1. Propose a database schema that represents this information. Formally express the intention of each relationship schema, indicating the integrity constraints you think are necessary to complete its semantics.

2. Exemplify the extension of two of the relationships, one of them must define a referential constraint with respect to the other.

NOTE: Assume the existence of the predefined domains INTEGER, CHAR, REAL, STRING, DATE, etc.

1. COUNTRY: name, number of participants, number of medals.
2. ATHLETE: registration-ID, name, surnames, sex, country.
3. DISCIPLINE: identifier, name (e.g., 400M free swimming), discipline (e.g., swimming).
4. TEST: identifier, discipline, date, place, number of registered athletes, nature (eliminatory, final). For each discipline there are several eliminatory tests for a single final.
5. CLASSIFICATION: athlete, event, rank (e.g., 1, 2, ...).
6. RESULT: discipline, registration of the athlete with a gold medal, registration of the athlete with a silver medal, registration of the athlete with a bronze medal.

It is considered a relational database to manage the information of the Olympic games. Several hypotheses are made to simplify the problem and consider only a reduced subset of information:

• Only individual sports are considered.
• Only delegations from different countries and athletes are considered.