Titan Database is described as 'Titan is a scalable graph database optimized for storing and querying graphs containing hundreds of billions of vertices and edges distributed across a multi-machine cluster' and is an app in the Development category. There are more than 50 alternatives to Titan Database for a variety of platforms, including Linux, Windows, Mac, Online / Web-based and BSD. The best alternative is DBeaver, which is both free and Open Source. Other great apps like Titan Database are PostgreSQL (Free, Open Source), SQLite (Free, Open Source), MongoDB (Free) and MySQL Community Edition (Free, Open Source).
HSQLDB (Hyper Structured Query Language Database) is a relational database management system written in Java. It has a JDBC driver and supports a large subset of SQL-92 and SQL:2008 standards. It offers a fast, small (around 1300 kilobytes in version 2.
DB2 offers industry leading performance, scale, and reliability on your choice of platform from Linux to z/OS. DB2 supports storing XML and relational data and offers SQL PL and PL/SQL procedural languages.
RedisGraph is a property graph database module for Redis. It is the first graph database to use linear algebra on sparse adjacency matrices to implement graph operations, which lets it achieve high performance. It understands OpenCypher queries.
CUBRID is a comprehensive GPL/BSD open source relational database management system highly optimized for Web Applications. CUBRID is being developed in C/C++. Includes native HA, online hot backup, and other features. JDBC, PHP, ODBC/.NET, Ruby & Python APIs.
UnQLite is a in-process software library which implements a self-contained, serverless, zero-configuration, transactional NoSQL database engine. UnQLite is a document store database similar to MongoDB, Redis, CouchDB etc.
The GridGain In-Memory Data Fabric is a proven software solution, which enables high-performance transactions, real-time streaming and fast analytics in a single, comprehensive data access and processing layer.