$($Ch $4)$ Which of the following statements about the requirements of table design is incorrect?

Each attribute in a table must have a unique name.

Values of a specific attribute must be of the same type.

Each attribute $($column$)$ of a record $($row$)$ must be single$-$valued.

All other non$-$key attributes in a table must describe a characteristic of the class $($table$)$ identified bv the fore