Skip to main content

NoSQL Data Modelling

Recently in one of the project we planned to use some NoSQL  Document database. One of the reasons we though document database would be a great fit was that we could get started without setting up any DB schema and start shoving entities into the document database.
Nothing can be further from the truth. Data modeling is as essential and as fundamental an exercise for NoSQL stores as it is for RDBMS. It is just that the concepts are different as compared to RDBMS where normalization\de-normalization provide some guidance. In my pursuit to understand how to model data for a document database i came across some great reference material that i want to share here.

I believe this is enough content for one to have a decent understanding on the topic and get going with the real modeling.

Comments

bryan said…
I would clarify to this extent: DATA modeling is about the data. DATABASE modeling is about storing the data for accuracy, flexibility, velocity, reliability and all those other system attributes (the "-ities") that comes with implementation choices.

DATA modeling strives to make the data understandable. DATABASE modeling strives to make the data accessible. Two very different objectives, and two very different tasks.

I agree that any implementation of a database will require some degree of thought and design -- unless, of course, you don't care about those "-ities".

I once placed a wastebasket full of discarded printouts and scrap paper onto a table, pointed to it, and said "This is a database. Not a very good one, because finding the data in it is inefficient and unreliable and sometimes the data you find is wrong, or the data you're looking for is missing. But this wastebasket full of paper is a database. Our goal, as database modelers and designers is to improve on this."

So it is with every innovation that comes along. Does it improve on the last version of our wastebasket? And was that just by accident, or did you think about it first? Thinking about it is "modeling".

Popular posts from this blog

Caching Images downloaded from web on Windows Phone Isolated storage

I was helping on a Windows Phone application where the requirement was to cache the images the phone downloads on the isolated storage for offline viewing.
I wanted a solution which was simple and as transparent as possible. While researching I found  someone wrote a Silverlight converter for loading images from isolated storage. Taking that as a base I created a converted which can
Load image from web (http + https), and persist it to isolated storage.In case of network connectivity issues can load the same image from isolated storage. It does that by mapping the http url to a isolated storage location.In case the network is down and the image is neither there in cache, loads a default image, passed as parameter to converter.Here is the gist for the implementation.


To use the converter
Import the name space.Declare the converter as resource.Set the Image Source Property to use this converter like this 

AngularJS Model - ViewModel

Recently Robin Ward did a comparison between AngularJS and Ember (both the post and the comments are interesting read). One of the complaint that Robin had that AngularJS does not provide any specialized model class. As described in the blog

There is no standard Model base class, nor is there a component or interface in AngularJS that defines what a model is supposed to be.
What that means is that anything defined on $scope can acts as model, as this sample on the blog describes




For some (like me) this is the flexibility where as for others who want a more structural approach this is a nuisance.AngularJS does not even provide any definite guidelines around how the model should be actually designed to be effective with AngularJS

This leads to what we call as $scope pollution. We define multitude of properties on the $scope object and managing it becomes difficult.  Looking at the code one cannot tell what is the actual model and what properties are just to support UI logic.

Model Desig…