WorksheetsDatabase Design Learner
Total questions: 67
Worksheet time: 1hrs 6mins
To convert an entity with a multi valued attribute to 1st Normal Form, we create an additional entity and relate it to the original entity with a 1:1 relationship. True or False?
True
False
When data is only stored in one place in a database, the database conforms to the rules of ___________.
Reduction
Normalization
Multiplication
Normality
Normalizing an Entity to 1st Normal Form is done by removing any attributes that contain muliple values. True or False?
True
False
An attribute can have multiple values and still be in 1st Normal Form. True or False?
True
False
The Rule of 3rd Normal Form states that No Non-UID attribute can be dependent on another non-UID attribute. True or False?
True
False
Examine the following Entity and decide which rule of Normal Form is being violated:
ENTITY: CLIENT
ATTRIBUTES:
# CLIENT ID
FIRST NAME
LAST NAME
ORDER ID
STREET
1st Normal Form
2nd Normal Form
3rd Normal Form
None of the above, the entity is fully normalised.
Examine the following Entity and decide which sets of attributes break the 3rd Normal Form rule:
ENTITY: TRAIN
ATTRIBUTES:
TRAIN ID
MAKE
DRIVER ID
DRIVER NAME
DATE OF MANUFACTURE
TRAIN ID, MAKE
DRIVER ID, DRIVER NAME
MAKE, DATE OF MANUFACTURE
None of the above, the entity is already in 3rd Normal Form
As a database designer, you do not need to worry about where in the datamodel you store a particular attribute; as long as you get it onto the ERD, your job is done. True or False?
True
False
If an entity has no attribute suitable to be a Primary UID, we can create an artificial one. True or False?
True
False
People are not born with 'numbers', but a lot of systems assign student numbers, customer IDs, etc. ﾠThese are known as a/an ______________ UID.
Unrealistic
Structured
Identification
Artificial
Which of the following would be suitable UIDs for the entity EMPLOYEE: (Choose Two)
Address
Employee ID
Last Name
Social Security Number
The candidate UID that is chosen to identify an entity is called the Primary UID; other candidate UIDs are called Secondary UIDs.
No, each Entity can only have one UID, the secondary one.
Yes, this is the way UID's are named.
No, it is not possible to have more than one UID for an Entity.
No, after UIDs are first sorted, the first one is called the Primary UID, the second is the Secondary UID, etc.
Examine the following entity and decide which attribute breaks the 2nd Normal Form rule:
ENTITY: CLASS
ATTRIBUTES:
#CLASS ID
#TEACHER ID
SUBJECT
TEACHER NAME
CLASS ID
SUBJECT
TEACHER ID
TEACHER NAME
To resolve a 2nd Normal Form violation, we:
Delete the attribute that was causing the violation.
Do nothing, an entity does not need to be in 2nd Normal Form.
Move the attribute that violates 2nd Normal Form to a new entity with a relationship to the original entity.
Move the attribute that violates 2nd Normal Form to a new ERD.
Any Non-UID attribute must be dependent upon the entire UID. True or False?
True
False
When is an entity in 2nd Normal Form?
When all non-UID attributes are dependent upon the entire UID.
When attributes with repeating or multi-values are present.
When no attributes are mutually independent and all are fully dependent on the primary key.
None of the Above.
Examine the following entity and decide how to make it conform to the rule of 2nd Normal Form:
ENTITY: RECEIPT
ATTRIBUTES:
#CUSTOMER ID
#STORE ID
STORE LOCATION
DATE
Move the attribute STORE LOCATION to a new entity, STORE, with a UID of STORE LOCATION, and create a relationship to the original entity.
Delete the attribute STORE ID
Move the attribute STORE LOCATION to a new entity, STORE, with a UID of STORE ID, and create a relationship to the original entity.
Do nothing, it is already in 2nd Normal Form.
A unique identifier can only be made up of one attribute. True or False?
True
False
An entity can only have one Primary UID. True or False?
