Oracle Mid Term

8/10/2019 Oracle Mid Term

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Test: Mid Term Exam Semester 1

Review your answers, feedback, and question scores below. An asterisk(*) indicates a correct answer.

Semester 1 Mid Term Exam covers Sections 1-10 of Database Design.

Section 10(Answer all questions in this section)

1. A datamodel containing generic modeling techniques must not bemixed in with non-generic models.The generic entities MUST be drawn on a diagram of their own. True orFalse? Mark for Review(1) Points

True

False (*)

Incorrect. Refer to Section 10 Lesson 2.

2. Generic models are generally far more complex than a specificmodel. True or False? Mark for Review(1) Points

True

False (*)


3. Which of the following statements are true for ERD's to enhancetheir readability. (Choose Two)Mark for Review(1) Points

(Choose all correct answers)

Is is OK to break a big ERD down into subsets of the overallpicture. This way you end up with more than one ERD,that together documents the entire system. (*)

Try to avoid crossing lines (*)


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The crows feet (many ends) can point whichever way is the easiestto draw

You must ensure you have all the entities on one single, bigdiagram, even if you have hundreds

Correct

4. There is no point in trying to group your entities together onyour diagram according to volume.Making a diagram pretty is a waste of time. True or False? Mark forReview(1) Points

True

False (*)



5. Which of the following is a logical constraint that could resultfrom considering how time impactsan example of data storage? Mark for Review(1) Points

An ASSIGNMENT may only refer to an EMPLOYEE with a valid employeerecord at the Start Date of the ASSIGNMENT. (*)

EMPLOYEE periods can overlap causing the database to crash.

End Date must be before the Start Date.

Dates must be stored with Time.

Correct

6. You are doing a data model for a computer sales company, wherethe price of postage is dependent onwhat day of the week goods are shipped. So shipping is more expensiveif the customer wants a delivery to


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take place on a Saturday or Sunday. What would be the best way tomodel this? Mark for Review(1) Points

Use a Delivery Day entity, which holds prices against week days,and ensure the we also have an attribute

for the Requested Delivery Day in the Order Entity. (*)

Email current price to all employees whenever the prices change.

Update the prices in the system, print out the current prices whenthey change and pin them onthe company noticeboard

Allow them to enter whatever ever delivery charge they want.

Correct

7. Modeling historical data is Optional. True or False? Mark forReview(1) Points

True (*)

False

Correct

8. When you add the concept of time to your data model, your modelbecomes more complex. True or False? Mark for Review(1) Points

True (*)

False

Correct

9. Which of the following would be a logical constraint whenmodeling time for a City entity? Mark for Review(1) Points

People are born in the city and people die in the city.

Cites may change their name and/or which country they are placedin, if the borders of a country change. (*)


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If you are doing a system for any French City, you would need

security clearance.

You need a constant record of cities because they are stillcities, even if leadership changes over time, e.g.

they get a new Mayor.



10. The first UID for an entity is called the Primary UID, the

second is called Secondary UID and so on.Mark for Review(1) Points

Yes, this is the way UID's are named. (*)

No, it is not possible to have more than one UID for an Entity.

Yes, but then it stops. No entities can have more than two UID's.

No, each Entity can only have one UID, the secondary one.

Correct

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1. A datamodel containing generic modeling techniques must not bemixed in with non-generic models. The generic entities MUST be drawnon a diagram of their own. True or False? Mark for Review

(1) Points

True

False (*)


2. Generic models are generally far more complex than a specificmodel. True or False? Mark for Review

(1) Points

True

False (*)


3. Which of the following statements are true for ERD's to enhancetheir readability. (Choose Two) Mark for Review(1) Points


Is is OK to break a big ERD down into subsets of the overallpicture. This way you end up with more than one ERD, that togetherdocuments the entire system. (*)

Try to avoid crossing lines (*)

The crows feet (many ends) can point whichever way is the easiestto draw

You must ensure you have all the entities on one single, bigdiagram, even if you have hundreds

Correct


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4. There is no point in trying to group your entities together onyour diagram according to volume. Making a diagram pretty is a wasteof time. True or False? Mark for Review(1) Points

True

False (*)



5. Which of the following is a logical constraint that could resultfrom considering how time impacts an example of data storage? Markfor Review(1) Points

An ASSIGNMENT may only refer to an EMPLOYEE with a valid employeerecord at the Start Date of the ASSIGNMENT. (*)

EMPLOYEE periods can overlap causing the database to crash.

End Date must be before the Start Date.

