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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

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DataMapper: tag to key relationship?

I'm using the DataMapper component in MuleStudio. I want to transform data that I have in this format login.01 to something like this …
Narabhut
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DataMapper Adapter for MS SqlServer

I am new to Ruby on Rails. I am planning to use SQLServer as the database for my application. For ORM, i did some searching and it is recommended to use DataMapper over ActiveRecords. But i cannot find any adapter from DataMapper to use with…
Vinoth
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Where/when to implement some COUNT() statements in my MVC application

Ok so I have my CustomerMapper mapping my Customer domain object perfectly but today I was in the middle of some business logic in one of my domain objects which uses my Customer object and I realized I needed to have some sort of if(…
ibanore
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Data mapper - count objects uploaded on specific date

I am building a simple app and I want to show some simple statistics to admins. I want to know is it possible to get the array of counts of objects from database that were created on the same date using datamapper or do I have to manually go through…
Antonio Novoselnik
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Ruby DataMapper: How can I do pagination?

I am going to retrieve a list of objects. get "/todoitems/?" do debugger todo = Todolist.all todo.to_json end Is there example that can retrieve page by page? Many thanks.
TheOneTeam
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undefined method merge

merb datamapper seems to be broken. $ merb Loading init file from /home/kristian/workspace/ruby/nightly/config/init.rb Loading /home/kristian/workspace/ruby/nightly/config/environments/development.rb :size option is deprecated, use String with…
kristian nissen
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Laravel 4 with Data Mapper?

Does anyone know if Laravel has some sort of library/plugin or tweak to use Data Mapper or to make Active Record behave like Data Mapper?. I'm not a Laravel user,so perhaps Eloquent is using a mix of Active Record and Data Mapper and I'm not aware…
AZReed
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MyBatis - Mapper vs DAO

I am trying to get this answered, and found one comment in the MyBatis documentation: Usually MapperFactoryBean is preferred to this class, since it requires no extra code. But, this class(DAO) is useful if you need to do other non-MyBatis work…
Sandeep Jindal
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DataMapper behaving differently when Rails app is run as console and server

I have a Rails 3.1 app and I use DataMapper as ORM. I have following models (stripped): class Task include DataMapper::Resource belongs_to :group def project group && group.project end end class Group include DataMapper::Resource …
mspanc
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Reducing service config duplication with a custom service locator?

My app uses the data mapper pattern, so I have a number of mapper classes, which each needs an instance of the database adapter. So the factories section of my service config is filled with entries like this: 'UserMapper' => function($sm) { …
Tim Fountain
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Ruby/DataMapper: Problems with multiple many-to-many associations

I have implemented models for User-Group relationship, where one User can be a member and owner of one or more Groups and where one Group can have one or more owners and one or more members. Now, the problem is User.owned_groups returns only 1 Group…
draxxxeus
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Using data mapper inside another data mapper in Java?

I'm using the data mapper pattern in Java for accessing the database. Is it OK to call a mapper inside of another mapper? As far as I'm concerned, mappers should work on their own without a dependency on other mappers, but it seems that someone else…
ZimZim
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Datamapper does not save/update entry

I'm currently developing a quick little sinatra app, and I've managed to conquer authentication quite easily. However I cannot for the life of me get password changing to work. I'm using the code below with Datamapper, and although it reaches the…
Simon M
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data_mapper find number of rows

I can't find an answer for this elsewhere, so I'm asking here: How do I "SELECT COUNT" with data_mapper? What I've tried: MyClass.count MyClass.size MyClass.all.count MyClass.all.size What does work is: ids = [] MyClass.all.each do |class| ids…
Alfo
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Get associated records with Datamapper using Sinatra

I am currently working on a small backend, managing events with associated locations. Unfortunately, it's my first time i work with Ruby/Sinatra/Datamapper. After 3 hours trying to find a solution, i have to write this post. I have defined two…
ehlers
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