How is patient record been use in pharmacy area, what is the data used or and
what functions (activities, processes, etc) the data contribute to.

I can answer this question in part, and hopefully other people will
chip-in so you get a more full-rounded answer.

I'm not a pharmacist myself, I'm a drug safety scientist, but I can
tell you that patient data is used (data sources: doctors,
pharmacists, nurses and the patient themselves), in the collection of
information regarding adverse drug effects, that is to say, if you
inform your health care provider of any side effect whilst on a drug;
trivial or otherwise, or seemingly completely unrelated (like you were
involved in an accident), you were taken seriously ill or if you just
experienced minor afflictions, they are obliged to inform the
regulatory authorities (information is passed on to pharma company) or
direct to pharma company (information then passed to reg
authority)(information is shared) regarding the event, some patient
data required, such as age, gender, race, weight, date of birth,
initials (usually one of the above required) in order to compile a
list of known (or expected) side efects for the drug, drug-drug
interactions, to track emerging side effects that may of concern,
(implications are that drug could be pulled from the market- like
viox), and to track the side effects in new populations (such as
pregnany women who got pregnant despite being warned not to, to see
possible fetus implications) (think thalidomide)).

ditto above from one side of the story.

From the patient's perspective:

If your cardiologist prescribed a certin blood pressure drug, and your
opothomologist prescribed a kind of eye drops, you could have a
violent reaction if they were used together.

If you take birth control pills, your dentist could prescribe an
antibiotic for your root canal that would render your birth control
ineffective.  The pharmacist could alert you to this.

If you eat grapefruit, and your doctor prescribes a cholesterol
lowering drug, it could damage your liver.

A regular pharmacist with a good consultative medical history is your friend.