Gelinas-Dull_8e_TB_Chapter_06

Gelinas-Dull_8e_TB_Chapter_06 - Chapter 6Relational...

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Chapter 6—Relational Databases and SQL TRUE/FALSE 1. An entity in an accounting system can be classified as a resource, event or agent about which data are collected. ANS: T 2. Attributes are often called fields. ANS: T 3. A model is a complex representation of a simple entity or phenomenon. ANS: F 4. A primary attribute is the attribute whose value is unique for every entity that will appear in the data- base. ANS: F 5. The customer street address is often used as the key attribute in an REA diagram. ANS: F 6. In an REA diagram, the rectangle is used to represent the composite attribute. ANS: F 7. The first step in REA is evaluating the attributes. ANS: F 8. Relationships map and define the way in which data can be extracted from a database. ANS: T 9. A recursive relationship occurs between two different instances of an entity. ANS: T 10. Representing supervisors and their employees as separate entities in the model can lead to data redund- ancy. ANS: T 11. A recursive relationship is created when there is an employee being supervised, and another employee is the supervisor. ANS: T
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12. The cardinality constraint is used less frequently than the participation constraint. ANS: F 13. The cardinality constraint is used to specify both the minimum and maximum participation of one en- tity in the relationship with the other entity. ANS: F 14. The notation 1,N is used to specify the relationship type of one to many. ANS: T 15. The notation of (1,1) is used to specify the relationship type of one to many. ANS: F 16. REA stands for resources, entities and agents ANS: F 17. The fundamental requirement for moving toward an event driven model is the complete integration of data related to an organization’s business events. ANS: T 18. A legacy system is one that has existed in an organization for less than one year. ANS: F 19. A collection of data representing multiple occurrences of a resource, event, or agent is known as a rela- tion. ANS: T 20. A set of data that describes an instance of the entity represented by a relation is known as a tuple. ANS: T 21. A missing value is called a non-null. ANS: F 22. The secondary key is specified to uniquely identity each tuple in the relation. ANS: F 23. SQL is a powerful database language that can be used to define database systems, query the database for information, generate reports from the database, and access databases from within programs using embedded commands. ANS: T
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24. Relational integrity specifies that for every attribute in one relation that has been specified to allow ref- erence to another relation, the tuple being referenced must remain intact. ANS: F 25. A relation in an ER model is the same as an entity in the REA model. ANS: F
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This note was uploaded on 09/26/2011 for the course BA 101 taught by Professor Jackson during the Summer '06 term at University of Nevada, Las Vegas.

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Gelinas-Dull_8e_TB_Chapter_06 - Chapter 6Relational...

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