Information security is becoming increasingly vital in a variety of applications. Database applications are no exception, and protecting information based on encryption plays a vital role in the protection of sensitive data. Securing data in several disciplines is a critical concern. Encryption was applied as a mechanism to secure data by database management systems and their applications. A promising approach has been seen in adopting multilevel security and encryption based on multilevel security. Recently, there has been an adaptation of the structure query language to be used in the encryption based on multilevel security; the used models are very time-consuming, especially for the large size of the database. In this paper, we proposed modifications of the models of select, update, and delete operations. The proposed modifications enhanced the performance of the models of select, update, and delete operations. The modification relies on the fact that we avoided repeating the decryption process and replaced it with a single encryption process. The obtained results show that the performances of the proposed modifications are better than the original model.