Dates must be stored with Time.

Correct

6. You are doing a data model for a computer sales company, wherethe price of postage is dependent on what day of the week goods areshipped. So shipping is more expensive if the customer wants adelivery to take place on a Saturday or Sunday. What would be the bestway to model this? Mark for Review(1) Points

Use a Delivery Day entity, which holds prices against week days,and ensure the we also have an attribute for the Requested DeliveryDay in the Order Entity. (*)

Email current price to all employees whenever the prices change.

Update the prices in the system, print out the current prices whenthey change and pin them on the company noticeboard


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Allow them to enter whatever ever delivery charge they want.

Correct

7. Modeling historical data is Optional. True or False? Mark forReview(1) Points

True (*)

False

Correct

8. When you add the concept of time to your data model, your modelbecomes more complex. True or False? Mark for Review(1) Points

True (*)

False

Correct

9. Which of the following would be a logical constraint whenmodeling time for a City entity? Mark for Review(1) Points

People are born in the city and people die in the city.

Cites may change their name and/or which country they are placedin, if the borders of a country change. (*)

If you are doing a system for any French City, you would needsecurity clearance.

You need a constant record of cities because they are still

cities, even if leadership changes over time, e.g. they get a newMayor.



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10. The first UID for an entity is called the Primary UID, thesecond is called Secondary UID and so on. Mark for Review(1) Points

Yes, this is the way UID's are named. (*)

No, it is not possible to have more than one UID for an Entity.

Yes, but then it stops. No entities can have more than two UID's.

No, each Entity can only have one UID, the secondary one.

Correct

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11. People are not born with "numbers", but a lot of systems assignstudent numbers, customer IDs, etc.A shoe has a color, a size, a style, but may not have a descriptive"number". So, to be able to uniquely and efficiently identify oneinstance of the entity SHOE, a/an ______________ UID can be created.

Mark for Review(1) Points

Artificial (*)

Unrealistic

Structured

Identification


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Correct

12. An entity without repeated values is said to be on 1st NormalForm. True or False? Mark for Review

(1) Points

True (*)

False

Correct

13. Normalizing an Entity to 1st Normal Form is done by removingrepeated or redundant attributes. True or False? Mark for Review

(1) Points

True (*)

False

Correct

14. Would it be a good idea to model age as an attribute ofSTUDENT? Mark for Review(1) Points

Yes

Maybe it could stop us having to calculate someone's age everytime we need it

Sometimes

No - it breaks the Normalization rules (*)


15. Any Non-UID must be dependant on the entire UID. True or False?Mark for Review(1) Points

True (*)

False


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Sometimes




True (*)

False

Correct

16. No commercial database systems in the world will accept tablesthat are not on 3rd Normal Form. True or False? Mark for Review(1) Points

True

False (*)



17. What do you call the entity created when you resolve a M:Mrelationship? Mark for Review(1) Points

Intersection entity (*)

Inclusion entity

Recursive entity

M:M entity


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Correct

18. Intersection Entities often have the relationshipsparticipating in the UID, so the relationships are

often barred. True or False? Mark for Review(1) Points

True (*)

False

Correct

19. When you resolve a M-M you simply re-draw the relationships

between the two original entities, no new entities are created. Trueor False? Mark for Review(1) Points

True

False (*)


20. If a relationship can NOT be moved between instances of theentities it connects, it is said to be: Mark for Review(1) Points

Mandatory

Optional

Transferrable

Non-Transferrable (*)


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11. People are not born with "numbers", but a lot of systems assignstudent numbers, customer IDs, etc.A shoe has a color, a size, a style, but may not have a descriptive"number". So, to be able to uniquely and efficiently identify oneinstance of the entity SHOE, a/an ______________ UID can be created.

Mark for Review(1) Points

Artificial (*)

Unrealistic

Structured

Identification

Correct

12. An entity without repeated values is said to be on 1st NormalForm. True or False? Mark for Review(1) Points

True (*)

False

Correct

13. Normalizing an Entity to 1st Normal Form is done by removingrepeated or redundant attributes. True or False? Mark for Review(1) Points

True (*)

False


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Correct

14. Would it be a good idea to model age as an attribute of

STUDENT? Mark for Review(1) Points

Yes


Sometimes




True (*)

False

Correct

16. No commercial database systems in the world will accept tablesthat are not on 3rd Normal Form. True or False? Mark for Review(1) Points

True

False (*)




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17. What do you call the entity created when you resolve a M:Mrelationship? Mark for Review(1) Points

