Dangling Predicates and Function Call Optimization in the Oracle Database

Oracle Databases have always been considered the driving engine of information systems performance. Currently, it is not enough to keep only current valid records but also historical, as well as future plans need to be treated, forming a temporal database layer. The input data themselves are treated in various manner, processed, and stored. To ensure performance, database indexes are created to locate the row in the physical storage efficiently by focusing not only on the attribute values but also function results defined in PL/SQL. This paper emphasizes function development in PL/SQL by pointing to the function-based indexing and optimization for the SQL usage reducing content switch. Besides, it deals with the dangling predicates for the CASE command to ensure proper definition and usage methodology.