A Comparison of Data Models in BaaS (Backend-as-a-Service)

While Backed-as-a-Service (BaaS) – and their stepbrothers PaaS – offerings should sensibly support various domain-specific data models for the application they support, these services are inherently built on a ‘meta’ data model. This meta data model lays the constraints for all domain-specific data and should thus be an important consideration in selecting or not selecting a BaaS solution.

I have sifted through the documentation of five popular BaaS solutions and tried to uncover the fundamental model of data underlying these platforms. My findings are presented below.

In a Nutshell

All examined solution but Firebase have a ‘three-tier’ data model where similar JSON documents are aggregated in collections or classes, which allow the effective querying of these documents. These collections of JSON documents in turn are aggregated in databases or per application. Some solutions provide additional mechanisms for defining connections between JSON documents (Parse, usergrid). Firebase features the most unique model; where all data is stored in one very big, hierarchical JSON document.

Parse

Parse stores data internally as flat JSON Documents, called ParseObject, with have the restriction that keys must be alphanumeric strings. Parse automatically creates ‘classes’ for ParseObjects, grouping objects with similar properties. Classes and all objects associated to them belong to applications, which can be defined on the Parse web interface. In addition, Notably, Parse allows for various types of relationships between ParseObjects for one-to-many and many-to-many relationships.

Firebase

Firebase stores data as JSON documents. Essentially, a data store in Firebase is one large JSON document. Data stores are associated with subdomains such as <my store>.firebase.com.

Kinvey

Fundamentally, Kinvey stores data as collections and entities. Entities are essentially JSON documents. Collections belong to applications. Internally, data is stored in a MongoDB cluster.

Apache usergrid_

The Apache usergrid_ documentation did not make it easy to find out about the data model underlying the platform. I think the data is primarily stored as JSON documents named entities on the platform. These in turn (I think) are stored in collections. Collections themselves belong to applications. Notably, Apache usergrid has some support for graph-like data as relationships between entities. Internally, Apache usergrid is based on Cassandara and provides good support for relational/SQL type queries.

BaasBox

Data in BaasBox is stored as JSON documents called documents. These documents are grouped in collections. Collections are ultimately stored in databases. Since every BaasBox server represents one application, databases belong to the application configured for the server.

References

Parse

ParseObject JavaDoc

Parse JavaDoc

Parse Documentation – Data & Security

Firebase

Firebase – How It Works

Firebase – Understanding Data

Kinvey

A backend’s representation inside Kinvey

Android – Data Store

Apache usergrid_

Entity.java in usergrid Java client library

Apache usergrid Documentation

BaasBox

BaasDocument JavaDoc

BaasBox Documentation – Database Management

UML Diagrams created with creately.com.

 

 

 

 

Force Android Studio to Update Maven Snapshot Dependencies

Problem

You are using Gradle to build your Android Studio project and you have linked Maven SNAPSHOT modules.

When you build your project, Gradle/Android Studio does not grab the latest version of the SNAPSHOT module but instead uses a cached version.

Solution

Add the following to your build.gradle:

configurations.all {

resolutionStrategy {

cacheChangingModulesFor 0, ‘seconds’

}

}

References

Gradle DSL Documentation – Resolution Strategy

Gradle Documentation Chapter 50, Section 50.9.22 Refresh

Gradle Forum – Use latest version of changing module

Import GitHub project to Android Studio

Problem

You have an existing GitHub project and would like to import it to Android Studio.

Solution

Perform the following steps to import your project.

Step 1: Install git for Windows

It can be downloaded for free from git-scm.com.

Most settings available during the installation process should be compatible with Android studio. Just choose the settings you deem the most appropriate.

Step 2: Link git executable to Android Studio

Open Android Studio and got to Settings. In the Setting dialog open the page Version Control / Git. Here define the path to the git executable you have just installed.

Step 3: Get the Path to your Repository from Github

Go to the GitHub page and get the HTTPs path to your repository. For instance:

https://github.com/mxro/WallOfTheWiseAndroid.git

Step 4: Import the Git project to Android Studio

Go to Android Studio and go to Menu / VCS / Checkout from Version Control / Git

Paste the HTTPS path you obtained from GitHub in the previous step and click on [Clone].

Provide your GitHub username and password.

Now the project should be imported to Android Studio and you should be able to commit and push future changes back to GitHub.

References

Android Studio Git Tutorial (Part 1) « Wii’s Blog

github – How to clone a remote git repository with Android Studio? – Stack Overflow

Setup Android Developer Studio | devroyal.de

Setting Up eclipse Luna with Maven for Android

As of August 2014, don’t even try this.

Officially, the Google Eclipse plugin supports Eclipse 4.4 (Luna) at present. However, in order to be able to create projects which are both Maven projects and Android projects you will need to install the m2e-android plugin. This currently does not support eclipse Luna. Probably, if you create a new Android project based on the archetype suggested by the m2e-android plugin, you might get errors such as:

  • …R cannot be resolved to a variable
  • Plugin execution not covered by lifecycle configuration: com.jayway.maven.plugins.android.generation2:android-maven-plugin:3.8.2:generate-sources (execution: default-generate-sources, phase: generate-sources)
  • Project configurator “me.gladwell.eclipse.m2e.android.androidDevelopmentToolsProjectConfigurator” is not available. To enable full functionality, install the project configurator and run Maven->Update Project Configuration.
  • Plugin execution not covered by lifecycle configuration: com.jayway.maven.plugins.android.generation2:android-maven-plugin:3.8.2:proguard (execution: default-proguard, phase: process-classes)

My recommendation is to use Android Studio.

You can easily add Maven dependencies to projects in Android Studio. Just locate the ‘build.gradle’ file in your application directory and add a compile dependency.