Free database management systems

MySQL () is an open-source relational database management system (RDBMS). Its name is a combination of "My", the name of co-founder Michael Widenius' daughter My, and "SQL", the acronym for Structured Query Language. A relational database organizes data into one or more data tables in which data may be related to each other; these relations help structure the data. SQL is a language that programmers use to create, modify and extract data from the relational database, as well as control user access to the database. In addition to relational databases and SQL, an RDBMS like MySQL works with an o

PostgreSQL ( ), also known as Postgres, is a free and open-source relational database management system (RDBMS) emphasizing extensibility and SQL compliance. PostgreSQL features transactions with atomicity, consistency, isolation, durability (ACID) properties, automatically updatable views, materialized views, triggers, foreign keys, and stored procedures. It is supported on all major operating systems, including Windows, Linux, macOS, FreeBSD, and OpenBSD, and handles a range of workloads from single machines to data warehouses, data lakes, or web services with many concurrent users.

SQLite ( "S-Q-L-ite", "sequel-ite") is a free and open-source relational database engine written in the C programming language. It is not a standalone application; rather, it is a library that software developers embed in their applications. As such, it belongs to the family of embedded databases. According to its developers, SQLite is the most widely deployed database engine, as it is used by several of the top web browsers, operating systems, mobile phones, and other embedded systems.

MariaDB is a community-developed, commercially supported fork of the MySQL relational database management system (RDBMS), intended to remain free and open-source software under the GNU General Public License. Development is led by some of the original developers of MySQL, who forked it due to concerns over its acquisition by Oracle Corporation in 2009.

relational database management system

Free and open-source, distributed, wide column store, NoSQL database management system.

database software

software library providing embedded database for key/value data

HSQLDB (Hyper SQL Database) is a relational database management system written in Java. It has a JDBC driver and supports a large subset of SQL-92, SQL:2008, SQL:2011, and SQL:2016 standards. It offers a fast, small (around 1300 kilobytes in version 2.2) database engine which offers both in-memory and disk-based tables. Both embedded and server modes are available.

document-oriented database

thumb|RRDtool has a graph function, which presents data from an RRD in a customizable graphical format.

Neo4j is a graph database management system (GDBMS) developed by Neo4j Inc.

Kexi is a visual database applications creator tool by KDE, designed to fill the gap between spreadsheets and database services requiring more sophisticated development. Kexi can be used for designing and implementing databases, data inserting and processing, and performing queries. It is developed within the Calligra project but is released separately.

relational database management system

open source, non-relational, distributed database system

relational database management system

key-value database

CiviCRM ( C-R-M) is a web-based suite of internationalized open-source software for constituency relationship management that falls under the broad rubric of customer relationship management. It is specifically designed for the needs of non-profit, non-governmental, and advocacy groups, and serves as an association-management system.

Python object database management system

db4o (database for objects) was an embeddable open-source object database for Java and .NET developers. It was developed, commercially licensed and supported by Actian. In October 2014, Actian declined to continue to actively pursue and promote the commercial db4o product offering for new customers.

CUBRID ( "cube-rid") is an open-source SQL-based relational database management system (RDBMS) with object extensions developed by CUBRID Corp. for OLTP. The name CUBRID is a combination of the two words cube and bridge, cube standing for a space for data and bridge standing for data bridge.

ScyllaDB is a source-available distributed NoSQL wide-column data store. It was designed to be compatible with Apache Cassandra while achieving significantly higher throughputs and lower latencies. It supports the same protocols as Cassandra (CQL) and the same file formats (SSTable), but is a completely rewritten implementation, using the C++20 language replacing Cassandra's Java, and the Seastar asynchronous programming library replacing classic Linux programming techniques such as threads, shared memory and mapped files. In addition to implementing Cassandra's protocols, ScyllaDB also implem

Riak (pronounced "ree-ack" ) is a distributed NoSQL key-value data store that offers high availability, fault tolerance, operational simplicity, and scalability. Riak moved to an entirely open-source project in August 2017, with many of the licensed Enterprise Edition features being incorporated. Riak implements the principles from Amazon's Dynamo paper with heavy influence from the CAP theorem. Written in Erlang, Riak has fault-tolerant data replication and automatic data distribution across the cluster for performance and resilience.

