Stack Overflow
Stack Overflow

Questions tagged [datamapper]

Architectural pattern for separating application logic from storage.

Objects and relational databases have different mechanisms for structuring data.

The Data Mapper is a layer of software that separates the in-memory objects from the database. Its responsibility is to transfer data between the two and also to isolate them from each other. With Data Mapper the in-memory objects needn't know even that there's a database present; they need no SQL interface code, and certainly no knowledge of the database schema.

Pattern definition: http://martinfowler.com/eaaCatalog/dataMapper.html

1134 questions
5
votes
2 answers

Use DataMapper instead of ActiveRecord

DataMapper idea is definitely better than ActiveRecord. It has one API for a variety of data stores, including RDBMS and NoSQL stores. DataMapper is much smarter then ActiveRecord. It has "Strategic Eager Loading". This feature single-handedly…
Alexander Paramonov
  • 1,441
  • 14
  • 24
5
votes
3 answers

Codeigniter Datamapper ORM php 7 static issue

When I upgraded my server to php7 codeigniter and in particular datamapper ORM gives me this error... Message: Accessing static property DataMapper::$config as non static Filename: libraries/datamapper.php Line Number: 6474 the function in…
galipmedia
  • 77
  • 5
5
votes
2 answers

Rails 3: ActiveRecord vs. DataMapper (vs. ???) for Legacy MySQL Databases

Which ORM is best to use with a new Rails 3 app against a legacy MySQL 5.1 database? I do not expect to ever run a migration against this database (though the schema may change from time to time), but I will certainly be writing to it.
Mark Richman
  • 28,948
  • 25
  • 99
  • 159
5
votes
1 answer

Undefined method auto_upgrade! when pushing Sinatra/DataMapper app to Heroku

Does anybody know the magic incantation required to get a Sinatra application that uses DataMapper up and running on Heroku's Bamboo stack? The Bamboo stack doesn't include any pre-installed system gems and no matter what combination of gems I try I…
John Topley
  • 113,588
  • 46
  • 195
  • 237
5
votes
2 answers

DataMapper: Create new record or update existing

Does DataMapper provide a convenient way to create a new record when none exists or update an existing one? I couldn't find anything in the API documentation. This is what I have at the moment which doesn't seem very elegant: foo = Foo.get(id) if…
John Topley
  • 113,588
  • 46
  • 195
  • 237
5
votes
1 answer

Is there active development going on IBatis.Net DataMapper?

Is there active development going on IBatis.Net DataMapper? Do they have version for .Net 3.5. I saw lots of activity on iBatis Java DataMapper as they are planning to release iBatis3 with annotation support. What is the status of its .Net…
Amitabh
  • 59,111
  • 42
  • 110
  • 159
5
votes
1 answer

LoadError: cannot load such file -- data_mapper Why?

I am working on a Sinatra application where I would like to use data_mapper & sqlite3. in app.rb I have: require 'sinatra' require 'data_mapper' in the console when I do $ gem list I get(list somewhat edited to reflect db gems: * LOCAL GEMS…
FierceScarf
  • 461
  • 1
  • 5
  • 17
5
votes
1 answer

How to load a one-to-many relationship in Data Mapper?

While I'll go for the Ghost pattern in a 1:1 relationship, I'm not sure if this is sufficient in a 1:n relationship. For example, when I load an Order object that may have a hundred Item objects, I would first assign NULL to the items property. The…
openfrog
  • 40,201
  • 65
  • 225
  • 373
5
votes
1 answer

Ruby Datamapper table inheritance with associations

I started learning Datamapper and what I liked about it was that I can write my models with real inheritance. Now I wonder, if it is possible to be more advanced about this: class Event include DataMapper::Resource property :id, Serial …
Debilski
  • 66,976
  • 12
  • 110
  • 133
5
votes
3 answers

Refactoring from ActiveRecord to DataMapper

Have you refactored from an ActiveRecord to a DataMapper 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.
Owen
  • 82,995
  • 21
  • 120
  • 115
5
votes
3 answers

Datamapper: report why I can't destroy record

I'm setting up my db model using datamapper and dm-contraints. I have two models which have a many to many relationship but when I try to destroy one, the only message I get is false. Is it possible to get datamapper to give me more feedback one…
Gerard
  • 4,818
  • 5
  • 51
  • 80
5
votes
2 answers

DataMapper SQLite Error when creating new database

I am new to Sinatra and I am trying to make a database using SQLite3 and Datamapper. I installed both gems and also the adaptor and then tried to execute this code in a file: #config require 'sinatra' require 'sinatra/contrib' if…
Amja
  • 1,315
  • 9
  • 25
5
votes
2 answers

Zend Framework: Models, Mappers; Default Fields in Mappers & Field Operations in Models?

I'm creating a simple ORM in Zend Framework, to roughly encapsulate a public library application, using the DbTable/Mapper/Model approach. I'm not sure if the way I'm doing my User-related classes is right, though, as I have some logic in…
Steve Griffiths
  • 76
  • 5
5
votes
5 answers

Why does DataMapper use mixins vs inheritance?

So I'm just curious about this: DataMapper uses a mixin for its Models class Post include DataMapper::Resource While active-record uses inheritance class Post < ActiveRecord::Base Does anyone know why DataMapper chose to do it that way (or why…
cloudhead
  • 15,253
  • 6
  • 42
  • 37
5
votes
3 answers

Rack::Lint::LintError: Status must be >=100 seen as integer

I am using the DataMapper gem with Sinatra and followed the tutorial here: http://net.tutsplus.com/tutorials/ruby/ruby-for-newbies-working-with-datamapper/ I am connecting to the database and migrating as such: DataMapper.setup :default,…
etayluz
  • 15,920
  • 23
  • 106
  • 151
1 2 3
…
75 76