Comparative Study of Various Function Definitions Used in Oracle SQL Dialect

SQL language is a non-procedural language with the defined statements and available clauses. Many times, conditions and format of the output depend on the functions. In this paper, Oracle relational database system (RDBMS) is used. Functions to be called are commonly defined in the PL/SQL, consequencing in context switches necessity between the SQL and PL/SQL environments. This paper deals with the various techniques for defining functions to be used in SQL statements. It provides an methodology for defining functions. For the performance evaluation study, temporal conversion functions are covered, focusing on the introduced SQL macro.