Oracle Study Guide Sections 1-10 – Flashcards
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What are the major content areas covered in the Oracle Academy? -SQL, database configuration, and performance tuning. -Data Modeling, PJava and C+ -Data Modeling, SQL, and PL/SQL -Database programming, and Computer repair.
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-Data Modeling, SQL, and PL/SQL
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The demand for Information Technology professionals in today's market is increasing. True or False? -True -False
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-True
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How do you turn "data" into "information"? -By testing it -By storing it in a database -By querying it or accessing it -By storing it on a server
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-By querying it or accessing it
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What are the results of having all your data in one central location? (Choose two) -Easier access to data -Improved performance -Updates are harder to execute -Decreased performance
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-Easier access to data -Improved performance
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Consider an example where an Oracle database works "behind the scenes" for common internet activity. Which of the following best describes a database transaction? -A person looks in the newspaper for good internet sites. -A student places a link to his homepage from the school's website. -A person searches an airline website to find all available fares for a flight. -A business identifies the processes it uses for purchasing inventory.
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-A person searches an airline website to find all available fares for a flight.
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Which of the following are examples of data vs. information: A.Student age vs. average age of all students in class B.Bank deposit amount vs. total account balance C.Winning time for a race vs. length of race D.Price of a computer vs. total sales of all computers for a company
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-A,B, and D
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Which of the following represents the correct sequence of steps in the Database Development Process? -Analyze, Design, Build -Build, Analyze, Design -Analyze, Build, Design -Design, Build, Analyze
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-Analyze, Design, Build
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Data Modeling is the last step in the database development process. True or False?
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-False (First Step)
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Oracle was one of the first relational database systems available commercially. True or False?
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-True
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The overall mission of the Oracle Corporation is to use the internet and fast processing servers to build its own network. True or False?
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-False
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Users would interact with which of the following software to access essential business applications? (Choose three) -Internet Browser software -GUI software -Server software -Operating System software
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-Internet Browser Software -GUI Software -Operating System Software
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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."
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-Yes
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Personal computers (PCs) have been in existence since 1950. True or False?
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-False
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In the grid computing model, resources are pooled together for efficiency. True or False?
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-True
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Which of the following are reasons we create conceptual models? -It facilitates discussion; a picture is worth a thousand words -It forms important ideal system documentation -It takes into account government regulations and laws -All of the above
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-All of the above
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An Entity Relationship Diagram is an example of a Physical Model. True or False?
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-False
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A customized hat sitting on your friend's head is an example of which model--the conceptual model or the physical model? -Physical Model -Conceptual Model
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-Physical Model
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Many reasons exist for creating a conceptual model. Choose three appropriate reasons from the options below. -They accurately describe what a physical model will contain. -They model functional and informational needs. -They capture current and future needs. -They model the information flow of data.
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-They accurately describe what a physical model will contain. -They model functional and informational needs. -They capture current and future needs.
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A/an _________ is a piece of information that in some way describes an entity. It is a property of the entity and it quantifies, qualifies, classifies, or specifies the entity. -Attribute -Process -Table -ERD
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-Attribute
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In a physical data model, an attribute is represented as a/an -Instance -Row -Column -Foreign Key
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-Column
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Entities are usually verbs. True or False?
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-False
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Which of the following entities most likely contains invalid attributes? -Entity: Mother. Attributes: Name, Birthdate, Occupation, Number of Children -Entity: Home. Attributes: Number of Bedrooms, Owner, Address, Date Built -Entity: Pet. Attributes: Name, Birthdate, Owner -Entity: Car. Attributes: Owner Occupation, Owner Salary, Speed
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-Entity: Car. Attributes: Owner Occupation, Owner Salary, Speed
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An entity may have which of the following? -Experiences -Instances -Tables -None of the above
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-Instances
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Which of the following statements about attributes are true? (Choose Two) -They have a data type, such as number or character string. -They describe, qualify, quantify, classify, or specify an entity. -They are often adjectives. -They must be single valued unless they belong to more than one entity.
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-They have a data type, such as number or character string. -They describe, qualify, quantify, classify, or specify an entity.
