relational algebra / data base

HW 2 - SQL

The database you will use for this assignment contains information related to Major League

Baseball (MLB) about players, teams, and games. The relations are:

Players(playerID, playerName, team, position, birthYear)

● playerID is a player identifier used in MLB, and all players throughout the history of

baseball have a unique ID

● playerName is player’s name

● team is the name of the MLB team the player is currently playing on (or the last team the

player played for if they are not currently playing)

● position is the position of the player

● birthYear is the year that player was born

Teams(teamID, teamName, home, leagueName)

● teamID is a unique ID internal to MLB.

● teamName is the name of the team

● home is the home city of the team

● leagueName is the league the team is in, i.e. either “National” or “American”, which

stands for “National League” and “American League”, respectively

Games(gameID, homeTeamID, guestTeamID, date)

● gameID is a unique ID used internally in MLB

● homeTeamID is the ID of the hometeam

● guestTeamID is the ID of the visiting team

● date is the date of the game.

A sample instance of this database is given at the end of this homework handout. Since it is just

one instance of the database designed to give you some intuition, you should not “customize”

your answer to work only with this instance.

1. (10 points each) Write the following queries in SQL, using the schema provided

above. (Note: Your queries must not be “state-dependent", that is, they should work without

modification even if another instance of the database is given.)

(a) Print the names of all players who were born in 1970 and played for the Braves.

(b) Print the names of teams that do not have a pitcher.

(c) Print names of all players who have played in the National League.

(d) Print all gameIDs with Phillies as the home team.

2. (15 points each) Write the following queries in SQL, using the schema provided

above.

(a) Print all teamIDs where the team played against the Phillies but not against the Braves.

(b) Print all tuples (playerID1, playerID2, team) where playerID1 and playerID2 are (or have

been) on the same team. Avoid listing self-references or duplicates, e.g. do not allow

(1,1,”Braves”) or both (2,5,”Phillies”) and (5,2,”Phillies”).

(c) Print all tuples (teamID1, league1, teamID2, league2, date) where teamID1 and teamID2

played against each other in a World Series game. Although there is no direct information

about the World Series games in the relations, we can infer that when two teams from different

leagues play each other, it is a World Series game. So, in this relation, league1 and league2

should be different leagues.

(d) List all cities that have a team in all leagues. For example, there are currently two leagues

(National and American). Although not shown in this instance, New York is home to the Mets in

the National league as well as the Yankees in the American league (Chicago also has one in

each league, for those of you who are baseball fans). Remember that your query must work

over all instances of this schema, even if there are more than two leagues in the instance.

Players

playerID playerName team position birthYear

1 Javy Lopez Braves Catcher 1970

2 Cliff Lee Phillies Pitcher 1978

3 Derek Jeter Yankees Infielder 1974

4 Skip Schumaker Cardinals Infielder 1980

5 Dominic Brown Phillies Outfielder 1987

Teams

teamID teamName home leagueName

1 Phillies Philadelphia National

2 Braves Atlanta National

3 Yankees New York American

4 Twins Minnesota American

5 Rangers Texas American

6 Cubs Chicago National

Games

gameID homeTeamID guestTeamID date

1 3 6 04/21/2010

2 1 4 04/21/2010

3 2 5 04/30/2010

4 6 3 05/02/2010

5 4 5 05/02/2010

6 1 5 05/06/2010