Need a bit of SQL help

Miscellaneous Forums/General Discussion/Need a bit of SQL help

Anybody here clued up on SQL? I'm totally new to it all so I apologise if this is a stupid question.

Suppose I have a field called 'Fullname' defined as Varchar(20)... but some names might be longer than that occasionally.

Is there a way to define a text field without it having a pre-defined maximum length?