Database testing is checking the schema, tables, triggers, etc. of the database under test. This may involve creating complex queries to test the database and check it’s responsiveness. It’s checks data integrity and consistency.
DevOps, a compound of dev(development) and ops(operations), is a software development and IT operations. DevOps includes core practices such as planning and tracking, development, built and test, delivery and test, delivery and monitoring and operations.
Selenium is a portable framework for testing web applications. Selenium provides a playback tool for authoring functional tests without the need to learn a test scripting language. It also provides a test domain-specific language to write tests in a number of languages.