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Entity Types and Relationships

There are many kinds of entity relationships in a database model. The relationships can be classified by the following things.

Cardinality: maximum and minimum
Degree: binary, ternary, degree 4, and so forth
Entity type: strong, weak, ID-dependent, and supertype/subtype

What are these different types of classifications? Do they overlap, or do they each tell us something unique about the entity relationship? Why is it important to classify each of these types in an ERD (entity relationship diagram) model?

Solution Preview

Kindly find the enclosed document for the solution.

An entity-relationship model, a graphical representation of entities and their relationships to each other, is typically used in computing in regard to the organization of data within databases or information systems. An entity is a piece of data, an object or concept about which data is stored. A relationship on the other hand is how the data is shared between entities.

The basic types of connectivity for entity relations are:
- one-to-one,
- one-to-many,
- and many-to-many.

Each of them tells us about ...

Solution Summary

The basic types of connectivity for entity relations are:
- one-to-one,
- one-to-many,
- and many-to-many.

Each of them tells us about the unique feature of connectivity that they have among the entities in an ERD. This idea is illustrated with the example in given solution.

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