A tier in which the database resides along with the query processing language is called

In three-tier architecture, each tier has one clearly defined job. The data tier is the layer that stores the actual data and includes the database management system together with the query processing language (such as SQL) used to store, retrieve, and manipulate that data.

The application tier, by contrast, contains the business logic and processing rules, while the presentation tier only displays information to the user. Since the question specifically describes a tier that holds both the database and the query processing language, it is describing the tier responsible for data storage and retrieval, which is the data tier.

A common mix-up is treating the application tier as the place where data is stored, but the application tier only requests data from the data tier through the query language, it does not hold the data itself.

Exam tip: whenever a question mentions a database together with a query language in the same breath, it is pointing to the data tier.