Hi,
Be careful with relation one-to-one : usually, it is not very used in a program.
And it is why there is not many informations about this relation in the tutorial of QxOrm.
The relation one-to-one can be used when 2 tables share the same id in the database (for example, 1 person can share the same id with a user, or a person can share the same id with a patient in a hospital, etc...).
In most case, you have to use the relation many-to-one.
For more informations about relationships, you can visit this web site :
http://www.xylax.net/hibernate/index.html