What is the role of indexing in a database?

Indexing plays a critical role in enhancing query performance within a database. An index is a data structure that improves the speed of data retrieval operations on a database table at the cost of additional space and maintenance overhead. By creating an index on one or more columns of a table, the database can quickly locate and access the specific rows that meet search criteria without having to scan the entire table.

This is especially beneficial in large datasets where searching without an index could lead to sluggish performance due to the inefficiency of full table scans. When queries are executed, the database management system can utilize the index to retrieve results much faster, thus improving overall application performance and user experience.

In contrast, the incorrect options do not accurately represent the primary purpose of indexing in a database. Processing transactions more slowly contradicts the function of indexing, as the primary aim is to expedite operations. While user access control is important, it is not associated with indexing; rather, it revolves around user permissions and security protocols. Lastly, creating data backups pertains to data recovery and preservation, which is unrelated to the primary use of indexing in query speed optimization. Therefore, the correct answer highlights the essential advantage that indexing brings to database management.