Hello all. I need to develop an in-house real-time event analytics solution for our web application (e.g: mixpanel, chartbeat, kissmetrics like tool). We mainly use ruby on rails, Redis, MySql and JavaScript. The analytics solution must have an API and must be real-time. I've never done any API nor worked with real-time data. What te...
I'm working on a game (something like chess) where every move needs to be saved into a database per move. Since it's very important that both reads and writes are fast, and I don't need complex queries, I'm probably going to go with a NoSQL solution. Which one though? I'm thinking about MongoDB but will its durability be an issue? It'...
I am designing an ASP.NET MVC 2 application. Currently I am leveraging Entity Framework 4 with switchable SQLServer and MySQL datastores. A requirement recently surfaced for the application to allow user-defined models/entities to be manipulated. Now I'm unsure if a SQL/relational database is appropriate at all; instead of adding/removi...
Hi, I tried searching through on stackoverflow as well as googling around a lot, but am not able to find answers to my problem (I guess I'm searching for the wrong keywords / terms). We are in the process of building a recommendation engine, and while we are initially logging all user activity in custom logs (we use ruby / rails), we ne...
I have been reading documentation and watching screencasts specific to Mongo DB over the past few days and I am at a loss for when a solution like this would be better than a typical pg or mysql environment. Specifically, my question is under what circumstance (w/ use case would be nice) would you want to go the nosql route? Thanks! ...
NHydrate is a lesser-known ORM for .Net - I stumbled across it for the first time yesterday. They have a good amount of information on their Codeplex page, and a several videos that are also quite informative. After reading through the docs and watching some of the videos I feel very curious about this ORM. Model driven development, a...
Could I have a list of type of applications I should build on a sql database and a list of applications i should build on a nosql database? ...
Over vacation I read Pat Helland's "Life Beyond Transactions" (yes, vacation was that good :). To sum it up briefly, it advocates limiting the scope of transactions to a single entity and then using groups of "activities" that have the ability to update the entity or cancel a task anytime a change takes place that would make that task in...
I have a Python script that does something along the line of: def MyScript(input_filename1, input_filename2): return val; i.e. for every pair of input, I calculate some float value. Note that val is a simple double/float. Since this computation is very intensive, I will be running them across different processes (might be on the s...
Why aren't there many DDD stories that use newer nosql tools such as db4o and Cassandra for persistence. In my view, the effort involved in O/R mapping seems too high for the returned value. Being able to report right off the database is the main advantage I can see for my projects. On the other hand, db4o seems to almost be the ...
What are the major differences between MongoDB and CouchDB, and are there any other major NO-SQL database-servers out there worth mentioning? I know that CERN uses CouchDB somewhere in their LHC back-end; huge stamp of approval. What are MongoDB - and any other major servers' - references? Update One of the major selling points of Cou...
Why RDBMS? data integrity get quality results with SQL and prevent duplicates use SQL to access the data --> Easy. Many more Why Key-value pair? horizontally scalable Simple datasets - hashmap, associative arrays etc Easy to put() and get() Many more. So, is there some kind of wrapper available which binds with the "nosql" kind o...
I work on large database (hundreds of GB) and Mysql now gives me more or less satisfaction. I hesitate to cassandra on launch. What I want to know everything before, so this kind of DBMS NoSQL is supposed to be faster than MySQL? Several points: The change in the number of column on a row In Mysql, they must all be defined in advance...
More and more of the noSQL databases that are in the spotlight uses the master/slave pattern to provide "availability", but what it does (at least from my perspective) is creating the weak link in a chain that will break anytime. - Master goes down, slaves stops to function. It's a great way to handle big amounts of data and to even out...
Hi, I just wanted to know if there is a fundamental difference between hbase, cassandra, couchdb and monogodb ? In other words, are they all competing in the exact same market and trying to solve the exact same problems. Or they fit best in different scenarios? All this comes to the question, what should I chose when. Matter of taste? ...
I'm starting a MongoDB project just for kicks and as a chance to learn MongoDB/NoSQL schemas. It'll be a live chat app and the stack includes: Rails 3, Ruby 1.9.2, Devise, Mongoid/MongoDB, CarrierWave, Redis, JQuery. I'll be handling the live chat polling/message queueing separately. Not sure how yet, either Node.js, APE or custom Eve...
I am wondering how to use CouchDB's map/reduce with multiple parameters. For example, if I have teams that have players with ages and genders, I assume I would do this for my map function: "function(doc){ if(doc.team_name) { emit(doc.team_name, doc); } }" However, I am unsure how to write a reduce function to get the oldest m...
Is it possible to use wildcards in views in CouchDB? For example, lets say I have a database that has teams, ages of players, players' averages, and gender of players. However, the players' ages may not be known - they could be from the Dominican Republic or whatnot. So I want to use a view with a map function that can accept not havi...
There appears to be a myriad of NoSQL databases available these days: CouchDB MongoDB Cassandra Hadoop There's also a boundary between these tools and tools such as Redis that work as a memcached replacement. Without hand waving and throwing too many buzz words - my question is the following: How does one intelligently decide which...
Currently we are saving all SOAP requests to a log file (rolling, one per day). When I get a request about who did what, when, how often etc - then I need to resort to heavy duty text manipulation in order to extract that information. My idea was to save those SOAP requests to a database where I could perform some queries. A SOAP requ...