[SOLVED] Problems in clearing a field from backend

I have a field holding an integer number.
Before entering a value in the field, it's empty as it should be.
Then I enter a number.
At some point I may like to remove the number, but I'm not allowed to do that.
I can enter a 0, but that's not empty of course.
But entering a blank field is not allowed.

Second thing, during testing I removed constraints from the field, so there were no minimum and no maximum, and then when entering a number I got this message:
DSF nummer : Year 9018534 is not between 0 and 0

I have no idea where 'Year' comes from, and yes, the number is not between 0 and 0, but there were no constraints set.

It does seem that the logic in auto-actions treats 0 as empty though, as the action email I've defined when entering a number in the field, was sent, and the action asks if '[var3_cb_dsf] is empty'.

An integer field is only initially null as no value exists. Once a save action occurs its typecasted to sanitize it and turns empty values into 0. There is no setting it to null. There is no unlimited maximum, if you specify 0 you're saying the maximum is 0. I've no idea where the "Year" is coming from either, but seams like a language string issue.

It does seem that the logic in auto-actions treats 0 as empty though, as the action email I've defined when entering a number in the field, was sent, and the action asks if '[var3_cb_dsf] is empty'.

NULL, empty, and 0 are all considered empty for CB Auto Actions conditional.