Podcast
Questions and Answers
What constraint specifies whether an entity in the higher-level entity set must belong to at least one of the lower-level entity sets within a generalization?
What constraint specifies whether an entity in the higher-level entity set must belong to at least one of the lower-level entity sets within a generalization?
Completeness constraint
How is an entity shown as belonging to only one lower-level entity set in an E-R diagram?
How is an entity shown as belonging to only one lower-level entity set in an E-R diagram?
Disjoint notation next to the ISA triangle
What does it mean when an entity can belong to more than one lower-level entity set in a specialization/generalization?
What does it mean when an entity can belong to more than one lower-level entity set in a specialization/generalization?
Overlapping
How can redundancy be eliminated in a situation where every manages relationship corresponds to a works_on relationship?
How can redundancy be eliminated in a situation where every manages relationship corresponds to a works_on relationship?
Signup and view all the answers
In E-R diagrams, what design decision allows for abstraction of relationships into new entities without introducing redundancy?
In E-R diagrams, what design decision allows for abstraction of relationships into new entities without introducing redundancy?
Signup and view all the answers