True
False
A candidate UID that is not chosen to be the Primary UID is called:
Artificial
Composite
Simple
Secondary
A UID can be made up from the following:
(Choose Two)
Relationships
Synonyms
Attributes
Entities
When all attributes are single-valued, the database model is said to conform to:
4th Normal Form
3rd Normal Form
1st Normal Form
2nd Normal Form
An attribute can have multiple values and still be in 1st Normal Form. True or False?
True
False
When data is stored in more than one place in a database, the database violates the rules of ___________.
Normalization
Decency
Normalcy
Replication
Examine the following Entity and decide which rule of Normal Form is being violated:
ENTITY: CLIENT ORDER
ATTRIBUTES:
# CLIENT ID
# ORDER ID
FIRST NAME
LAST NAME
ORDER DATE
CITY
1st Normal Form
2nd Normal Form
3rd Normal Form
None of the above, the entity is fully normalised.
Examine the following Entity and decide which rule of Normal Form is being violated:
ENTITY: CLIENT
ATTRIBUTES:
# CLIENT ID
FIRST NAME
LAST NAME
STREET
CITY
1st Normal Form
2nd Normal Form
3rd Normal Form
None of the above, the entity is fully normalised.
A transitive dependency exists when any attribute in an entity is dependent on any other non-UID attribute in that entity.
True
False
What is the rule of Second Normal Form?
No non-UID attributes can be dependent on any part of the UID.
Some non-UID attributes can be dependent on the entire UID.
All non-UID attributes must be dependent upon the entire UID
None of the above
To resolve a 2nd Normal Form violation, we:
Do nothing, an entity does not need to be in 2nd Normal Form.
Move the attribute that violates 2nd Normal Form to a new entity with a relationship to the original entity.
Delete the attribute that was causing the violation.
Move the attribute that violates 2nd Normal Form to a new ERD.
An entity could have more than one attribute that would be a suitable Primary UID. True or False?
True
False
There is no limit to how many attributes can make up an entity's UID. True or False?
True
False
If an entity has a multi-valued attribute, to conform to the rule of 1st Normal Form we:
Make the attribute optional
Create an additional entity and relate it to the original entity with a M:M relationship.
Do nothing, an entity does not have to be in 1st Normal Form
Create an additional entity and relate it to the original entity with a 1:M relationship.
Where an entity has more than one attribute suitable to be the Primary UID, these are known as _____________ UIDs.
Secondary
Composite
Candidate
Simple
Examine the following entity and decide which attribute breaks the 2nd Normal Form rule:
ENTITY: RECEIPT
ATTRIBUTES:
#CUSTOMER ID
#STORE ID
STORE LOCATION
DATE
STORE ID
CUSTOMER ID
STORE LOCATION
DATE
To visually represent exclusivity between two or more relationships in an ERD you would most likely use an ________.
Relationship
Attribute
UID
Arc
Arcs model an Exclusive OR constraint. True or False?
True
False
Every business has restrictions on which attribute values and which relationships are allowed. These are known as:
Entities
Relationships
Attributes
Constraints
An arc can often be modeled as Supertype and Subtypes. True or False?
True
False
Which of the following can be added to a relationship?
An optional attribute can be created
An attribute
An arc can be assigned
A composite attribute
Arcs are used to visually represent _________ between two or more relationships in an ERD.
Inheritance
Exclusivity
Sameness
Differences
Which of the following would best be represented by an arc?
STUDENT(University, Technical College)
STUDENT(Grade A Student, Average Student)
STUDENT(senior, male)
STUDENT(graduating, female)
All relationships participating in an arc must be mandatory. True or False?
True
False
A recursive relationship must be Mandatory at both ends. True or False?
True
False
A Recursive Relationship is represented on an ERD by a/an:
Single Toe
Pig's Ear
Crow's Foot
Dog's Tail
A single relationship can be both Recursive and Hierarchical at the same time. True or False?
