--- title: "ER diagram: cricket tournament" subject: "Database Management System" chapter: 2 key: "semester_6/database_management_system:er-cricket-tournament" source: https://www.bctengineer.com/q/semester_6/database_management_system/er-cricket-tournament site: BCT Engineering --- # ER diagram: cricket tournament Database Management System · Chapter 2: Data Models - Asked in: 2072 Magh - Answer checked by Claude Opus 5.5 (high effort) on 2026-10-14 - Page: https://www.bctengineer.com/q/semester_6/database_management_system/er-cricket-tournament - Whole chapter: https://www.bctengineer.com/md/semester_6/database_management_system/chapter-2 ## Question Draw an ER diagram for a cricket tournament. [The question text is not printed; the page gives only the label and the solution diagram: Team participates in Tournament (10 teams : 1 tournament); two teams play a Match (Match has attribute Date); a Match has 3 Referees; a Match is played on one Ground (Ground has attributes seat_capacity and size); Players (attributes run_scored, wicket_taken) and Member (attributes role, experience) are ISA specializations of Team.] ## Short answer Entities: Tournament, Team, Match, Referee, Ground, and ISA specializations Member (role, experience) and Player (run_scored, wicket_taken). Relationships: Team participates in Tournament (N:1), two teams play Match (M:N), Match has 3 Referees (1:3), Match played on one Ground (N:1). ## Answer An ER diagram models the entities, attributes and relationships of the tournament. The assumptions below follow the usual cricket set-up. #### Entities and attributes - **Tournament** (t_id, name): the competition. - **Team** (team_id, name): about 10 teams take part in one tournament. - **Match** (match_no, *date*): played between two teams. - **Referee** (ref_id, name): each match has 3 referees. - **Ground** (ground_id, name, *seat_capacity*, *size*): each match is played on one ground. - **Member** (*role*, *experience*) and **Player** (*run_scored*, *wicket_taken*): ISA specializations of Team, as drawn in the given solution (a team is made up of players and other members such as the coach or manager). #### Relationships - Team **participates in** Tournament: N : 1 (10 teams to 1 tournament). - Team **plays** Match: M : N (exactly 2 teams per match). - Match **has** Referee: 1 : 3. - Match **played on** Ground: N : 1. - Player and Member are subclasses (ISA) of Team. #### ER diagram ```text [Tournament] | 1 | N [Team]-----2----- | | N ISA | / \ | [Member] [Player] | | [Referee]--3--------1-------[Match]--N----1--[Ground] (date) (seat_capacity, size) Member: role, experience Player: run_scored, wicket_taken ``` In the diagram, rectangles are entities, diamonds (shown as <...>) are relationships, and the ISA triangle shows that Member and Player inherit the attributes of the superclass. Each number is written next to the entity it counts: for example, 3 referees per match, 2 teams per match and 10 (N) teams per tournament. ## Check yourself The answer's key points as multiple-choice questions, with the correct option and why. 1. In the cricket ER diagram, what is the cardinality of 'Team participates in Tournament'? A. 1 : N, one team in many tournaments B. M : N, since teams play each other C. 1 : 1, one team per tournament D. N : 1, about 10 teams to 1 tournament Answer: D. About 10 teams take part in one tournament, so many teams map to one tournament (N : 1). (Key point: Cardinality Team-Tournament) 2. How is the relationship between Team and Match modelled? A. 1 : N, one team plays only one match B. M : N, with exactly 2 teams per match C. N : 1, many teams in a single match always D. 1 : 1, one team per match Answer: B. A team plays many matches and a match involves two teams, so the relationship is M : N. (Key point: Team plays Match) 3. Why are Player and Member drawn under Team with an ISA triangle? A. They are weak entities that cannot exist without a Match B. They are relationships between Team and Tournament C. They replace the Team entity, which is then deleted D. They are subclasses that inherit Team's attributes and add their own (e.g. run_scored, role) Answer: D. ISA shows specialization: subclasses inherit the superclass attributes and add specific ones. (Key point: ISA specialization) 4. Which pair of relationships is correct for Match? A. Match has 1 Referee (1 : 1); Match is played on many Grounds (1 : N) B. Match has 3 Referees (1 : 3); Match is played on one Ground (N : 1) C. Match has 3 Referees (M : N); Match is played on 3 Grounds D. Match has 2 Referees; Match is played on one Ground (1 : 1) Answer: B. Each match has 3 referees, and many matches can be held on the same ground, so Match-Ground is N : 1. 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