Intersection entity (*)

Inclusion entity

Recursive entity

M:M entity

Correct

18. Intersection Entities often have the relationshipsparticipating in the UID, so the relationships are often barred. True

or False? Mark for Review(1) Points

True (*)

False

Correct

19. When you resolve a M-M you simply re-draw the relationshipsbetween the two original entities,no new entities are created. True or False? Mark for Review(1) Points

True

False (*)


20. If a relationship can NOT be moved between instances of the

entities it connects, it is said to be: Mark for Review(1) Points

Mandatory

Optional

Transferrable


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Non-Transferrable (*)


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21. A relationship from an entity back to itself is called a___________ relationship. Mark for Review(1) Points

Mandatory

Recursive (*)

Many to Many Optional

Transferrable


22. How do you include a relationship as part of the UID for anentity? Mark for Review(1) Points

By barring the relationship in question (*)

By reporting it in an external document


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By including the UID from the parent entity as an attribute in theentity

You cannot model that.

Correct

23. What uncommon relationship is described by the statements:"Each DNA SAMPLE may be taken from one and only onePERSON and each PERSON may provide one and only one DNA SAMPLE" Markfor Review(1) Points

One to Many Optional

One to Many Mandatory

One to One Optional (*)

Many to Many Mandatory


24. Relationships can be Redundant. True or False? Mark for Review(1) Points

True (*)

False

Correct


25. The "Other" subtype is mandatory. True or False? Mark forReview(1) Points

True

False (*)


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26. When creating entities you must follow these rules: (ChooseTwo) Mark for Review(1) Points


Name them in Plural

Name them in Singular (*)

Exclude Attributes

Include Attributes (*)


27. All ER diagrams must have one of each of the following: (Choosetwo) Mark for Review(1) Points


One or more Entities (*)

Relationships between entities (*)

Arcs

At least one supertype and subtype

Correct

28. Which of the following is true about subtypes? Mark for Review(1) Points

One instance may belong to two subtypes of the same supertype.

Subtypes must be mutually exclusive. (*)

Subtypes must not be mutually exclusive.

Subtype entities may not have relationships to the other subtypeentities, only the supertype itself.


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31. A recursive relationship must Mandatory at both ends. True or

False? Mark for Review(1) Points

True

False (*)


32. Which of the following would best be represented by an arc?Mark for Review(1) Points

TEACHER (Female, Bob)

DELIVERY ADDRESS (Home, Office) (*)

PARENT (Girl, Bob)

STUDENT (Grade A student, Average Student)


33. All relationships participating in an arc must be mandatory.True or False? Mark for Review(1) Points

True

False (*)


34. Arcs are used to visually represent _________ between two ormore relationships in an ERD. Mark for Review

(1) Points

Sameness

Differences

Exclusivity (*)

Inheritance


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39. To identify an attribute as part of a unique identifier on anER diagram, the # symbol goes in front of it. True or False? Mark forReview(1) Points

True (*)

False

Correct

40. Matrix Diagrams are used to verify an ERD. True or False? Markfor Review(1) Points

True (*)

False

Correct

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45. Data modelling is performed for the following reasons: (Choose

Two) Mark for Review(1) Points


The ERD's becomes a blueprint for designing the actual system. (*)

It helps discussions and reviews. (*)

We do not need datamodels, we can just start coding right away.

We just draw the ERD's to please the users, once they are finishedwe never look at them again. They serve no purpose in the real world.

Correct

46. Relationship names are usually verbs. True or False? Mark forReview(1) Points

True (*)

False

Correct

47. Which of the following entities most likely contains validattributes? (Choose two) Mark for Review(1) Points


Entity: Home. Attributes: Number of Bedrooms, Owner, Address, DateBuilt (*)

Entity: Pet. Attributes: Name, Birthdate, Owner (*)

Entity: Car. Attributes: Owner Occupation, Owner Salary, Speed

Entity: Mother. Attributes: Name, Birthdate, Occupation, Salary

Correct


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48. All of the following would be instances of the entity ANIMALSPECIES except which? Mark for Review(1) Points

Dog

Bird

Elephant

Leaf (*)


49. An entity can have many Unique Identifiers. True or False?Mark for Review

(1) Points

True (*)

False

Correct

50. Which of the following statements about relationships are true?(Choose Two) Mark for Review(1) Points


They become foreign keys in the database. (*)

They must be mandatory to be created in the database.

They can be either mandatory or optional. (*)

They must exist between two different Entities.


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