CREATE TABLE Product (
"Product_id" int,
"Stock_quantity" int,
"Product_name" varchar(50),
"Model" varchar(50),
"Average_rating" float(3),
"RAM" int,
"Color" varchar(20),
"Price" float(10),
PRIMARY KEY ("Product_id")
);

CREATE TABLE Sale (
"Sale_id" int,
"Sale_date" date,
"Employee_id" int,
"Customer_id" int,
"Product_id" int,
"Product_quantity" int,
"Rating" int,
PRIMARY KEY ("Sale_id"),
FOREIGN KEY("Employee_id") REFERENCES Employee("Employee_id") ,
FOREIGN KEY("Customer_id") REFERENCES Customer("Customer_id") ,
FOREIGN KEY("Product_id") REFERENCES Product("Product_id")
);


CREATE TABLE Computer (
"Type" varchar(10),
"Processor" varchar(20),
"Monitor_size" int
)  inherits(Product);

CREATE TABLE Mobile (
"Os" varchar(30),
"Screen_size" int
 ) inherits(Product);

ERROR: insert or update on table "sale" violates foreign key constraint "PK_Product_id"
SQL state: 23503
Detail: Key (Product_id)=(12) is not present in table "product".