The syntax for declaring PRIMARY KEY and FOREIGN KEY is designed to cope with composite keys, e.g. PRIMARY KEY (A, B, C). Suggest a simpler syntax for a CREATE TABLE declaration where the primary key...

The syntax for declaring PRIMARY KEY and FOREIGN KEY is designed to cope with composite keys, e.g. PRIMARY KEY (A, B, C). Suggest a simpler syntax for a CREATE TABLE declaration where the primary key and foreign key(s) are each single columns.

There is no NOT NULL clause on emp_no in the employee table. Can this column contain null?