As a database administrator, you will often need to apply multiple commands as part of the same overall task. That task could be one of the following:
Many different actions on multiple tables
The same action on multiple tables
The same action on multiple tables in parallel
Different actions—one on each table—in parallel
The first is a general case where you need to make a set of coordinated changes. The solution is "write a script", as we've already discussed. We can also call this static scripting because you write the script manually and then execute it.
The second type of task can be achieved very simply with dynamic scripts, where we write a script that writes another script. This technique is the main topic of this recipe.
Performing actions in parallel sounds really cool, and it would be useful if it was easy. In some ways it is, but trying to run multiple tasks concurrently and trap and understand all the errors is much harder. And if you're thinking it...