Hello friends,
I am just new to relational algebra probably a pre-step before learning SQL queries. Can you help me make the expressions of relational algebra expression for each of the following queries.
These are the tables contained inside a bus driver database.
1. Find the colors of bus reserved by Mark.
2. Find all IDs of drivers who have a rating of at least 7 or have reserved bus 112.
3. Find the names of drivers who have not reserved a yellow bus.
4. Find the IDs of drivers with age over 35 who have not reserved a blue bus.
I am just new to relational algebra probably a pre-step before learning SQL queries. Can you help me make the expressions of relational algebra expression for each of the following queries.
These are the tables contained inside a bus driver database.
- • driver( driver_id, driver_name, age, rating );
- • bus( bus_id, bus_name, color);
- • reserves( driver_id, bus_id, date);
1. Find the colors of bus reserved by Mark.
2. Find all IDs of drivers who have a rating of at least 7 or have reserved bus 112.
3. Find the names of drivers who have not reserved a yellow bus.
4. Find the IDs of drivers with age over 35 who have not reserved a blue bus.