Continuing with some guidelines that they have given me, I have a doubt about the relationship between some entities, they tell me the following:
You want to store information about the athletes who participate in the different tests. Each athlete will be assigned a unique alphanumeric code, name and surname, date of birth, sex and nationality. Each athlete who participates in a test can do so individually or representing a club, which may be different for each test in which they participate. Every club, as the entity that it is, is identified by an alphanumeric code and is assigned a name and, possibly, a web page. In addition, for the clubs we want to store the location of their headquarters by means of their coordinates (longitude and latitude). After the participation of the athletes in the different tests, it is desired to record the number with which they have competed, the position in which they have been classified and the mark or result obtained.
I have set it up as follows:
The issue is that I had the doubt of entering a ternary relationship between the entity "test","athletes" and "club" and in turn associating these to an associative entity with the results obtained by the athlete.
Maybe it's all simpler than how I put it but I have doubts.
I would model the semantics that you define like this, because I don't see a particularly stable link between an athlete and his club either. If so, it would add an additional relationship
representan
between clubs and athletes, but it seems that athletes only represent clubs in specific events. Results and assigned numbers do not need to be modeled as a separate entity, they can be attributes of the relationshipcompiten
.