Fields can be of different types. Some fields contain text, such as names. Other fields contain dates, such as date of birth. Other fields contain numbers, such as a person's height in centimeters. The structure of a database is composed of the various complex relations between entity files.
People interact as family members, as different roles in a human rights violation, etc.
People interact with organizations that they work in, that they are affiliated with, etc. These interactions are represented in the database by link structures. Link structures are discussed in more detail in the following section.