[02/03] program practice

HI guys,

this is kind of a general question.
im just seeking some advice

I want to make a program that you install on a users pc.
The program requires alot of data to be stored, edited and updated.

What i want to know is the best way to store data in this case.

Am i wrong in thinking that if i want to use an sql database that the user shall have to have sql installed on thier machine.(with the database)

if i use xml files these xml files shall become very large. will this become a problem in the future?

any ideas on this would be great

thanks again