What's the difference in notation for total participation and recursive relation?
Does the double line in the following ER diagrams means total participation or recursive relation?
Could anyone tell me the notation difference for both?
Answer
Total Participation: Every entity in the set is involved in some association (or tuple) of the relationship.
Recursive Relationship: An entity set relating to itself.
Most commonly in recursive relationships they indicate the different types of roles an entity can have (e.g., the different ways it can participate) in a relationship by writing each role above each line.
An example of this would be in a Course table with a relational table of Prerequisites
A Course could be both the Prerequisite and the Course and you would write those on each line.
Here's another example.
Assuming your textbook follows a similar pattern, I would assume that these are in fact total participation constraints.