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In the following statements, find two good examples of ENTITY: Instance. (Choose Two) -DAIRY PRODUCT: milk -VEGETABLE: grows -BOOK: Biography of Mahatma Gandhi -TRAIN: runs
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-DAIRY PRODUCT: milk -BOOK: Biography of Mahatma Gandhi
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Unique Identifiers: -Distinguish all entities in a database -Distinguish nothing -Distinguish one instance of an entity from all other instances of that entity -Distinguish one entity from another
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-Distinguish one instance of an entity from all other instances of that entity
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The word "Volatile" means: -Static; unlikely to change -Changing constantly; unstable -Limited quantity -Large quantity
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-Changing constantly; unstable
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Some of the following could be attributes of an ENTITY called PERSON; select the INCORRECT attributes for PERSON. (Choose Two) -Priya Hansenna -Age -Freddy Wilson -Name
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-Priya Hansenna -Freddy Wilson
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All of the following would be instances of the entity PERSON except which? -Angelina Rosalie -David Jones -Grace Abinajam -Male
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-Male
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What is the purpose of a Unique Identifier? -Create an entity that is unlike any other entity aside from itself. -To identify a specific row within a table, using one or more columns and/or foreign keys. -To uniquely determine a table and columns within that table. -To identify one unique instance of an entity by using one or more attributes and/or relationships.
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-To identify one unique instance of an entity by using one or more attributes and/or relationships.
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An Entity Relationship model is independent of the hardware or software used for implementation. True or False? -True -False
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-True
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The purpose of an ERD is to document the proposed system and facilitate discussion and understanding of the requirements captured by the developer. True or False? -True -False
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-True
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A well structured ERD will show only some parts of the finished data model. You should never try to model the entire system in one diagram, no matter how small the diagram might be. True or False? -True -False
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-False
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Which of the following statements are true about ERD's? (Choose Two) -All data must be represented on the ERD, including derived summaries and the result of calculations. -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. -You should not model derivable data.
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-A piece of information should only be found in one place on an ERD. -You should not model derivable data.
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What are the three properties that every relationship should have? -A UID bar, a diamond, an arc -Transferability, degree, name -Name, optionality, arcs -Name, optionality, cardinality
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-Name, optionality, cardinality
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Relationships can be either mandatory or optional. True or False?
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-True
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Relationships always exist between -2 entities (or one entity and itself) -2 attributes -3 or more attributes -3 or more entities
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-2 entities (or one entity and itself)
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In a business that sells computers, choose the best relationship name from CUSTOMER to ITEM (computer, in this case). -Each CUSTOMER may be the producer of one or more ITEMS. -Each CUSTOMER must be the seller of one or more ITEMS. -Each CUSTOMER must be the buyer of one or more ITEMS. -Each CUSTOMER may be the maker of one or more ITEMS.
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-Each CUSTOMER must be the buyer of one or more ITEMS.
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Consider the recommended drawing conventions for ERD's. Indicate which of the following accurately describes diagramming conventions for entities and attributes: -The 'o' means that the attribute is optional; entity names should be plural verbs. -The '*' means that an attribute is mandatory or required; the entity name should be singular. -The 'o' means that the attribute is mandatory or required; the entity name should be a singular noun. -The '*' means that an attribute is optional; entity names should be plural verbs.
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-The * means that an attribute is mandatory or required; the entity name should be singular.
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Entity names are always plural. True or False?
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-False
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Which symbol is used to show that a particular attribute is optional? -# -& -* -o
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-o
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On an ER diagram, which symbol identifies an attribute as part of a unique identifier. -# -o -* -x
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-#
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Entity boxes are drawn as... -Soft Boxes -Normal Circles -Hard Boxes -Bold Circle
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-Soft Boxes
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Attributes are written inside the entity to which they belong. True or False?
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-True
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Two entities can have one or more relationships between them. True or False?
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-True
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After looking at the diagram, choose the sentence below that could be "read" from the existing relationship (even though you're missing relationship labels!) (Student)>-----------<(Activity) -Each Student may participate in one or more Activities. -Each Activity must belong to one and only one Student. -Each Activity may be performed by one or more Students. -Each Student must have one or more Activities.
