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# Cmis 320 Homework 2

Submitted By aymanskate
Words 326
Pages 2
Ayman Abdeldayem
CMIS 320

A piano manufacturer wants to track all pianos it makes. Each piano has a unique serial number and a manufacturing completion date. Each instrument represents exactly one piano model, all of which have an identification number and model. The company produces thousands of pianos of a certain model, and the design is specified before any single piano exists.

1. Identify the degree and cardinalities of the relationship.

The degree is the number of attributes in a relation. For this company, the attributes to distinguish between the products would be serial number, completion date, piano model, and identification number. This company makes thousands of pianos per model, and makes many different models. “Cardinality is the number of tuples in a relation,” in this case, a tuple would be a single piano model. So depending on the number of different piano models they produce will be the cardinality.

2. Express the relationships graphically with an E-R diagram.

A vendor builds multiple types of tablet computers. Each has a type, identification number, and a name. The key specifications for each type include amount of storage and display type. The company uses multiple processor types, exactly one of which is used for a specific tablet type. The same processor can be used in multiple types of tablets. Each processor has a manufacturer and a manufacturer's unique code that identifies it.

1. Identify the degree and cardinalities of the relationship.

The degree is the number of attributes in a relation. For this vendor, the attributes to distinguish between the tablets would be Identification number, name type, storage, display type, processor type, processor manufacturer, and manufacturer code. “Cardinality is the number of tuples in a relation,” in this case, a tuple would be a specific tablet model. So depending on the number of different tablet models available from this vendor is produced will be the cardinality.

2. Express the relationships graphically with an E-R diagram.

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