like to know if the other similar open source solutions in .NET world, especially for 2.0 framework ...
I'm using Merb and DataMapper with a MySQL db. I want to access the database name, user, and password from a Rake task for my Merb app. I guess I could YAML.load() the the database.yml, but that seems ugly. Any ideas? ...
I have been utilizing the Fowler patterns for domain models with a Data Mapper and have run into some confusion on how to implement the creation portion of CRUD. I can't utilize existing ORM technologies as the underlying data sources are custom systems. The area that’s troubling me is how to call the underling ORM when I need to create ...
I am trying to use Datamapper in a Rails app as an alternative to ActiveRecord. I've followed the various setup instructions and have Datamapper working in my app. But one of the first things I noticed that no longer works is this: <%= f.error_messages %> I believe this is tied to an ActiveRecord helper - is there an alternative w...
I have a line in my routes.rb to map my Album model as a resource: map.resources :albums However, using Datamapper in place of ActiveRecord in Rails, why would this line: format.html { redirect_to(@album) } cause a redirect to: albums/%23<Album:0x72d452c> instead of: albums/1 In case further context is needed, my full crea...
Im trying to select random datasets with DataMapper, but seems like there is no such function support. For example, i have set of data: +-------------------+ | ID | Name | Value | +-------------------+ | 1 | T1 | 123 | | 2 | T2 | 456 | | 3 | T3 | 789 | | 4 | T4 | 101 | | ----------------- | | N | Tn | value | ...
I have no idea how I would set up a BerkelyDB database in a Ruby or Rails project. Does anyone have any experience configuring one, that they could talk about? Maybe using ActiveRecord or Datamapper? ...
Hello, im a beginner with DataMapper ORM, so i have question about complex querying. First, here is simplified data objects: class User property :id, Serial property :login, String has n, :actions end class Item property :id, Serial property :title has n, :actions has n, :users, :through => :actions end ...