Which of the following databases are commonly used with Liferay?

The choice of MySQL, PostgreSQL, Oracle, and Microsoft SQL Server as commonly used databases with Liferay is well-founded. Liferay is designed to work efficiently with relational databases, and all these options represent robust, enterprise-grade databases widely used in production environments.

MySQL is particularly popular due to its open-source nature, ease of use, and strong community support. PostgreSQL is favored for its advanced features, including support for various data types and a powerful query language, making it highly adaptable to complex applications. Oracle is a long-standing player in the database market, known for its high performance and extensive features that cater to large enterprises. Microsoft SQL Server is also a strong contender, especially in environments that heavily utilize Microsoft technologies, providing seamless integration and enterprise-level capabilities.

These databases provide the necessary transaction support, performance, and scalability that Liferay requires, especially for applications with significant data and user traffic. In contrast, the other options listed consist of databases that do not align as closely with Liferay's typical use cases or have different architectures that are generally not a primary choice for this specific platform.