qt - How to store a QRect in Sqlite? -

i need store qrect in sqlite database. (i've searched around did not see on this)

does qt/qsqlite automatically convert qrect qvariant , handle whatever decomposition needed or have myself , store origin , size values in 4 separate fields?

if so, , generalize other qt data types, possible store qvector, qlist? define these (and qrect, etc.) blob types in table definitions?

sqlite relational database , things cannot store c++ objects directly.

actually c++ object model doesn't allow transparent persistence can try close using specialized tools or libraries. important point objects must designed support persistence.

if don't need transparent persistence explicit store/retrieval of objects can pick serialization method (e.g. using single string, or using separate fields attributes). each method has pros , cons depending on want database (e.g. kind of searches or updates want do).

something unfortunate c++ metaprogramming abilities poor (just little better c) , example introspection impossible.

this means need write serialization code each class need support or need find/buy external tool looking @ class definition .h generate needed code you. must external tool because serialization outside limited reach of template metaprogramming.

qt has specialized serialization machinery qdatastream may can use looking for: example qrect serializable , qlist<t> serializable if t is.

using require serialize qbytearray first , store blob inside sqlite. example after writing

template<typename t> qbytearray serialize(const t& x) {     qbytearray ba;     qdatastream s(&ba, qiodevice::writeonly);     s << x;     return ba; }  template<typename t> t deserialize(qbytearray& ba) {     qdatastream s(&ba, qiodevice::readonly);     t res; s >> res;     return res; } 

you can serialize object directly qbytearray with

qbytearray ba = serialize(x); 

and can deserialize with

x x = deserialize<x>(ba);