If you specify a ``field.length`` ('string defaults to 512) you get a
default validator that will give errors if you try to insert more than
``length`` chars.By doing this you write code that is not portable. Why? How is this different in practice than doing ``default=request.now``? Massimo On Aug 29, 9:41 am, Kevin <[email protected]> wrote: > > To illustrate in Field() you > > have a length argument that puts a length constraint at the database level > > i.e > > the actual field definition (CHAR(10)). At the form level you also have > > IS_LENGTH which is used by SQLFORM to perform basically the same function. > > Ah, but just as you wanted to do something that nobody else in the > web2py community has needed yet (I'm sure more will over time), it may > be that someone else will need something you haven't thought of -- in > this particular case, the disparity between your idea of what field > length definitions should be used for vs the behavior of most (all?) > SQL RDBMS. In everything I've used, it is not an error (or even > necessarily a bad thing) to pass a 200 character string to a CHAR(50) > field, since the string will simply be truncated to the length of 50. > > So you could have a field defined as: > > CREATE TABLE message ( > id INT PRIMARY KEY, > short_description VARCHAR(50) UNIQUE NOT NULL, > content TEXT NOT NULL > ) > > This would allow you to do simple inserts like the following and have > them work as expected (optimize when optimization is needed): > > db.message.insert(short_description=text, content=text) > > > > > Traceback (most recent call last): > > File "/home/aklaver/software_projects/w2py/web2py/gluon/restricted.py", > > line > > 188, in restricted > > exec ccode in environment > > > File > > "/home/aklaver/software_projects/w2py/web2py/applications/hplc/controllers/appadmin.py", > > line 410, in <module> > > File "/home/aklaver/software_projects/w2py/web2py/gluon/globals.py", line > > 96, > > in <lambda> > > self._caller = lambda f: f() > > > File > > "/home/aklaver/software_projects/w2py/web2py/applications/hplc/controllers/appadmin.py", > > line 124, in insert > > form = SQLFORM(db[table], ignore_rw=ignore_rw) > > File "/home/aklaver/software_projects/w2py/web2py/gluon/sqlhtml.py", line > > 694, > > in __init__ > > default = field.formatter(default) > > File "/home/aklaver/software_projects/w2py/web2py/gluon/sql.py", line > > 2869, in > > formatter > > value = item.formatter(value) > > File "/home/aklaver/software_projects/w2py/web2py/gluon/validators.py", > > line > > 2023, in formatter > > year = value.year > > AttributeError: 'Expression' object has no attribute 'year' > > > > So perhaps this should go in the FAQ. > > > -- > > Adrian Klaver > > [email protected]
