Hmmm. Experian in the UK
I know Experian is a multi-national so I can't comment on countries than the UK and my info is a few years out of date, but I used to work with the Experian computer/databases and the following is a very high level view of what is stored.
If you have anything owning to a credit-provider then they register the fact that a payment is required at a certain point. If a payment is received successfully then they record that. If it isn't then they record that also and they record if, for some reason thay payment was subsequently not required after all. So a three state flag. (actually is also sorted how late a payment was also)
"CompanyX 1 1 1 1 2 1 2 3 1 1 1 0 0 0 "
Companies purchasing services from Experian would typically simply take Experian's "summary" information on how good a credit risk you are - the number of payments wanted on time compared to how many were received. Offset by the severity of late payments. Basically that's the "credit rating". What they do with that information is up to them. Many credit providers like payers who are often slightly late, but not too much, as they incure charges and provide income for the companies. The information held is supposed to cycle out over seven years.
If you have never taken anything on credit, no loans, mortgages, catalogue purchases (student loans don't count I'm told) then you will not have a credit history/ record AT ALL. This is *not* the same as a good credit history and in fact if you are 28(ish)+ and have never had credit you may find it hard to do so. The tip we used to give such people was to take out a catalogue account, make a small purchase and make all the payments, regularly and on time.
Banks typically hold their own information and take more information from Experian than just the basic "credit-rating". They use this to generate a Delphi score which is different for each bank and involves lots of high voodoo. You have access to your credit history and can request corrections if you can prove they are wrong but good luck finding out about the Delphi score(s).
I don't know if this has changed much but Equifax used to mirror the Experian data (though not all of it) over night and so typically lagged by 24 hours or so, but had the same info - a reason they were always a bit cheaper - they were a reseller basically.