Database Design Section 1-5 Exam Study Guide

Which symbol is used to show that a particular attribute is mandatory? -o -* -# -&

-*

If a relationship can NOT be moved between instances of the entities it connects, it is said to be: -Mandatory -Transferable -Optional -Non-Transferable

-Non-Transferable

Which of the following attributes is suitable to be a Unique Identifier? -Address -Last name -First name -Social Security Number

-Social Security Number

A subtype is drawn on an ERD as an entity inside the "softbox" of the supertype. True or False?

-True

Which of the following can be found in an ERD? (Choose Two)(Choose all correct answers) -Attributes. -Instances. -Entities. -Tables.

-Attributes. -Entities.

The main subject areas taught by the Oracle Academy are: -Data Modeling, SQL, and PL/SQL -Computer Repairs -Database performance tuning -Systems programming and computer architecture

-Data Modeling, SQL, and PL/SQL

What is the difference between "information" and "data"? -Data turns into useful information. It is stored in a database and accessed by systems and users. -Information and data have no differences - they are two words for the same thing. -Information is held and understood only by users. -Data is held and understood only by users.

-Data turns into useful information. It is stored in a database and accessed by systems and users.

A non-transferable relationship is represented by which of the following symbols? -Circle -Triangle -Heart -Diamond

-Diamond

A non-transferable relationship means the relationship is manatory at both sides. True or False?

-False

Personal computers (PCs) have been in existence since 1950. True or False?

-False

A subtype is shown on an ERD as an entity with a one to many relationship to the supertype. True or False?

-False

All instances of a subtype may be an instance of the supertype but does not have to. True or False?

-False

An ERD is an example of a Physical Model. True or False?

-False

A new system would have a mixture of both Procedural and Structural Business Rules as part of the documentation of that new system. True or False?

-True

A subtype can have a relationship not shared by the supertype. True or False?

-True

Data models show users the data that their Physical Model will contain. True or False?

-True

Relationship Cardinality is important. True or False?

-True

When reading a relationship between 2 entities, the relationship is read both from left to right and right to left. True or False?

-True

In the following statements, find two good examples of ENTITY: Instance. (Choose Two)(Choose all correct answers) -BOOK: Biography of Mahatma Gandhi -VEGETABLE: grows -TRAIN: runs -DAIRY PRODUCT: milk

-BOOK: Biography of Mahatma Gandhi -DAIRY PRODUCT: milk

If an intersection entity is formed that contains no attributes of its own, its uniqueness may be modeled by -Creating new attributes. -Barring the relationships to the original entities. -Placing the UID attributes from the original entities into the intersection entity. -None of the above.

-Barring the relationships to the original entities.

Why is it important to identify and document structural rules? -Ensures we know what data to store and how that data works together. -Ensures nothing. There are no benefits to be gained from documenting your Structural Business Rules. We need to concentrate on the Procedural Business Rules only. -Ensures we know what processes are in place and how to program them. -All of the Above.

-Ensures we know what data to store and how that data works together.

An Entity Relationship model is independent of the hardware or software used for implementation. True or False?

-True

Data models are drawn to show users the actual Data that their new system will contain; only Data listed on the Diagram can be entered into the Database. True or False?

-True

Databases are used in most countries and by most governments. Life, as we know it, would change drastically if we no longer had access to databases. True or False?

-True

Documenting Business Requirements helps developers control the scope of the system and prevents users from claiming that the new system does not meet their business requirements. True or False?

-True

Entities are transformed into Tables during the Database Design process. True or False?

-True

In the grid computing model, resources are pooled together for efficiency. True or False?

-True

Matrix Diagrams are developed BEFORE the ERD. True or False?

-True

Oracle was one of the first relational database systems available commercially. True or False?

-True

Changes in computing have affected many of our day-to-day activities. Are all of the following activities examples of this change? Yes or No? In the past you used to use the phone system to call directory assistance to get a phone number. Today you can use your PC to look up a phone number online. In the past you used to have to go to the shoe store to buy shoes. Today you can use your PC to order shoes online. In the past you had to use your PC to send a person an email. Today you can use your phone to send a text message.

