DROP TABLE crop;

DROP TABLE animal;

CREATE TABLE crop

$($crop$\_$id NUMBER $(6)$ PRIMARY KEY,

crop$\_$name VARCHAR$2(20)$ UNIQUE,

seed$\_$cost NUMBER $(4,2),$

yield$\_$per$\_$acre NUMBER $(5,2),$

num$\_$acres NUMBER $(4),$

avg$\_$cost NUMBER $(5),$

date$\_$ideally$\_$plnt DATE,

harvest$\_$time INTERVAL DAY $(2)$ TO SECOND $(3),$

yield$\_$cost calculated$\_$field NUMBER$(10,2)$ GENERATED ALWAYS AS $($yield$\_$per$\_$acre $*$ avg$\_$cost$)$ STORED$)$;

CREATE TABLE animal

$($animal$\_$id NUMBER $(6)$ PRIMARY KEY,

animal$\_$name VARCHAR$2(20)$ NOT NULL,

type CHAR $(2),$

num$\_$head NUMBER $(5),$

maturity$\_$time INTERVAL YEAR $(2)$ TO MONTH,

offspring VARCHAR$2(3),$

crop NUMBER $(6)$ NOT NULL REFERENCES crop $($crop$\_$id$))$;