With regular registration numbers, you start counting at 1 and numbers can overlap. A GUID can be used for people, cars, files, webpages, colors, anything. If you pick a huge random number (39 digits long), it’s really unlikely that someone will pick the same one. This gives us 2^128 or about 10^38 numbers. The format is a well-defined sequence of 32 hex digits grouped into chunks of 8-4-4-4-12. They are usually 128 bits long and look like this in hexadecimal: GUIDs are large, enormous numbers that are nearly guaranteed to be unique. The problem with counting is that we want to create ID numbers without the management headache. Can people guess what the next ID will be? How many IDs have been issued?.Can IDs be shared between products? Is Social Security Number 1 different from ISBN 1?.Who handles simultaneous requests and eliminates duplicates?.
Who does the counting? A central authority?.Just start with ISBN #1 and add one for each new book. “We don’t need no stinkin’ GUIDs,” you may be thinking between gulps of Top Ramen, “I’ll just use regular numbers and start counting up from 1.” You may see the term UUID tossed about (universally unique identifier), a nitpicky word for those whose numbers are unique not only within the globe, but throughout the entire universe.Īny way you title it, GUIDs or UUIDs are just big, gigantic ID numbers. “John Smith” may be many people, but Social Security Number 123-45-6789 refers to one person exactly.Ī GUID (globally unique identifier) is a bigger, badder version of this type of ID number. Numbers help us reference items unambiguously.
Cars have VINs, even people have social security numbers. Books have ISBNs and products have barcodes.
0 kommentar(er)
