Quiz 2.docx

Section 2 Quiz (Answer all questions in this section) 1. A Unique Identifier has a NULL value for each instance of the entity for the lifetime of the instance. True or False

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True False (*) Correct 2. What is the purpose of a Unique Identifier?

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To identify a specific row within a table, using one or more columns and/or foreign keys. To identify one unique instance of an entity by using one or more attributes and/or relationships. (*) To uniquely determine a table and columns within that table. Create an entity that is unlike any other entity aside from itself. Correct 3. The physical model shows all table structures. True or False.

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True (*) False Correct 4. The logical model becomes the blueprint for designing the ________ model

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Physical (*) Network Data Integrity Data Flow Correct

5. Entities are usually _____________.

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Adjectives Nouns (*) Verbs Adverbs Correct

6. Entity names are always singular. True or False?

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True (*) False Correct 7. To identify an attribute as part of a unique identifier on an ER diagram, the # symbol goes in front of it. True or False?

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True (*) False Correct 8. Which of the following is not an advantage of a relational database?

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Efficiency Data Integrity One table with all the data. (*) Less Redundancy Correct

9. A table must have a primary key. True or False?

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True (*) False Incorrect. Refer to Section 2 Lesson 1. 10. Using ERDish, which wording represents optionality? (Choose Two)

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(Choose all correct answers) may (*) mandatory maybe must (*) Incorrect. Refer to Section 2 Lesson 6. Section 2 Quiz (Answer all questions in this section) 11. An ERD created using ERDish is a __________ representation of entities and their relationships to each other.

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graphical (*) textual hierarchical technical Correct 12. The conceptual model does all of the following except:

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Describes the needs of the business. Documents type of operating system to be used. (*) Takes into account regulations and laws goverining the industry being addressed. Prevents mistakes and misunderstandings.

Correct 13. Which of the following are true about Cardinality? (Choose two)

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(Choose all correct answers) Cardinality specifies only singularity or plurality, but not a specific plural number. (*) Cardinality tells "how many". (*) Cardinality specifies whether something is required or not. Cardinality specifies a counting number (like 1, 2, 3, 4 etc.) in a relationship. Correct 14. The optionality of a relationship must be either _______ or _______.

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Bidirectional or a single direction Mandatory or Optional (*) Single or Multiple One or (One or More) Correct 15. A __________ relationship is a relationship between an entity and itself.

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Recursive (*) Mandatory One to one Hierarchical Correct

1. Which of Mark for Review the (1) Points following is not a goal of

ER modeling: It is acceptable to include information that is derivable. (*) Ensure information appears only once. Locate information in a logical manner Capture all required information. Correct 2. A model is considered to be Implementation-Free if it can be implemented using ____ Mark for Review of the database software models such as hierarchical, network or relational. (1) Points any (*) only one none Correct 3. Which of the following statements about entity relationship diagrams (ERD) is true?

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Used to communicate the physical structure of the database to users. Used to communicate the logical structure of the database to users. (*) Is a hard and fast document that cannot be changed once development of the database has begun. Used to communicate the technical specifications of the database to users Incorrect. Refer to Section 2 Lesson 6. 4. A table must have a primary key. True or False?

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True (*) False Correct 5. Each column in a relation is called an entity. True or False?

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True False (*) Incorrect. Refer to Section 2 Lesson 1.

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In an ERD, optionality is depicted using __________.

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solid or dashed lines (*) single toe or crows foot names of relationships soft boxes

Correct

7.

The components of a relationship include all of the following except :

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Cardinality Optionality Relational Integrity (*) Names

Correct

8.

The optionality of a relationship must be either _______ or _______.

Bidirectional or a single direction One or (One or More) Mandatory or Optional (*) Single or Multiple

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Correct

9.

Which symbol is used to show that a particular attribute is mandatory?

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* (*) o & #

Correct

10.

Entities are usually _____________.

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Nouns (*) Verbs Adverbs Adjectives

Correct 11.

Entity names are always singular. True or False?

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True (*) False

Correct

12.

An ERD is an example of a ______ Model.

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Conceptual (*) Physical Data Integrity Network

Correct

13.

Which of the following are reasons we create conceptual models?

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It facilitates discussion; a picture is worth a thousand words It forms important ideal system documentation It takes into account government regulations and laws It forms a sound basis for physical database design All of the above (*)

Correct

14.

Unique Identifiers…

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Distinguish one entity from another. Distinguish one instance of an entity from all other instances of that entity (*) Distinguish all entities in a database Distinguish nothing

Correct

15.

A candidate UID that does not get chosen to become the primary UID is called a _________ .

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Secondary UID (*) Primary UID Composite UID Unique UID

Incorrect. Refer to Section 2 Lesson 4.

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Mark for Review 1. In a relationship (1) Points , _________ are used to helped describe the meaning of the connection between the entities. crows feet descriptions names (*) arrows Incorrect. Refer to Section 2 Lesson 5. 2. If a relationship is mandatory there must be at least one instance of the corresponding entity related to it. True (*) False

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Correct 3. One-to-One relationships have _____________ of one to one in both directions.

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Optionality Naming Foreign Keys Cardinality (*) Correct 4. Which of the following would be good as a Unique Identifier for its Entity? (Choose Three)

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(Choose all correct answers) Personal Identification number for Person (*) Date of birth for Baby ISBN Number for Book (*) Vehicle Registration Number for Car (*) Correct 5. A Unique Identifier has a NULL value for each instance of the entity for the lifetime of the instance. True or False True False (*) Correct

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Mark for Review 6. Flat file databases (1) Points are generally in plaintext form, where each line holds only one record. True or False?

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True (*) False Correct 7. A relational database stores information in tables with rows and columns.

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True (*) False Correct 8. The logical model becomes the blueprint for designing the ________ model

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Data Integrity Physical (*) Network Data Flow Correct 9. The logical model's entities, attributes, unique identifiers and relationships map to the Mark for Review physical model's _________________. (1) Points Optionality and Cardinality Tables, columns, primary keys and foreign keys (*) Files, records, fields and data values Correct 10. Using ERDish, which wording represents optionality? (Choose Two)

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(Choose all correct answers) mandatory maybe must (*) may (*) Correct

Previous 11.

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A model is considered to be ImplementationFree if it can be implemented using ____ of the database software models such as hierarchical, network or relational.

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any (*) only one none

Correct

12.

Which of the following statements about entity relationship diagrams (ERD) is true?

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Used to communicate the logical structure of the database to users. (*) Used to communicate the technical specifications of the database to users Is a hard and fast document that cannot be changed once development of the database has begun. Used to communicate the physical structure of the database to users.

Incorrect. Refer to Section 2 Lesson 6.

13.

To identify an attribute as part of a unique identifier on an ER diagram, the # symbol goes in front of it. True or False?

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True (*) False

Incorrect. Refer to Section 2 Lesson 3.

14.

Which of the following entities most likely contains invalid attributes?

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Entity: Mother. Attributes: Name, Birthdate, Occupation, Number of Children Entity: Pet. Attributes: Name, Birthdate, Owner Entity: Car. Attributes: Owner Occupation, Owner Salary, Speed (*) Entity: Home. Attributes: Number of Bedrooms, Owner, Address, Date Built

Correct

15.

An entity may have which of the following?

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Experiences Instances (*) Tables None of the above

Correct

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Summary