I never updated data this way before, and after having made some tests, it turns out that db.table.lft type is a Field that is converted into a string and then an integer later (I don't know how).
And I try the example from the book db(db.table.lft>0).update(lft=db.table.lft+1) appends the string '1' to the value (casted to string) of db.table.lft (this seems very weird to me because db.table.lft type is Field) For example if db.table.lft (Field, type int) row value is 12345, db.table.lft+1 after db update will give 123451 Or am I missing something ? On Wednesday, May 28, 2014 8:21:56 AM UTC, Marian wrote: > > I want to negate a value with this expression: > > db(db.table.lft > 0).update(lft = 0 - db.table.lft) > > but I get the following TypeError: > TypeError: unsupported operand type(s) for -: 'int' and 'Field' > > My workaround is: > db(db.table.lft > 0).update(lft = db.table.lft - db.table.lft - db.table.lft) > > > *It seems that update expression need to start with the field or do I miss > something?* > > -- Resources: - http://web2py.com - http://web2py.com/book (Documentation) - http://github.com/web2py/web2py (Source code) - https://code.google.com/p/web2py/issues/list (Report Issues) --- You received this message because you are subscribed to the Google Groups "web2py-users" group. To unsubscribe from this group and stop receiving emails from it, send an email to web2py+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
