What is the primary function of a query in a database system?

The primary function of a query in a database system is to extract data based on specified criteria. Queries allow users to retrieve specific information from a database by using conditions that define what data is of interest. This enables users to filter, sort, and analyze data effectively, making it possible to obtain insights and answers to particular questions without needing to view the entire dataset.

Queries can be written in various database query languages, with SQL (Structured Query Language) being the most commonly used. By specifying criteria such as filters, joins, or sorting, users can request exactly what they need from the database, which enhances efficiency and data management capabilities.

The other choices refer to different functions within a database. For instance, permanently deleting data, structuring database design, and creating tables and relationships are tasks more associated with data management and administrative functions rather than the specific role of querying data.