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Chapter 7: Problem 31

Draw an ERD that allows for marriages between possibly more than two people.

Short Answer

Expert verified
The ERD will have two entities, 'Person' and 'Marriage', connected by a many-to-many relationship indicating that a person can participate in multiple marriages, and each marriage can have more than two participants.

Step by step solution

01

Define the Entities

Start by identifying the main entities in the system. In this case, the two entities will be 'Person' and 'Marriage'.
02

Define the Relationship

The relationship between 'Person' and 'Marriage' can be established in the form of 'A person participates in a marriage'. This relationship will be many-to-many, as one person can participate in more than one marriage and each marriage can have more than two participants.
03

Draw the ERD

In the ERD, 'Person' and 'Marriage' will be represented as entities, connected by a relationship. A many-to-many cardinality symbol would be used to represent the relationship between 'Person' and 'Marriage'.

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Most popular questions from this chapter

Consider the employee entity type. 1\. Suppose the company needs to track the names of dependents for each employee. Show the dependent name as a multi-valued attribute. 2\. Modify your ERD to show empDependentName as a composite multi-valued attribute comprising first and last names and middle initials.

A birthdate attribute would appear for many entity types – for example students, employees, children. What is a birthdate likely to be: key or non- key?

Consider an ERD for modelling customers, phones, and phone calls. Each customer owns one phone and so the phone number identifies the customer. Include other attributes such as credit card number, first name, and last name for a customer. We must record information for each phone call that is made: for each call there is a start time, end time, and of course the phone number/customers involved.

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