CS 148 Final
What is the primary key of the PhoneNumber table? Table has no primary key (AreaCode, Number) (AreaCode, Exchange, Number)
(AreaCode, Exchange, Number)
Which column is a foreign key in the new table? FlightNumber only PassengerNumber only (FlightNumber, PassengerNumber)
(FlightNumber, PassengerNumber) (FlightNumber, PassengerNumber) is the primary key of the initial table containing ChangeTimestamp. When a plural attribute becomes a new dependent table, the primary key of the initial table becomes a foreign key.
What is the primary key of the new table? (FlightNumber, PassengerNumber) (FlightNumber, PassengerNumber, ChangeTimestamp) ChangeTimestamp
(FlightNumber, PassengerNumber, ChangeTimestamp) All three columns of the new table are necessary for uniqueness and must be included in the composite primary key of the new table.
In the HealthPlan table, which foreign key value is fully NULL? (6381, NULL) (NULL, NULL) No foreign key values are fully NULL
(NULL, NULL) is fully NULL, since all foreign key columns are NULL.
What is the primary key of the new table? CreditCardNumber (PassengerNumber, CreditCardNumber) The composite of PassengerNumber, CreditCardNumber, and a third column of the new table.
(PassengerNumber, CreditCardNumber)
Which entity does EmploymentStatus belong to? Person Student Faculty Administrator
Administrator
In a join, what are the first and second tables in the FROM clause called? Left and right tables, respectively. Right and left tables, respectively. Table one and table two, respectively.
Left and right tables, respectively.
What is value E?
MATH, The view contains professors in the Math Department only, so the view query must restrict department code to MATH.
What is table name A?
MathFacultyView,The name of the view table immediately follows the CREATE VIEW keywords.
Primary key
Maximum and minimum cardinality of one.
unique
Maximum cardinality of one.
NOT NULL
Minimum cardinality of one.
no keyword
Minimum cardinality of zero. Minimum cardinality of zero indicates NULL values are allowed. NULL values are allowed in columns when no keyword is specified.
Are NULLs allowed in the foreign key column? Yes No
NO, The foreign key column must be NOT NULL, since each Contact is related to at least one Passenger.
Can (ID, Relationship) be the primary key of Family? Yes No Cannot determine answer from data in the table.
NO, (ID, Relationship) cannot be the primary key because (6381, Daughter) is repeated. Composite primary keys must be unique.
What is the result of 0 < NULL in MySQL? NULL UNKNOWN 0
NULL
CHAR
Nadia
What is included in a glossary? Descriptions only Names and synonyms only Names, synonyms, and descriptions only Names, synonyms, descriptions, and ER diagrams
Names, synonyms, and descriptions only
Does the NULL in the Manager column violate referential integrity? Yes No
No
Which department has the same manager and assistant? Engineering Sales No department has the same manager and assistant.
No department has the same manager and assistant.
CREATE TABLE Student ( StudentNumber MEDIUMINT, CollegeName VARCHAR(20) ______, EmailAddress VARCHAR(30) )
Not null
How many dependency relationships can each dependent entity have? Zero or one Exactly one One or many
One or many
Which columns can be compared in a join? Only primary and foreign key columns. Only columns with comparable data types. Any columns.
Only columns with comparable data types.
What is the result of a relational operation?
a table
insert a foreign key
add human resources to the department table with manager 1420
Discovery is a step in which phase? Analysis Logical design Database design
analysis
The duration of a project becomes a(n) ________.
attribute, An attribute is a property of an entity. Since "duration of a project" describes project, duration is an attribute.
The starting date of a task becomes a(n) ________.
attribute, An attribute is a property of an entity. Since "starting date of a task" describes task, "starting date" is an attribute.
The foreign key in the subtype table usually has the referential integrity action ________ on primary key delete.
cascade
update foreign key
change the technical support department manager to 8001
update pmk
changing ID
What is view column name D?
code, The view query joins Faculty to Department on the Code columns of both tables.
Identify partitions and partition attributes.
create supertype and subtype entities Partitions are groups of mutually exclusive subtype entities.
In some diagrams, 'many' is depicted with ______ notation.
crows feet
Exam-BelongsTo-Course
dependency relationship "BelongsTo" is the relationship which reflects the dependence of Exam on Course.
exam
dependent entity According to the requirements, an exam instance exists only in relation to a course instance. The Exam entity depends on the Course entity.
Determine attribute maxima and minima.
determine cardinality Cardinality is a general term for maxima and minima.
List standard attribute types in glossary.
discover entities, relationships, and attributes Standard attribute types are used in naming attributes, which takes place during discovery.