DuckDB is an open-source column-oriented Relational Database Management System (RDBMS). It is designed to provide high performance on complex queries against large databases in embedded configuration, such as combining tables with hundreds of columns and billions of rows. Unlike other embedded databases (for example, SQLite) DuckDB is not focusing on transactional (OLTP) applications and instead is specialized for online analytical processing (OLAP) workloads. The project has over 6 million downloads per month.

EnterpriseDB (EDB) is an American company that provides software and services based on the open-source database PostgreSQL (also known as Postgres), and is one of the largest contributors to Postgres. EDB develops and integrates performance, security, and manageability enhancements into Postgres to support enterprise-class workloads. EDB has also developed database compatibility for Oracle to facilitate the migration of workloads from Oracle to EDB Postgres and to support the operation of many Oracle workloads on EDB Postgres.

Open source Bigtable implementation

free software/open source relational database management system (DBMS) that was forked from version 6.0 of the MySQL DBMS

eXist-db (or eXist for short) is an open source software project for NoSQL databases built on XML technology. It is classified as both a NoSQL document-oriented database system and a native XML database (and it provides support for XML, JSON, HTML and Binary documents). Unlike most relational database management systems (RDBMS) and NoSQL databases, eXist-db provides XQuery and XSLT as its query and application programming languages.

OrientDB is an open source NoSQL database management system written in Java. It is a Multi-model database, supporting graph, document and object models, the relationships are managed as in graph databases with direct connections between records. It supports schema-less, schema-full and schema-mixed modes. It has a strong security profiling system based on users and roles and supports querying with Gremlin along with SQL extended for graph traversal. OrientDB uses several indexing mechanisms based on B-tree and Extendible hashing, the last one is known as "hash index". Each record has Surrogate

analytical database software

BaseX is a native and light-weight XML database management system and XQuery processor, developed as a community project on GitHub. It is specialized in storing, querying, and visualizing large XML documents and collections. BaseX is platform-independent and distributed under the BSD-3-Clause license.

ArangoDB is a graph database system developed by ArangoDB Inc. ArangoDB is a multi-model database system since it supports three data models (graphs, JSON documents, key/value) with one database core and a unified query language AQL (ArangoDB Query Language). AQL is mainly a declarative language and allows the combination of different data access patterns in a single query.

ClickHouse is an open-source column-oriented DBMS (columnar database management system) for online analytical processing (OLAP) that allows users to generate analytical reports using SQL queries in real-time. ClickHouse Inc. is headquartered in the San Francisco Bay Area with the subsidiary, ClickHouse B.V., based in Amsterdam, Netherlands.

RethinkDB is a free and open-source, distributed document-oriented database originally created by the company of the same name. The database stores JSON documents with dynamic schemas, and is designed to facilitate pushing real-time updates for query results to applications. Initially seed funded by Y Combinator in June 2009, the company announced in October 2016 that it had been unable to build a sustainable business and its products would be entirely open-sourced without commercial support.

thumb|300px|LYME (software bundle) is based on Erlang and comprises Mnesia. It is entirely composed of [[free and open-source software]] Mnesia is a distributed, soft real-time database management system written in the Erlang programming language. It is distributed as part of the Open Telecom Platform.

Hypertable was an open-source software project to implement a database management system inspired by publications on the design of Google's Bigtable.

GT.M is a high-throughput key–value database engine optimized for transaction processing. (It is a type also referred to as "schema-less", "schema-free", or "NoSQL".) GT.M is also an application development platform and a compiler for the ISO standard M language, also known as MUMPS.

open source software

Infobright was founded as a commercial developer of column-oriented relational database software with a focus in machine-generated data. The company was later acquired in 2017 and then spun out in 2018 as an independent research and development organization today known as AQ Technologies based in Warsaw, Poland.