[C++] Loading a structure from a configuration file

[KJG]

Hello :)
I am doing a project in C++ - a simple data base (with "one table").

I want to build that data base using a LIFO or FIFO list, but this doesn't matter here ;)
The only problem I have is that the structure of the data base is not "locked" in the code of the program, but when the program starts, it is "loaded / implemented" from a "configuration file" called "data.txt".
So the user, before she or he runs my program opens the file "data.txt" and writes the structure of the data base that se/he wants to create. This means that one time my program can be used to create a data base of students with fields such as "name / surname / gender / age / idnumber / university" but the next time it can be used for a data base of CD's with fields like - "author / release date / no. of tracks / etc.".
How to do that "loading" of a structure of a data base from a file, when the user runs my data-base creator (my C++ program).
I am sorry for this weird and "repetitive" thoughts. I don't reallly know how to explain it in a good way, so that everyone knows what I ment.
I would very much appreciate even the smallest advie.
Thanks in advance and have a nice day :)
Chris