marcmajcher / killbase

Learn SQL with international assassins

Killbase

Killbase is a job board for international assassins. Assassins and their clients can register with Killbase, and enter or sign up for jobs. Assassins can have zero or more code names, and can sign up for any number of contracts; a contract may also be open to any number of assassins.

Assassins have:

• a full name
• zero or more codenames
• a weapon of choice
• contact information
• a minimum price they charge
• a float rating from 1-10
• number of kills
• an age

Contracts have:

• a target
• a client
• a budget (maximum price for the job)
• whether it's completed or not
• who completed it, if completed

Clients have:

• a name

Targets have:

• a name
• a location
• a photo
• a security level

Your tasks:

1. Create an entity relationship diagram for the tables in the Killbase database.
2. Create the killbase database, and write the SQL to create all the tables.
3. Write the SQL to seed the database with the following information:

Assassins

Full name	Code Names	Weapon	Age	Price	Rating	Kills
Alexander Duggan	The Jackal	Sniper rifle	31	45	7.5	28
Anton Chigurh	Old Man	Pneumatic bolt gun	52	40	9	72
	Ghost Dog	Pistol	28	20	6.5	35
Jason Bourne		Parkour	27	25	7	48
John Wick	Baba Yaga	Lots of guns	35	50	9.5	433
Jules Winnfield		Pistol	26	15	6.5	13
Leon	The Professional	Everything	41	30	8.5	87
Nikita Mears	Nikita, La Femme Nikita	Silenced pistols	28	30	7	32
Pickle Rick	Solenya	Lasers and office supplies	60	0	8	24

Contracts

Target Name	Target Location	Target Photo	Target Security	Client Name	Budget
Butch Coolidge	Los Angeles	https://goo.gl/LCquZj	3	Marcellus Wallace	40
The Jaguar	Russian Embassy	https://goo.gl/6JWsiv	9	Concerto	70
Norman Stansfield	Manhattan	https://i.imgur.com/mdIk33E.jpg	7	Mathilda	35
Santino D'Antonio	Continental Hotel	https://goo.gl/fUPkYy	10	Winston	25
Sonny Valerio	Queens	https://goo.gl/8DHYUS	4	Ray Vargo	10

(Hint: Create a text file with all the SQL commands to create and populate the table, then load it into psql.)

Exercises

1. Select all the assassins, sorted by number of kills.

2. Select all of the assassins older than 30 years old.

3. Select all of the contracts that can afford to pay Nikita Mears. (Budget >= her price)

4. Count the number of assassins that are capable of taking out Norman Stansfield. (Their rating >= his security level)

5. Get the total amount it would require to hire every available assassin.

6. Assign the following jobs to these assassins:

• Jules Winnfield -> Butch Coolidge
• The Jackal -> The Jaguar
• John Wick -> The Jaguar
• Leon -> Norman Stansfield
• Pickle Rick -> Sonny Valerio
• Jules Winnfield -> Santino D'Antonio
• Nikita Mears -> Norman Stansfield
• Ghost Dog -> Butch Coolidge

7. Count the number of currently contracted assassins.

8. Find the lowest total cost to complete all assigned contracts.

9. Add a new contract: Snake Plissken, New York, (find a photo), security 5, budget 35, Client is Marcellus Wallace.

10. Assign all assassins with a rate lower than the cost of the new contract to the new contract.

11. Complete these contracts: The Jaguar, by the Jackal; Butch Coolidge, by Ghost Dog; Snake Plissken, by Nikita Mears. (Be sure to increment the number of kills!)

12. Select all the completed contracts, showing only the assassins to be paid, and the amount paid to them. Then show the total cost of the completed contracts.

13. The Jackal has retired. Remove him from the database. (How can we do this while maintaining integrity on the contracts table?)

14. Ghost Dog and Nikita Mears have increased their rates by 5 and 10, respectively. Update their entries to reflect this.

15. The contract on Norman Stansfield has been rescinded. Remove it (and any associated data) from the database.

16. Winston has taken out a contract on John Wick! (Security 9, budget 100) We may have to rethink the way we're structuring our data. How can we refactor our database schema to allow a person to be an assassin, a client, or the target of a contract? Do that, then assign all assassins not already on a job to this new contract.