Determine the dependency relationship for each dependent entity.
distinguish independent and dependent entities Dependency relationships relate dependent entities to a master entity.
In the relational data structure, which components are named?
domain, relation, attribute
All projects in the company become a(n) ________.
entity , An entity is a thing, such as a person, place, or activity. Since a project is a thing, project is an entity.
How many values may appear in each cell? Any number of values Exactly one value No values or one value
exactly one value
Maxima and minima usually depend on business rules. True False
true Although some maxima and minima are universal, most depend on business rules and are determined during interviews and document review.
VehicleIdentificationNumber is a good primary key. True False
true
Views can be used to hide rows as well as columns from database users. True False
true
BLOB
00011011001
DATE
09/12/1986
INT
16
FLOAT
3.14
Which choice is a cell value? ID Elsa Brinks 30500
30500
attribute instance
324A21, 324A21 is an individual student record number. Individual values are attribute instances.
In the Department table, which foreign key value violates referential integrity? 2538 3829 NULL
3829,Since no employee has ID 3829, 3829 violates referential integrity.
Are NULLs allowed in the foreign key column? Yes No Allowing NULL in the foreign key column depends on relationship minimum.
Allowing NULL in the foreign key column depends on relationship minimum. NULLs in the foreign key column depend on relationship minimum on the Aircraft side. If minimum is 0, NULLs are allowed. If minimum is 1, NULLs are not allowed.
What is the name of the new foreign key? FlightNumber AircraftCode AssignedAircraftCode
AssignedAircraftCode
What is designated family member name? Subtype entity Attribute of Passenger Attribute of GoldPlanMember
Attribute of GoldPlanMember
What is mileage plan number? Subtype entity Attribute of Passenger Attribute of GoldPlanMember
Attribute of Passenger
In the HealthPlan table, which foreign key value violates referential integrity? (NULL, NULL) only (6381, NULL) only (6381, 4) only Both (6381, NULL) and (6381, 4)
Both (6381, NULL) and (6381, 4)
An entity-relationship model is completely described by: An ER diagram A glossary Both an ER diagram and a glossary
Both an ER diagram and a glossary
How can driver's license information be added to the Employee table? Driver's licenses cannot be added, since the Employee table already has an ID column. By creating another column named ID. By creating another column with a new name, such as ID2 or DriverLicense.
By creating another column with a new name, such as ID2 or DriverLicense.
What are keywords D? 5.7 zy books
CHECK OPTION, WITH CHECK OPTION are optional keywords at the end of a CREATE VIEW statement. WITH CHECK OPTION prevents inserts and updates that violate the WHERE clause.
cross join
Combines two tables without comparing columns.
equijoin
Compares columns of two tables with the = operator.
non-equijoin
Compares columns with an operator other than =, such as < and >.
first or second normal form
Consider denormalizing tables in reporting databases. Denormalization intentionally introduces redundancy, resulting in first- or second-normal-form tables.
Which database is relational?
DB2
Which column must be removed to achieve third normal form? DepartmentCode CourseName DepartmentChairName
DepartmentChairName DepartmentChairName depends on the non-key column DepartmentCode and must be removed to achieve third normal form.
Which dependency violates third normal form? CourseName depends on DepartmentCode DepartmentChairName depends on DepartmentCode DepartmentChairName depends on CourseCode
DepartmentChairName depends on DepartmentCode Each department has one chair, so DepartmentChairName depends on DepartmentCode. Since DepartmentCode is a non-key column, this dependency violates third normal form.
What is column name C?
DepartmentName, The Assignment column of the view table contains DepartmentName values, so the SELECT clause must specify 'DepartmentName AS Assignment'
Several foreign keys can refer to the same primary key.
DepartmentStaff table
If DepartmentView is a materialized view, against what tables is the query executed? SELECT * FROM DepartmentView; Department only Faculty and Department DepartmentView
DepartmentView A materialized view is stored by the database, so the user query executes against the materialized view instead of the base tables.
What is missing to get all Chair names? SELECT Chair FROM ______;
DepartmentView contains the columns DepartmentName and Chair.
What is wrong with the following entity description? The difference between a course and a class is that a course refers to the catalog description, while a class is an individual offering of a class in a specific term. Description does not begin with entity name. Description does not include counterexamples. Description does not use complete sentences.
Description does not begin with entity name.
What is wrong with the following relationship description? "Student-Takes-Course" describes all course instances taken by a student instance. Description should begin with entity name. Description does not include examples and counterexamples. Description does not use complete sentences.
