In any kind of programming, variables are simply placeholders for values that are used in the execution of a program. The values in the variables might change on different executions. For example, the
day_of_week variable might hold the value of
Tuesday today, but
Wednesday tomorrow. Variable values might also change within a single execution. For example, we might use a variable to hold the running total of invoices processed. As each invoice is processed, the value held in the variable will change.
The use of variables allows our jobs to be dynamic and not have hardcoded values in them.
In this chapter, we will learn about: