Check all the objects variables to see if they are valid, by default this
means is a column an integer or string, if you define methods like
validateEmail(), in your extended class then it
will be called to validate the row called 'email'. This may be useful if
called prior to an update or insert.., to generate error messages.
override this to set up your validation rules.
Return value
array - of validation results or TRUE
Note
This function can not be called
statically.
the examples below utilize the PEAR validation package