Do universities know I you resat any of your gcse?

It's almost as if there's a national database of all students exam results and entries.....

Like this one https://www.gov.uk/government/collections/national-pupil-database

I don't quite understand so student are require to enter all the resits from gcse?

For example let say if you fail to get a C on Math(compulsory) but you have gotten a D instead.. On ucas application it will say you got a D on Math and a "blank space " on Math as this prove you are resitting it again. So again let's say if i were to resit the math three times and out of the first two i have gotten E and D . <- would you still add this toward the pending grade for math resit ? the E and D? since you already gotten a D at first try? But at the 3rd try (last resit) you got a C so you can just fill the blank pending with a grade C and ignore the previous two attemps ( D and E ) since they were not needed as it make no difference.

This is what i did for the resits that i have done in the past as it's pretty much
self explanatory - once you know it make no difference because you resit grade were lower than the first attemp and until you get the requrie gade from the resits or many resit attemps you just need to input that " require" grade , not fail grades.

Was that U in your 3 main A-level course? then i guess it would have appear. I have gotten a U on my 4th A-level so i dropped it at the end and kept my other 3 A-level course . So the U existence was never on my ucas as i will be just using 3 A-level to enter a unvieristy course.

Say if I do worse on my retake do I enter the worst one? Or do I declare my best one (math GCSE)