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-Each Student may participate in one or more Activities.
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When reading a relationship between 2 entities, the relationship is only read from left to right. True or False?
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-False
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A Matrix Diagram will help you with all of the following except: -Verifying Relationships Between Entities -Defining Instances of Entities -Naming Relationships -Identifying Entities
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-Defining Instances of Entities
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Creating a Matrix Diagram is a mandatory step in Data Modeling. True or False?
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-False
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Matrix Diagrams help verify that you have identified all possible relationships between your existing entities. True or False?
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-True
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A subtype can have a relationship not shared by the supertype. True or False?
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-True
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Which of the following is the best scenario for using supertype/subtype entities: -A vehicle dealership that sells boats on trailers, cars, and trucks. -A pet store that sells small animals that need different sized cages and different food. -A grocery store that gives customers a choice of plastic or paper bags.
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-A vehicle dealership that sells boats on trailers, cars, and trucks.
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All instances of a subtype must be an instance of the supertype. True or False?
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-True
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All instances of the supertype are also instances of one of the subtypes. True or False?
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-False
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If subtypes are listed, a supertype should have at least two subtypes. True or False?
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-False
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Which of the following is a TRUE statement about the diagram below? ( B ) ( ) ((A)(Z) ) -Every Z is either an A or a B -Every B is a Z -Every A is a Z -Every A is a B
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-Every A is a B
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Which of the following is true about supertypes and subtypes? -Two subtypes from the same supertype have a one-to-one relationship between them -Subtypes inherit the relationships and attributes of the supertype. -Subtypes may have no more than 2 levels of nesting. -Supertype and subtype entities must mutually exclude one another
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-Subtypes inherit the relationships and attributes of the supertype.
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The "Other" subtype is best used: -For instances that belong to the supertype and at least one other subtype. -For a subtype that does not have any of the same attributes as the supertype to which it belongs. -As an extra subtype to ensure that the list of subtypes is exhaustive. By having an "Other" subtype, all instances of the Supertype will have a subtype to belong to. -You should never have a subtype called "Other".
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-As an extra subtype to ensure that the list of subtypes is exhaustive. By having an "Other" subtype, all instances of the Supertype will have a subtype to belong to.
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How should you handle constraints that cannot be modeled on an ER diagram? -List them on a separate document to be handled programmatically -Explain them to the users so they can enforce them -Always let the network architect handle them -All constraints must be modeled and shown on the ER diagram
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-List them on a separate document to be handled programmatically
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How would you model a business rule that states that on a student's birthday, he does not have to attend his classes? -Use a supertype -You cannot model this. You need to document it -Make the attribute Birthdate mandatory -Use a subtype
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-You cannot model this. You need to document it
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Which of the following is an example of a structural business rule? -All overdue payments will have an added 10 % late fee. -All products will have a selling price no less than 30 % greater than wholesale. -All employees must belong to at least one department. -Buildings to be purchased by the business must be current with earthquake building code.
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-All employees must belong to at least one department.
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'Only managers can approve travel requests' is an example of which of the following? -An optional business rule. -A mandatory business rule. -A structural business rule. -A procedural business rule.
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-A procedural business rule.
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A business rule such as "All accounts must be paid in full within 10 days of billing" is best enforced by: -Hiring a programmer to create additional programming code to identify and report accounts past due. -Making the relationship between CUSTOMER and PAYMENT fully mandatory and 1:1 on both sides. -Making the payment attribute mandatory. -Creating a message to be printed on every bill that reminds the customer to pay within ten days.
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-Hiring a programmer to create additional programming code to identify and report accounts past due.
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Business rules are important to data modelers because: -They capture all of the needs, processes, and required functionality of the business. -They are easily implemented in the ERD diagram. -The data modeler must focus on structural rules, because they are easily represented diagrammatically and eliminate other rules that involve extra procedures or programming. -Both A and C are true.
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A. They capture all of the needs, processes, and required functionality of the business.
