OrientDB - Overview
OrientDB is an Open Source NoSQL Database Management System. NoSQL Database provides a mechanism for storing and retrieving NO-relation or NON-relational data that refers to data other than tabular data such as document data or graph data. NoSQL databases are increasingly used in Big Data and real-time web applications. NoSQL systems are also sometimes called "Not Only SQL" to emphasize that they may support SQL-like query languages.
OrientDB also belongs to the NoSQL family. OrientDB is a second generation Distributed Graph Database with the flexibility of Documents in one product with an open source of Apache 2 license. There were several NoSQL databases in the market before OrientDB, one of them being MongoDB.
MongoDB vs OrientDB
MongoDB and OrientDB contains many common features but the engines are fundamentally different. MongoDB is pure Document database and OrientDB is a hybrid Document with graph engine.
|Relationships||Uses the RDBMS JOINS to create relationship between entities. It has high runtime cost and does not scale when database scale increases.||Embeds and connects documents like relational database. It uses direct, super-fast links taken from graph database world.|
|Fetch Plan||Costly JOIN operations.||Easily returns complete graph with interconnected documents.|
|Transactions||Doesn’t support ACID transactions, but it supports atomic operations.||Supports ACID transactions as well as atomic operations.|
|Query language||Has its own language based on JSON.||Query language is built on SQL.|
|Indexes||Uses the B-Tree algorithm for all indexes.||Supports three different indexing algorithms so that the user can achieve best performance.|
|Storage engine||Uses memory mapping technique.||Uses the storage engine name LOCAL and PLOCAL.|
OrientDB is the first Multi-Model open source NoSQL DBMS that brings together the power of graphs and flexibility of documents into a scalable high-performance operational database.