Your first Hadoop Map-Reduce Job

Introduction Hadoop Map-Reduce is a YARN-based system for parallel processing of large data sets. If you are new to hadoop, first visit here. In this article, I will help you quickly start with writing the simplest Map-Reduce job. This is a famous “Wordcount” MR job and the first one for 90% of the people (if not more).…

Composite Keys in Cassandra

Introduction A composite key consists of one or more primary key fields. Each field must be of data type supported by underlying data-store. In JPA (Java Persistence API), there are two ways of specifying composite keys: 1. Composite Primary Key: 2. Embedded Primary Key: Above Timeline entity is inspired from famous twissandra example. Starting 1.1 release, Cassandra supports…

Cross-datastore Persistence using Kundera

Introduction Kundera is a powerful JPA based object-datastore mapping library (ORM equivalent) for NoSQL databases. It significantly reduced programming effort required for performing CRUD operations in NoSQL databases. Kundera currently supports Cassandra, HBase, MongoDB and relational databases. Cross-datastore persistence is the latest additions to it feather. If your business objects are distributed across multiple databases,…

Data Model

Working with MongoDB using Kundera

Kundera – a JPA 2.0 (Java Persistence API) based ORM library was originally developed for Cassandra database. A support for Hbase was later added to it. Those who are new to Kundera, should read this to get a basic idea. For impatient ones – Get started with Kundera in 5 minutes! Kundera now supports MongoDB –…