Looking for a word that describes a specific way to write code that does not have adverse effect if executed multiple times

I used to know of a word that is used to describe the impact (more lack of it) of running a programming script multiple times. To understand this better, let me try to give an example.

Let’s say I create a script to drop a table from a database. If the table already exists in the database and I run my script, it will work OK and will drop the table. If, however, I run my script second time, it will fail as the script will not find the table. This can be avoided if I modify my script to drop the table only if it exists. If write my script to do IF-EXISTS-THEN-DROP then I can run it any number of times without an issue. There is a single word that describes this type of script but I can’t remember it now. I would appreciate if any of you can help.