IBM on Positional Parameters
Friday, May 7, 2004
While I'm sure there are plenty of good ways to explain positional method parameters so that even a dullard like me would understand them, nobody can quite teach it the way IBM does (excerpted from DB2 documentation):
An argument is a value passed to a method upon invocation. When a method is invoked in SQL, it is passed the subject argument (of some structured type) and a list of zero or more arguments. They are positional in that the semantics of an argument are determined by its position in the argument list. The subject argument is considered as the first argument. A parameter is a formal definition of an input to a method. When a method is defined to the database, [...], its parameters are specified (with the subject parameter as the first parameter), and the order of their definitions defines their positions and their semantics. Therefore, every parameter is a particular positional input of a method. On invocation, an argument corresponds to a particular parameter by virtue of its position in the list of arguments.