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Relational Databases (SQL)

Relational (SQL) databases: open-source and commercial engines, distributed SQL, managed Postgres and learning resources.

44 topics•6 categories•Updated October 2026

What Is a Relational Database?

7 entries

A relational database stores data in tables of rows and columns, relates tables through keys and queries them with SQL, with transactional (ACID) guarantees. Relational systems range from embedded engines such as SQLite to enterprise servers and distributed SQL systems that scale across nodes. Descriptions below follow each vendor's or project's own pages and are not rankings; release facts come from project sites and GitHub.

01Database SystemsDatabase systems hub, on this site. 02Distributed SQL DatabasesNewSQL systems at multi-node scale, on this site. 03SQL Databases on CloudsManaged relational services from the major clouds, on this site. 04Cloud Database Management SystemsCloud DBMS offerings, on this site. 05Translytical Data PlatformsUnified transactional and analytical platforms, on this site. 06NoSQL DatabasesNoSQL hub, on this site. 07Cloud Data WarehousesWarehouses for analytics, on this site.

Open-Source Relational Databases

6 entries

Widely used open-source engines.

08PostgreSQLOpen source object-relational database system with over 35 years of development. PostgreSQL 19 release candidate 1 was announced on 15 October 2026, and the current documentation covers PostgreSQL 18.6; each major version is supported for five years. 09MySQLOracle-owned open-source relational database; the mysql.com site and documentation returned 403 to automated checks and may need a manual click. 10MariaDBCommunity-developed MySQL-compatible database; GitHub lists mariadb-13.0.2 (15 September 2026) as the latest release. 11SQLiteEmbedded, serverless SQL database engine; the SQLite site lists version 3.54.1 (16 October 2026) as the latest release. 12FirebirdOpen-source relational database that describes itself as a true open-source relational database. 13DuckDBIn-process SQL OLAP database; PyPI and GitHub list 2.0.0 (21 October 2026) as the latest release.

Commercial Relational Databases

5 entries

Enterprise databases from the large vendors.

14Oracle DatabaseOracle describes Oracle Database 26ai for AI-enabled application development and critical workloads. 15Microsoft SQL ServerMicrosoft describes SQL Server 2025 as an enterprise data platform with developer-first features and AI model integration. 16IBM Db2IBM describes a database for mission-critical workloads with low-latency transactions and real-time analytics across cloud, hybrid and on-premises. 17EDB Postgres AIEDB describes an enterprise Postgres platform; its throughput and scale claims are the vendor's own. 18PerconaPercona describes enterprise-class open-source database software, support and services for MySQL, PostgreSQL, MongoDB, Redis and MariaDB.

Distributed and Scale-Out SQL

6 entries

Relational systems that scale across nodes.

19CockroachDBCockroach Labs describes a cloud-native, distributed SQL database for resilience and horizontal scale; GitHub tags include v26.2.10. 20YugabyteDBDistributed SQL database with PostgreSQL compatibility; GitHub lists v2026.1.2.0 (22 September 2026) as the latest release, and the yugabyte.com site returned 403 to automated checks. 21TiDBPingCAP describes a distributed SQL database for AI agents, with vectors, transactions and analytics in one engine. 22VitessDatabase clustering system for horizontal scaling of MySQL; GitHub lists v24.0.5 (13 October 2026) as the latest release. 23CitusCitus describes distributed tables for Postgres; GitHub lists v14.3.0 (23 October 2026) as the latest release. 24Google Cloud SpannerGoogle describes a single database that combines relational, graph, key-value and search.

Managed Postgres and Postgres Extensions

6 entries

Services and extensions built on PostgreSQL.

25Amazon AuroraAWS describes a global-scale relational database service with full MySQL and PostgreSQL compatibility. 26Google AlloyDBGoogle describes a fully managed PostgreSQL-compatible database service for demanding enterprise workloads. 27SupabaseSupabase describes a Postgres database with authentication, instant APIs, realtime, functions, storage and vector embeddings. 28NeonThe neon.com site now describes a backend built on Lakebase Postgres with branching and serverless operation. 29TimescaleDBTimescale describes a PostgreSQL platform for time series; GitHub lists 2.31.0 (20 October 2026) as the latest release. 30pgvectorOpen-source vector similarity search for Postgres.

Learning and Reference

14 entries

SQL tutorials, documentation and rankings.

31PostgreSQL documentationOfficial documentation for the current PostgreSQL release (18.6). 32MariaDB documentationMariaDB documentation, release notes and learning resources. 33SQLite documentationOfficial SQLite documentation. 34Modern SQLReference on SQL features beyond the basic relational model. 35Use The Index, LukeSQL indexing and tuning tutorial for developers covering all major SQL databases. 36SQL Style GuideGuide to formatting and naming SQL. 37DB-Engines RankingPopularity ranking of 440 database management systems; the ranking is based on the site's own popularity metrics. 38Database Performance TuningEXPLAIN, Query Store, monitoring, pooling and benchmarking tools. 39Database IndexingB-tree, GIN, BRIN, LSM and vector indexes with docs and tools. 40Database ReplicationNative replication, failover tools, multi-primary and cloud replication. 41Database ShardingVitess, Citus, MongoDB, Spanner and shard key design. 42Database TransactionsACID, isolation levels, MVCC, distributed transactions and sagas. 43Database Backup and RecoveryPITR, native backup tools, cloud backup, Kubernetes and DR planning. 44Database SecurityAccess control, encryption, auditing, masking and hardening for databases.

Frequently Asked Questions

What is a relational database?

A database that stores data in tables of rows and columns, links tables through keys and queries them with SQL. Relational databases provide ACID transactions and enforce schemas and constraints.

Which relational database should I choose?

PostgreSQL is a common default for new applications because of its features and extensions. MySQL and MariaDB are widely used for web workloads, SQLite suits embedded and local storage, and Oracle Database, SQL Server and Db2 serve enterprise estates. For horizontal scale, consider distributed SQL systems.

What is distributed SQL?

Databases such as CockroachDB, YugabyteDB, TiDB and Spanner that keep SQL and ACID semantics while spreading data across many nodes for scale and resilience. See the Distributed SQL Databases page.

What is the difference between OLTP and OLAP databases?

OLTP databases handle many small transactions, such as orders, while OLAP databases scan large datasets for analytics. PostgreSQL and MySQL are mainly OLTP, while DuckDB and cloud warehouses are built for OLAP. HTAP or translytical platforms try to serve both.

Can relational databases store vectors and JSON?

Yes. PostgreSQL supports JSON and, with the pgvector extension, vector similarity search, and many other relational databases have added JSON and vector types. See the Vector Databases page for dedicated alternatives.

How current is this page?

Links and release facts were checked on 31 October 2026. MySQL and its documentation and the yugabyte.com site returned 403 to automated checks. Vendor descriptions follow their own pages and are not rankings.