Understanding Data Relationships
By Dale E. Lee
The prior article on Understanding Data was written from the standpoint of Family History data stored on a computer and how it can be displayed out to the user. This article is written from the standpoint of entering Family History data into a computer and how it is stored in the computer.
When a user enters data into a computer, cell phone, or other device, it is normally presented on the screen in a user friendly manner so that the data and the relationships are intuitive. However, when the data is stored in the computer it has to meet strict computer standards or bad things can happen, such as retrieval of incorrect data, or an unacceptable amount of time to store and retrieve the data.
In the diagram below, the left side of the image shows the view of the data from the standpoint of a computer screen. You can see that there is an individual which has a Mother and a Father as well as two children. These should have been labeled with their real names, such as Bob, Beth, Rick, etc., but the way I labeled them this way to make the relationships very clear. In addition to names, other information will normally be entered, such as date and place of birth, date and place of death, etc.
The right side of the diagram shows that the information on the computer screen is extracted, split up and stored in records on the computer. Family History data can be stored in many different ways depending on the developer, but I am showing the simplest method to do so. The computer assigns ID’s to each individual and these are used to help it understand relationships between individuals.
The top portion of the right side of the diagram shows that each person and each relationship is stored on a separate record. Information on all of the individuals, whether Father, Mother, Spouse, etc. is stored on a Person Record. Relationships between two people are stored in the Relation record using the individual ID’s of the two people involved in the relationship.
The lower portion of the right side shows detailed information about what is stored on the records. The Person Detail record stores a person’s ID, name, Birth data and place, Death date and place, etc. The Relationship detail stores the two IDs for the individuals in the relationship.
Using the records on the Person Detail table and the Relationship Detail table, the computer can reassemble the original data entered in the computer screen and display it back to the screen as it was originally entered. In addition, it can use the data and relationships to produce reports and charts that may look different than the original, but which show data that is correct and consistent with the original data entered, such as descendant charts, fan charts, network charts, etc.
If the data model was designed properly, the data can be used for things that were not originally considered in the design itself because the data is consistent and has integrity. Knowing how the data is stored you can get an idea of the kinds of things you can use it for in your genealogical efforts in the future.
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