michigan informatics

Displaying Relationships

Using multiple related tables helps keep table sizes small, and data more manageable. If we tried to do the same thing with just one table, we would need distinct fields for each contact. For example, we might have contactDate1, contactType1, contactSuccess1, contactDate2, contactType2, contactSuccess2, and so on.

The black line (1) between the two tables shows that there is a relationship between them. This relationship is between the ID field in the participants table and the participantID field in the contacts table. The infinity symbol (2)  next to the contacts table shows that this relationship is one-to-many. In other words, each record in the participants table corresponds with many records in the contacts table.