-Yes

Which of the following statements are true about ERD's? (Choose Two) (Choose all correct answers) -You should not model derivable data. -A piece of information can be shown multiple times on an ERD. -A piece of information should only be found in one place on an ERD. -All data must be represented on the ERD, including derived summaries and the result of

-You should not model derivable data. -A piece of information should only be found in one place on an ERD.

When you resolve a M:M by creating an intersection entity, this new entity will always inherit: -The UID's from the entities in the original M:M. -The attributes of both related entities. -A relationship to each entity from the original M:M. -Nothing is inherited from the original entities and relationship.

-A relationship to each entity from the original M:M.

Which of the following is an example of a volatile attribute? -Hire Date -Name -Date of Birth -Age

-Age

Which of the following entities most likely contains valid attributes? (Choose two)(Choose all correct answers) -Entity: Home. Attributes: Number of Bedrooms, Owner, Address, Date Built -Entity: Pet. Attributes: Name, Birthdate, Owner -Entity: Car. Attributes: Owner Occupation, Owner Salary, Speed -Entity: Mother. Attributes: Name, Birthdate, Occupation, Start Date

-Entity: Home. Attributes: Number of Bedrooms, Owner, Address, Date Built -Entity: Pet. Attributes: Name, Birthdate, Owner

Matrix Diagrams show Optionality and Cardinality of the ERDs they document. True or False?

-False

Relationship names are not shown on an ERD. True or False?

-False

The overall mission of the Oracle Corporation is to use the internet and fast processing servers to build its own network. True or False?

-False

When you resolve a M:M, you simply re-draw the relationships between the two original entities; no new entities are created. True or False?

-False

Consider your school library. It will have a database with transaction details of the books that are borrowed by students. Is the total number of books out on loan in one given month considered Data or Information? -Data -Information -Both -Neither

-Information

Why is it important to identify and document business rules? -It allows you to create a complete data model -and then check it for accuracy. -It allows you to improve the client's business. -It ensures that the data model will automate all manual processes. -None of the above

-It allows you to create a complete data model -and then check it for accuracy.

How should you handle constraints that cannot be modeled on an ER diagram? -Explain them to the users so they can enforce them -Always let the network architect handle them -List them on a separate document to be handled programmatically -All constraints must be modeled and shown on the ER diagram

-List them on a separate document to be handled programmatically

What are the three properties that every relationship should have? -Transferability, degree, name -Name, optionality, cardinality -Name, optionality, arcs -A UID bar, a diamond, an arc

-Name, optionality, cardinality

All of the following could be attributes of an ENTITY called PERSON, except which one? -Gender -Natacha Hansen -Weight -Haircolor

-Natacha Hansen

All ER diagrams must have one of each of the following: (Choose two)(Choose all correct answers) -At least one supertype and subtype -One or more Entities -Relationships between entities -Arcs

-One or more Entities -Relationships between entities

What uncommon relationship is described by the statements: "Each DNA SAMPLE may be taken from one and only one PERSON and each PERSON may provide one and only one DNA SAMPLE" -Many to Many Mandatory -One to Many Optional -One to Many Mandatory -One to One Optional

-One to One Optional

If the same relationship is represented twice in an Entity Relationship Model, it is said to be: -Removable -Resourceful -Redundant -Replicated

-Redundant

If two entities have two relationships between them, these relationships can be either _____________ or _____________. -Redundant or Required -Replicated or Required -Resourced and Really Good -Redundant and Replicated

-Redundant or Required

Which of the following are used to show Cardinality on an ERD? (Choose two)(Choose all correct answers) -Dashed line. -Single toe. -Crow's foot. -Solid line.

-Single toe. -Crow's foot.

Which of the following pairs of entities is most likely to be modeled as a M:M relationship? -TREE and BRANCH -PERSON and FINGERPRINT -TEACHER and SUBJECT AREA -CAR and WHEEL

-TEACHER and SUBJECT AREA

Which of the following are examples of ENTITY: Instance ? (Choose Two) (Choose all correct answers) -MEAT PRODUCT: Lettuce -TRANSPORTATION METHOD: Car -BODY PART: Larry Ellison -ANIMAL: Dog

-TRANSPORTATION METHOD: Car -ANIMAL: Dog