Description does not include examples and counterexamples.
relationship instance
Eleanor Rigby takes the final exam in calculus, "Eleanor Rigby" is a student entity instance. "Final exam in calculus" is an exam entity instance. A statement about entity instances is a relationship instance.
entity instance
Eleanor Rigby, a student at San Antonio community college, In some sentences, "Eleanor Rigby" might refer to a value of the name attribute, or attribute instance. However, in the sentence "Eleanor Rigby, a student at San Antonio community college", the name refers to a student, which is an entity instance.
second normal form
Eliminate dependencies on columns contained within a composite unique column. In second-normal-form tables, non-key columns depend on the whole key.
boyce- codd normal from
Eliminate dependencies on non-unique columns. In Boyce-Codd-normal-form tables, all dependencies are on unique columns. Non-unique columns are either external to all unique columns or contained within a composite unique column. To achieve Boyce-Codd normal form, dependencies are eliminated on both types of non-unique columns.
What non-key column must be removed to achieve second normal form? ScoreNumber GradeLetter EmailAddress
EmailAddress depends on StudentNumber, which is part of the primary key. EmailAddress must be moved to another table to achieve second normal form.
Foreign keys may refer to a primary key in the same table.
EmployeeManager table
Redundancy is the repetition of a value. True False
FALSE
What is the result of FALSE AND NULL in SQL Server? TRUE FALSE NULL
FALSE
If the view table is not stored, against what tables is the query executed? SELECT * FROM DepartmentView; Department only Faculty and Department DepartmentView
Faculty and Department, Because the view table is not stored, the user query and view query are merged into a single query against the two base tables.
What are the view query's base tables? Faculty only Faculty and Department DepartmentView
Faculty and Department,The base tables are specified in the view query's FROM clause.
LEFT
Faculty is the left table and Department is the right table. The left join includes all rows from Faculty. Grey has no department, so NULL appears for the department name.
RIGHT
Faculty is the left table and Department is the right table. The right join includes two departments that do not match any faculty rows. When a department has no faculty, NULL appears for the faculty name. Correct
Name is a good primary key.
False
T/F:The CHAR data type represents a variable string of characters.
False
The logical design phase ends when attributes have been implemented as columns. True False
False
Foreign keys may be composite.
HealthPlan table
What is the name of the new table? PassengerCreditCard Ownership PassengerCreditCardOwnership
PassengerCreditCard The name of a table implementing a many-many relationship usually consists of the names of the related entities. If needed for clarity, the relationship name may be inserted between the entity names.
What is the name of the new foreign key? Passenger ContactNumber PassengerNumber
PassengerNumber Usually, foreign keys have the same name as the referenced primary key. Since the foreign key is placed in Contact and refers to Passenger, the foreign key name should be PassengerNumber.
What is (are) the foreign key(s) in the new table? The new table contains no foreign keys. PassengerNumber PassengerNumber and CreditCardNumber
PassengerNumber and CreditCardNumber
Which entity does TelephoneNumber belong to? Person Student Faculty Administrator
Person TelephoneNumber describes all people and should be assigned to the supertype Person.
What is column name B?
Professor, 'FacultyName AS Professor' in the view query indicates that 'Professor' replaces 'FacultyName' in the view table.
A table with a simple primary key must be in what normal form? First normal form only, and no higher Second normal form or higher Third normal form
Second normal form or higher
entity type
Students at San Antonio Community College, "Students" are a set of people. A set of things is an entity type..
What is gold plan member? Supertype entity Subtype entity Attribute
Subtype entity
Some of our passengers enroll in mileage plans and get a mileage plan number. Travelers who fly 100,000 miles or more in a calendar year are gold mileage plan members. Between 25,000 miles and 100,000 miles is silver status, and below 25,000 miles flown is bronze status. Gold members designate a family member who can fly for free. What is passenger? Supertype entity Subtype entity Dependent entity
Supertype entity
Tables that allow redundancy might contain inconsistent versions of the same fact. True False
TRUE
Third normal form allows fewer types of redundancy than second normal form. True False
TRUE, Higher-numbered normal forms are successively more restrictive, allowing fewer types of redundancy than lower-numbered normal forms.
SET NULL, when Lisa Ellison's ID is changed to 1001. The Engineering manager is set to NULL. The Engineering manager is set to 1001. The change is rejected.
The Engineering manager is set to NULL.
SET DEFAULT, when Lisa Ellison's ID is changed to 1001. The Engineering manager is set to NULL. The Engineering manager is set to a default value, such as 9999. The change is rejected.
