Datomic is described as 'database of flexible, time-based facts, supporting queries and joins, with elastic scalability, and ACID transactions' and is an app in the Development category. There are more than 25 alternatives to Datomic for a variety of platforms, including Linux, Windows, Mac, Online / Web-based and BSD. The best alternative is MongoDB, which is free. Other great apps like Datomic are Microsoft SQL Server (Freemium), Apache Cassandra (Free, Open Source), RethinkDB (Free, Open Source) and CockroachDB (Free).
MarkLogic is the only Enterprise NoSQL database, bringing all the features you need into one unified system: a document-centric, schema-agnostic, structure-aware, clustered, transactional, secure, database server with built-in search and a full suite of application services.
The Starcounter database is built with the real-time systems of today in mind. Real-time systems supporting thousands or millions of simultaneous users. Systems like online stores, location-based services or banking applications.
Datahike is a durable Datalog database powered by an efficient Datalog query engine. This project started as a port of DataScript to the hitchhiker-tree. All DataScript tests are passing, but we are still working on the internals.
Amazon Redshift is a fast, fully managed, petabyte-scale data warehouse solution that makes it simple and cost-effective to efficiently analyze all your data using your existing business intelligence tools.
Postgres-XC is a write-scalable synchronous multi-master PostgreSQL cluster with the following features. 1) Both read and write scalability. 2) Configured with more than one server. 3) Complete global transaction and visibility management.