Updating client fields and SQL warn [VM4.0.7]

[hazael]

At the address:
administrator/index.php?option=com_virtuemart&view=userfields

When updating client fields, I get a warning from the database

vmError: vmTable store updateObject Incorrect integer value: '' for column 'cols' at row 1 UPDATE `satan_virtuemart_userfields` SET  [...]

Trying to save the string/varchar value '' (an empty string) to the column 'cols' and 'rows' which is an integer type.