Just to throw a couple of examples out there. One is in the post below. It’s a little complicated, but basically I’m setting a unique ID in a row, then I assign that unique ID to rows in another table via a list whenever a row is clicked. I do this to indicate that the row is “selected”. Instead of clearing the unique id from multiple rows, I simply change the unique id in the parent table which essentially resets all other rows. Hopefully the post makes more sense when you read it.
Another real world example…at my day job I sometimes work with mapping software. Every single piece of farmable land in the United States has a shape that outlines it’s borders. There’s upwards of 100 million individual pieces of land (shapes). In the data that we receive from the government, each row is a shape and each shape has a unique ID. They call it a CLU, but it’s really a GUID (or a unique ID). It’s simply a unique value that can be assigned without having to compare to an existing database of ID’s to check if it’s a duplicate. It will always be unique. The odds of ever getting a duplicate ID are astronomically high and very very unlikely to happen.