The Engineering manager is set to a default value, such as 9999. SET DEFAULT sets matching foreign keys to a default value. Since Lisa Ellison manages Engineering, the Engineering manager is set to a default value, which must be a valid primary key in the Employee table.
CASCADE, when Maria Rodriguez is deleted. The Sales and Marketing managers are set to NULL. The Sales and Marketing departments are deleted. The delete is rejected.
The Sales and Marketing departments are deleted. CASCADE propagates primary key deletes to matching foreign keys. Maria Rodriguez manages Sales and Marketing, so the Sales and Marketing rows are deleted.
CASCADE, when Maria Rodriguez' ID is changed to 2022. The Sales and Marketing managers are set to NULL. The Sales and Marketing managers are set to 2022. The change is rejected.
The Sales and Marketing managers are set to 2022. CASCADE propagates primary key changes to matching foreign keys. Maria Rodriguez manages Sales and Marketing, so Sales and Marketing managers are set to 2022.
If the Department column is designated NOT NULL, what happens when a user attempts to insert a new employee without a department value? The database accepts the insert and stores a blank string as the Department name. The database accepts the insert and saves NULL in the column. The database rejects the insert.
The database rejects the insert.
RESTRICT, when the row containing Maria Rodriguez is deleted. The Sales and Marketing managers are set to NULL. The Sales and Marketing departments are deleted. The delete is rejected.
The delete is rejected.
FULL
The full join includes rows from the left and right tables that do not have matching department codes.
INNER
The inner join only includes rows where both tables share the same department code.
What does the principle of data independence state? The performance of a query is not related to the physical organization of data. Data in each row is independent of data in all other rows. The result of a database query is not affected by the physical organization of data on storage devices.
The result of a database query is not affected by the physical organization of data on storage devices.
The relational model was originally developed for which types of applications?
Transactional applications like banking and airline reservations
Plural attributes are implemented as new dependent tables. True False
True
______ is a modeling standard intended for software development
UML/ unified modeling language
What is the result of FALSE OR NULL in Oracle?
UNKOWN
How many dependent entities can depend on one independent entity? Zero or one One or many Zero, one, or many
Zero, one, or many
What is missing from the join statement? SELECT EmployeeName, Salary FROM Employee, Department WHERE Salary > 50000
a column from employee is not compared to a column from department
After the 'implement entities' step is completed, table and column specifications are final. True False
false
All design decisions in the 'implement entities' step are affected by the database system. True False
false
An entity instance can be in two subtypes of the same partition. True False
false
An entity-relationship model is developed for all database design projects. True False
false
Analysis considers details of a specific database. True False
false
Data type depends on attribute cardinality. True False
false
Data types are independent of the database system. True False
false
Denormalization accelerates all SELECT queries. True False
false
Denormalization never results in second-normal-form tables. True False
false
Determining cardinality always precedes distinguishing independent and dependent entities. True False
false
Distinguishing independent and dependent entities is a logical design activity. True False
false
Entities, relationships, and attributes always map directly to tables, foreign keys, and columns, respectively. True False
false
Foreign keys always have the same name as the referenced primary key. True False
false
In MySQL, two different queries that generate the same result table always have the same execution time. True False
false
Many-one and one-one relationships are always implemented before many-many relationships. True False
false
NULL in the Manager column refers to a row of the Employee table with a NULL ID. True False
false
One partition attribute can correspond to several partitions. True False
false
T/F:Delete cascade is an example of a structural rule.
false
The NULL in the Manager column may be replaced with 9876. True False
false
The activities of the 'implement entities' step are always executed in sequential order. True False
false
The composite (ManufacturerName, MakeCode, YearNumber) is a good primary key. True False
false
Using materialized views always improves database performance. True False
false
Values in a foreign key must be unique. True False
false
'Cardinality' refers to relationships only. True False
false Cardinality is a general term for minima and maxima of both relationships and attributes.
In the analysis phase, cardinality is always determined after discovery is complete. True False
false, In principle, discovery precedes determination of cardinality. However, analysis is an iterative process. In practice, cardinality is determined in parallel with discovery, and additional discovery takes place after cardinality is determined.
LicensePlateNumber is a good primary key. True False
false, LicensePlateNumber is unique and required but potentially unstable. When license plates are lost or stolen, the state may issue a new license plate number for the vehicle. Unstable attributes do not make good primary keys.
In ER diagrams, maxima and minima are drawn for relationships only. True False
false, Minima and maxima for both attributes and relationships can appear in ER diagrams.
DealerInvoiceNumber is a good primary key. True False
false, The (0) to the right of DealerInvoiceNumber indicates DealerInvoiceNumber is optional. Optional attributes result in NULL-valued columns, which cannot be primary keys.
