PHP is a widely-used scripting language that is especially suited for web development. It can be embedded within HTML and is commonly used to create dynamic web pages or web applications.

PHP can be used to interact with various database management systems (DBMS), allowing developers to store and retrieve data from a database. Some popular DBMS that can be used with PHP include:

1. MySQL: MySQL is a popular open-source relational database management system. It is often used with PHP due to its compatibility and ease of use. PHP provides built-in functions and extensions to connect to a MySQL database and perform various operations such as executing queries and retrieving results.

2. PostgreSQL: PostgreSQL is another popular open-source DBMS that is known for its robustness and support for advanced features such as JSON data type and full-text search. PHP provides extensions such as “pg” to connect to a PostgreSQL database and interact with it.

3. SQLite: SQLite is a self-contained, serverless DBMS that is embedded within the application itself. It is lightweight and requires minimal configuration. PHP provides a simple and easy-to-use SQLite extension for interacting with SQLite databases.

4. Oracle Database: Oracle Database is a relational DBMS that is widely used in enterprise applications. PHP provides an OCI8 extension that allows developers to connect to an Oracle database and perform various database operations.

5. Microsoft SQL Server: Microsoft SQL Server is a popular DBMS in Windows environments. PHP provides a PDO (PHP Data Objects) driver that allows developers to connect to a SQL Server database and interact with it.

In addition to these DBMS, PHP also supports other databases such as MongoDB (a NoSQL document database), Redis (a key-value store), etc. The choice of DBMS depends on the requirements of the project and the features provided by the DBMS. PHP provides a consistent API to interact with various DBMS, allowing developers to switch between different DBMS without changing much of their code.