What kind of relational algebra operator would a LOAD keyword be mapped into? If it it's not a logical operator but only a physical one then how is it handled during the logical to physical operator transformation process by the database query processor? Or, if it's not mapped into relational algebra primitives is it then an implementation-specific relational algebra operator extention?
The LOAD keyword is internally mapped in the database after query parsing into a logical operator but it's not an algebra operator. All algebra operators are logical operators but not all logical operators are algebra operators.