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Why is it important to identify and document business rules? -It allows you to create your 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
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-It allows you to create your data model and then check it for accuracy.
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If a relationship can be moved between instances of the entities it connects, it is said to be: -Implicit -Committed -Recursive -Transferable
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-Transferable
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A non-transferable relationship is represented by which of the following symbols? -Diamond -Heart -Circle -Triangle
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-Diamond
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Non-transferable relationships can only be mandatory, not optional. True or False?
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-False
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Which of the following are relationship types? (Choose Two) -One to Another -Many to Many -One to Many -One to Some
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-Many to Many -One to Many
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What uncommon relationship is described by the statements: "Each LINE must consist of many POINTS and each POINT must be a part of many LINES" -One to Many Mandatory -Many to Many Mandatory -Many to Many Optional -One to Many Optional
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-Many to Many Mandatory
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When are relationships unnecessary? -When you can derive the relationship from other relationships in the model -When they have the same visual structure but different meaning -When the information does not relate to the model -When the relationships connect 2 entities and they each have distinct meanings
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-When you can derive the relationship from other relationships in the model
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If the same relationship is represented twice in an Entity Relationship Model, it is said to be: -Redundant -Removable -Replicated -Resourceful
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-Redundant
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Which of the following pairs of entities is most likely to be modeled as a M:M relationship? (Choose Two) -RENTAL CAR and DRIVER -TREE and SEEDLING -STUDENT and CLASS -PARENT and CHILD
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-RENTAL CAR and DRIVER -STUDENT and CLASS
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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.
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-Barring the relationships to the original entities.
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Many-to-Many relationships are perfectly acceptable in a finished ERD. There is no need to do any more work on them. True or False?
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-False
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When you resolve a M:M by creating an intersection entity, this new entity will always inherit: -A relationship to each entity from the original M:M. -The attributes of both related entities. -The UID's from the entities in the original M:M. -Nothing is inherited from the original entities and relationship.
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-A relationship to each entity from the original M:M
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Many to many relationships between entities usually hide what? -Uniqueness -Another relationship -More attributes -Another entity
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-Another entity
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When resolving a M:M relationship, the new relationships will always be __________ on the many side. -Optional -Mandatory -Redundant -Recursive
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-Mandatory
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A unique identifier can only be made up of one attribute. True or False?
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-False
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People are not born with "numbers", but a lot of systems assign student numbers, customer IDs, etc.?A shoe has a color, a size, a style, but may not have a descriptive "number". To be able to uniquely and efficiently identify one instance of the entity SHOE, a/an ______________ UID can be created. -Artificial -Structured -Unrealistic -Identification
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-Artificial
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An entity can only have one UID. True or False?
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-False
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A UID can be made up from the following: (Choose Two) -Entities -Synonyms -Relationships -Attributes
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-Relationships -Attributes
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When data is stored in more than one place in a database, the database violates the rules of ___________. -Normalization -Decency -Replication -Normalcy
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-Normalization
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When all attributes are single-valued, the database model is said to conform to: -3rd Normal Form -4th Normal Form -1st Normal Form -2nd Normal Form
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-1st Normal Form
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The following entity is in 1st normal form: True or False? ENTITY: VEHICLE ATTRIBUTES: REGISTRATION MAKE MODEL COLOR DRIVER PASSENGER 1 PASSENGER 2 PASSENGER 3
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-False
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An entity can have repeated values and still be in 1st Normal Form. True or False?
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-False
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What is the rule of Second Normal Form? -All non-UID attributes must be dependent upon the entire UID. -Some non-UID attributes can be dependent on the entire UID. -No non-UID attributes can be dependent on any part of the UID. -None of the above
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-All non-UID attributes must be dependent upon the entire UID.
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Examine the following entity and decide which attribute breaks the 2nd Normal Form rule: ENTITY: CLASS ATTRIBUTES: CLASS ID DURATION SUBJECT TEACHER NAME AND ADDRESS -DURATION -TEACHER NAME AND ADDRESS -SUBJECT -CLASS ID
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-TEACHER NAME AND ADDRESS
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An entity can be on 2nd Normal Form even if it has repeated values. True or False?
