Description: Query efficiency in database systems refers to the effectiveness of query execution in terms of speed and resource usage. This concept is fundamental in the database realm, as an efficient query can significantly reduce response time and memory consumption, resulting in optimal system performance. Query efficiency is influenced by various factors, such as database structure, table design, indexing, and the complexity of the queries themselves. In SQLite, which is a software library that implements a lightweight and self-contained SQL database engine, query efficiency is crucial, especially in mobile and embedded applications where resources are limited. To achieve high efficiency, it is advisable to use appropriate indexes, avoid unnecessarily complex queries, and optimize read and write operations. The ability to handle queries efficiently allows developers to create fast and responsive applications, enhancing the end-user experience. In summary, query efficiency in database systems is a key aspect that directly impacts the performance and usability of applications relying on this technology.