QGIS plugin saving layerstyle

I try to use

Error = ""

vLayer.saveStyleToDatabase ("styleName", "description", True, "", Error)

in a python-plugin for QGIS 2.6

to save the data but have no success.

No error is written. First of all , where the table should be? I think, in the datasource-db (sqlite) But i can't find anything.

Any Help?