read only

I have an object which mimics a table structure in sql. Lets call this object validation. Validation has a property isrequired with a get and set. when i use this property in code i.e. validation val = new validation and then try to change the value of isrequired intellisense says i can not assign to this isrequired because it is read only. I have a user that wants some items for some objects to be required where as other objects isrequired is false. The table that this object mimics has fieldname and isrequired either true or false. in this case the database has isrequired as true. I just want to change the isrequired in the object and not affect change in the database table. when i use form.fieldname.isrequiered = false it tells me I can not assign because it is read only. Thanks.