I am presently carrying out a program for any Notary for storing his clients informations, and here's my concern:

XML + Serialisation usage versus Vector (of Objects) + Serialisation usage versus SQL Databases.

Using Qt, I must know which will be the perfect for storing clients, searching and modifying the clients?

I've got a plenty of textboxes and checkmarks (Names, adresses, Retailers informations, Purchasers informations, etc).

Interesting ideas!

Personally, I'd opt for an SQLite database. XML is ideal for interchange between programs or storage, although not the best for searching. Vector serialization isn't so easily recorded. SQLite is well-known, embedded (no separate process needed), simple to search, and efficient for speed. I'd take into account that the very best compromise for speed and self-documentation.

I am presuming it is really an application for just one person's keeping of legally significant records.