i want to create application in windows. i need to use databases which would be preferable best for pyqt application
like
sqlalchemy
mysql
etc.
SQlite is fine for a single user. 
If you are going over a network to talk to a central database, then you need a database woith a decent Python lirary. 
Take a serious look at MySQL if you need/want SQL. 
Otherwise, there is CouchDB in the Not SQL camp, which is great if you are storing documents, and can express searches as Map/reduce functions. Poor for adhoc queries.
which databases can be used better for pyqt application