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-False
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No database in the world is ever truly on 3rd Normal Form. Everyone always stops after 2nd Normal Form. True or False?
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-False
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Examine the following Entity and decide which sets of attributes break the 3rd Normal Form rule: (choose two) ENTITY: TRAIN (SYNONYM: ROLLING STOCK) ATTRIBUTES: TRAIN ID MAKE MODEL DRIVER NAME DEPARTURE STATION NUMBER OF CARRIAGES NUMBER OF SEATS DATE OF MANUFACTURE -TRAIN ID, MAKE -MODEL, DATE OF MANUFACTURE -NUMBER OF CARRIAGES, NUMBER OF SEATS -DEPARTURE STATION, DRIVER NAME
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-NUMBER OF CARRIAGES, NUMBER OF SEATS -DEPARTURE STATION, DRIVER NAME
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As a database designer, you have a responsibility to store data in only one place and in the best possible place. True or False?
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-True
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To visually represent exclusivity between two or more relationships in an ERD you would most likely use a/an ________. -Arc -UID -Supertype -Subtype
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-Arc
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Which of the following would best be represented by an arc? -STUDENT (will-attend-university, will-not-attend-university) -STUDENT (graduating, non-graduating) -STUDENT (senior, junior) -STUDENT ( University, Trade School)
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-STUDENT ( University, Trade School)
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This diagram could also be expressed as a supertype/subtype construction. True or False? ( Student ) (COURSE ) ( #*ID ) (#*ID ) (* First Name) -----__l___l_--(oDifficulty ) (*Last Name ) (*Descripton) (oEye Color )
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-False
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All attributes that are part of the UID are mandatory. True or False?
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-True
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Which of the following can be added to a relationship? -An attribute -An arc can be assigned -A composite attribute -An optional attribute can be created
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-An arc can be assigned
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Secondary UID's are... -Mandatory in data modeling -Not permitted in data modeling -Always comprised of numbers -Useful as an alternative means of identifying instances of an entity
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-Useful as an alternative means of identifying instances of an entity
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If the entity CD has the attributes: #number, *title, *producer, *year, o store name, o store address, this entity is in 3rd Normal Form ("no non-UID attribute can be dependent on another non-UID attribute). True or False?
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-False
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Which of the following is the definition for Third Normal Form? -All attributes are single valued -All attributes are uniquely doubled and independent -No non-UID attribute can be dependent on another non-UID attribute -An attribute must be dependent upon the entity's entire UID
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-No non-UID attribute can be dependent on another non-UID attribute
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Which of the following would be a good Unique Identifier for its Entity? (Choose Two) -Identification Number for Person -Birthdate for Baby Which Includes Hour, Minute, and Second -Order date for Order -Vehicle Identification Number for Car
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-Vehicle Identification Number for Car -Identification Number for Person
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In this simple diagram, what comprises the unique identifier for the student class entity? ( Student ) (COURSE ) ( #*ID ) (#*ID ) (* First Name) -----__l___l_--(oDifficulty ) (*Last Name ) (*Descripton) (oEye Color ) -student id and class id -student id, class id, and course id -course id -student id and course id
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-student id and class id
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A relationship can be both recursive and hierarchical at the same time. True or False?
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-False
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A recursive relationship should not be part of a UID. True or False?
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-True
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Historical data should always be kept. True or False?
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-False
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Modeling historical data can produce a unique identifier that includes a date. True or False?
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-True
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Audit trail attributes cannot be placed in the entities they are auditing, they must be placed in separate, new entities, created just for that purpose. True or False?
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-False
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Which of the following scenarios should be modeled so that historical data is kept? (Choose two) -LIBRARY and NUMBER OF STAFF -STUDENT and AGE -STUDENT and GRADE -LIBRARY and BOOK
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-STUDENT and GRADE -LIBRARY and BOOK
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How do you know when to use the different types of time in your design? -It depends on the functional needs of the system . -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. -The rules are fixed and should be followed.
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-It depends on the functional needs of the system .
