I haven't been able to find information about the following issues, and would welcome pointers in the right direction.

- How does Dbman SQL actually store information about relations?
- What types of relations are supported?
- Is there currently a way to code relations between three tables? E.g. between the entries "John", "owner", "car" in the tables "Persons", "Functions", "Objects". The example might be stupid, but I need this for linguistic relationships, e.g. "text-passage X is an explanation of text-passage Y". Or is there a simpler way of implementing such relationships in relational databases? I'm currently doing this by adding an extra table with, in addition to the primary key, three keys, i.e. the primary keys of each of the three tables.


Thanks a lot in advance,
kellner