IIRC, 'n' cannot change once the array is declared. Thus, this isn't really a dynamic array, just allowing you to choose the size of the fixed array at runtime. For databases, what you should be looking at are implementing link lists, stacks and queues. Also, if this database is going to be designed to hold more than a few hundred records, you should read up on hash tables as well.
Also, remember that linked lists are quite an inefficient way of storing large numbers of record. A vector coupled with a hash table would be much much better.
An excellent (if technical) book to read to learn data structures is "Data Structures Using C and C++" by Yedidyah Langsam, Moshe J. Augenstein and Aaron M. Tenenbaum. The book makes an excellent guide to the world of data structures.

Cheers,
cgkanchi