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In a payroll system, it is desirable to have an entity called DAY with a holiday attribute when you want to track special holidays. True or False?
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-True
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When you add the concept of time to your data model, you are: -Adding complexity to your model. -Just changing the model, but this does not change the complexity of it. -Simplifying your model. -None of the above.
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-Adding complexity to your model.
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What is the benefit to the users of a system that includes "time"; e.g. Start Date and End Date for Employees? -System becomes 100% unstable; allows users to log on and log off at will. -Increased usability and flexibility of a system; e.g., we can the trace the different managers an employee had over time. -Reporting becomes nearly impossible; users enjoy this. -Users are able to create complex programs in support of this component.
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-Increased usability and flexibility of a system; e.g., we can the trace the different managers an employee had over time.
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If you are tracking employment dates for an employee, do you need to have an "End Date" attribute? -Yes, because you always need an end date when you have a start date. -No, not if the company likes the employee. -Yes, if the company wants to track multiple start dates and insure that multiple employment dates for an employee do not overlap. -No, because an end date is usually redundant.
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-Yes, if the company wants to track multiple start dates and insure that multiple employment dates for an employee do not overlap.
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Which of the following would be a logical constraint when modeling time for a country entity? -Daily traffic patterns must be monitored to determine which countries are overcrowded. -Countries may change their names and/or borders over a period of time. -If you are doing a system for France or Germany, you would need security clearance. -People have births and deaths in their countries that must be tracked by the system.
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-Countries may change their names and/or borders over a period of time.
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Modeling historical data produces efficient ways for a business to operate such as: -Employees can work in two time zones. -Providing valuable information via reports to management . -Modeling historical data does not help a business. -Keeping track of holiday dates.
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-Providing valuable information via reports to management .
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Why would you want to model a time component when designing a system that lets people buy bars of gold? -The Government of your country might want to be notified of this transaction. -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. -Sales people must determine where the gold is coming from.
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-The price of gold fluctuates and, to determine the current price, you need to know the time of purchase.
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What is the function of logging or journaling in conceptual data models? -Gives a timestamp to all entities. -Allows you to track the history of attribute values, relationships, and/or entire entities -Creates a fixed time for all events in a data model. -Represents entities as time in the data model.
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-Allows you to track the history of attribute values, relationships, and/or entire entities
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Which of the following is a logical constraint that could result from considering how time impacts the storage of data? -End Date must be before the Start Date. -An ASSIGNMENT may only refer to a COUNTRY that is valid at the Start Date of the ASSIGNMENT. -Dates have value only with a time component. -ASSIGNMENT periods can overlap causing the database to crash.
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-An ASSIGNMENT may only refer to a COUNTRY that is valid at the Start Date of the ASSIGNMENT.
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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
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E. Both A and C
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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. The Layout is insignificant. True or False?
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-False
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In an ERD, it is a good idea to group your entities according to the expected volumes. By grouping high volume entities together, the diagrams could become easier to read. True or False?
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-True
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Which of the following statements are true to enhance the readability of ERDs? (Choose Two) -It does not matter which way the crows feet (many ends of a relationship) point. -Relationship lines should not cross. -Crossing relationship lines help the readability of the diagram. -Crows feet (the many-ends of relationships) should consistently point the same direction, either South & East or North & West
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-Crows feet (the many-ends of relationships) should consistently point the same direction, either South & East or North & West -Relationship lines should not cross.
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You must make sure all entities of a proposed system can fit onto one diagram. It is not allowed to break up a data model into more than one diagram. True or False?
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-False
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Generic models are generally less complex than a specific model. True or False?
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-False
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All data models MUST include generic components in order to remain flexible. True or False?
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-False
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When you transform a specific model to a generic model, which of the following statements are true? (Choose Two) -Either all or none of the original attributes make it into the generic model. -You will always have more entities in a generic model than in the corresponding specific model. -You tend to end up with fewer entities in the generic model than you had in the specific model. -None of the original specific model attributes are allowed in a generic model.
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-Either all or none of the original attributes make it into the generic model. -You tend to end up with fewer entities in the generic model than you had in the specific model.