True
False
A Hierarchical relationship is a series of relationships that reflect entities organized into successive levels. True or False?
True
False
A relationship between an entity and itself is called a/an:
Invalid Relationship
Recursive Relationship
General Relationship
Hierarchical Relationship
A particular problem may be solved using either a Recursive Relationship or a Hierarchical Relationship, though not at the same time. True or False?
True
False
Cascading UIDs are a feature often found in what type of Relationship?
Recursive Relationship
General Relationship
Invalid Relationship
Hierarchical Relationship
Business organizational charts are often modeled as a Hierarchical relationship. True or False?
True
False
Arcs are Mandatory in Data modeling. All ERD's must have at least one Arc. True or False?
True
False
Which of the following would best be represented by an arc?
DELIVERY ADDRESS(Home, Office)
STUDENT(Grade A Student, Average Student)
PARENT(Girl, Bob)
TEACHER(Female, Bob)
Conditional non-transferability refers to a relationship that may or may not be transferable, depending on time. True or False?
True
False
In a payroll system, it is desirable to have an entity called DAY with a holiday attribute when you want to track special holiday dates. True or False?
True
False
When a relationship may or may not be transferable, depending on time, this is know as a/an:
Arc
Transferable Relationship
Non-transferable Relationship
Conditional Non-transferable Relationship
All systems must have an entity called WEEK with a holiday attribute so that you know when to give employees a holiday. True or False?
True
False
How do you know when to use the different types of time in your design?
The rules are fixed and should be followed.
You would first determine the existence of the concept of time and map it against the Greenwich Mean Time.
Always model time; you can take it out later if it is not needed.
It depends on the functional needs of the system.
Why would you want to model a time component when designing a system that lets people buy bars of gold?
The price of gold fluctuates and, to determine the current price, you need to know the time of purchase.
You would not want to model this; it is not important.
The Government of your country might want to be notified of this transaction.
Sales people must determine where the gold is coming from.
You are doing a data model for a computer sales company where the price of postage depends upon the day of the week that goods are shipped. So shipping is more expensive if the customer wants a delivery to take place on a Saturday or Sunday. What would be the best way to model this?
Allow them to enter whatever delivery charge they want.
Update the prices in the system, print out the current prices when they change, and pin them on the company noticeboard.
Email current prices to all employees whenever a price changes.
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.
You are doing a data model for a computer sales company where the price fluctuates on a regular basis. If you want to allow the company to modify the price and keep track of the changes, what is the best way to model this?
A. Create a product entity and a related price entity with start and end dates, and then let the users enter the new price whenever required.
B. Create a new item and a new price every day.
C. Use a price entity with a start and end date.
D. Allow them to delete the item and enter a new one.
E. Both A and C.
Modeling historical data can produce a unique identifier that includes a date. True or False?
True
False
Which of the following scenarios should be modeled so that historical data is kept? (Choose two)
CUSTOMER and PAYMENTS
CUSTOMER and ORDERS
TEACHER and AGE
BABY and AGE
Which of the following scenarios should be modeled so that historical data is kept? (Choose two)
LIBRARY and BOOK
STUDENT and AGE
LIBRARY and NUMBER OF BOOKS
STUDENT and GRADE
No formal rules exist for drawing ERD's. The most important thing is to make sure that all entities, attributes, and relationships are documented on the diagram, and the diagram is clear and readable. True or False?
True
False
Which of the following statements are true for ERD's to enhance their readability. (Choose Two)
The crows feet (many ends) can point whichever way is the easiest to draw.
Avoid crossing one relationship line with another.
You must ensure that you have every single entity--even if hundreds of them exist--on one single, big diagram.
It is OK to break down a large ERD into subsets of the overall picture. By doing so, you end up with more than one ERD that, taken together, documents the entire system.
There is no point in trying to group your entities together on your diagram according to volume, and making a diagram look nice is a waste of time. True or False?
True
False
In an ERD, High Volume Entities usually have very few relationships to other entities. True or False?
True
False