"License" is a correct attribute name. True False
false, Attribute names must have a type suffix. The correct attribute name is "LicenseNumber", "LicenseCode", or similar. Optionally, the name can have an entity prefix, as in "EmployeeLicenseNumber".
All columns depend only on unique columns. True False
false, In the United States, each postal code is in exactly one state. Therefore, DriversLicenseState depends on PostalCode, which is not unique.
"Column B depends on column A" means each value of B relates to at most one value of A. True False
false, "Column B depends on column A" means each value of A relates to at most one value of B. Ex: If PassengerNumber is the primary key and PassengerName is a non-key column, PassengerName depends on PassengerNumber.
EmployeeID is the only candidate key. True False
false, (DriversLicenseNumber, DriversLicenseState) is unique and minimal, and therefore also a candidate key.
Database designers should ensure all tables are in fifth normal form. True False
false, As a practical matter, third normal form eliminates common types of redundancies. Usually, database designers are not concerned with higher normal forms.
First-normal-form tables have no dependencies between columns. True False
false, In a first-normal-form table, all non-key columns depend on the primary key. All tables are in first normal form.
Employee is in Boyce-Codd normal form. True False
false, Since one column depends on a column that is not unique, Employee is not in Boyce-Codd normal form. Consequently, Employee contains redundancy - the fact (CA, 90295) is repeated. The redundancy is eliminated by removing DriversLicenseState from Employee and creating a new table containing PostalCode and DriversLicenseNumber. The resulting tables are in Boyce-Codd normal form.
A new employee can be added with ID 5384. True False
false, already in table
"People" is a correct entity name. True False
false, plural
"Students" is a correct entity name. True False
false, should singular not plural
"Department-IsManagedBy-Employee" is a correct relationship name. True False
false, shouldn't be "ismanagedby"
A new employee can be added without an ID value. True False
false..its a primary key
The primary key of a subtype table is also a ________.
foreign key
In the Bonus column of the Lisa Ellison row, what does the zero represent?
has no bonus
Where are duplicate column names allowed? Within a single table. In different tables. Never.
in different tables
AcademicDepartment
independent entity According to the requirements, exams must belong to a course, and courses must belong to a department. Only academic departments exist without reference to another entity. AcademicDepartment is the only independent entity.
The foreign key in a subtype table implements the ________ relationship between subtype and supertype entities.
isa or dependency
self join
joins a table to itself
Person-Owns-Vehicle one-one one-many many-one many-many
many-many
Student-Takes-Course one-one one-many many-one many-many
many-many
Entity Employee, attribute LanguageCode one-one one-many many-many
many-many An employee may speak many languages, and each language may be spoken by many employees. Employee-Has-LanguageCode is many-many.
Entity Booking, attribute TotalCost one-one many-one many-many
many-one Each booking has one cost, and each cost can describe many bookings, so Booking-Has-TotalCost is many-one.
Entity Passenger, attribute PassengerName one-one one-many many-one
many-one Each passenger has one name, and each name can describe many passengers, so Passenger-Has-PassengerName is many-one.
Person-Has-MailingAddress one-one one-many many-one many-many
many-one, Several people can share the same mailing address. Assuming the business requires exactly one official mailing address for each person, Person-Has-MailingAddress is many-one.
Course and AcademicDepartment
master entity Exam depends on Course, so Course is the master entity for Exam. Course depends on AcademicDepartment, so AcademicDepartment is the master entity for Course.
_______ columns contain no descriptive information and make good primary keys.
meaningless
What are the components of a column? Name only Data type only Name and data type
name and data type
Must a table have at least one row? Yes No
no
Must entity, relationship, and attribute synonyms follow naming conventions? Yes Only attribute synonyms must follow naming conventions. No
no
How often do column names and data types change? Never Occasionally Often
occasionally
Person-Has-Passport one-one one-many many-one many-many
one - many
City-IsCapitalOf-State one-one one-many many-one many-many
one-one
Entity Airport, attribute AirportCode one-one one-many many-one
one-one Each airport has at most one airport code, and each airport code describes at most one airport. Airport-Has-AirportCode is one-one.
Flight-ArrivesAt-Airport zero-zero zero-one one-zero one-one
one-one, All flights must arrive at an airport. Assuming the database does not track new or inactive airports, all airports have arriving flights. Flight-ArrivesAt-Airport is one-one.
Person-Has-Passport zero-zero zero-one one-zero one-one
one-zero Every passport must belong to a person, but not all people have a passport. Person-Has-Passport is one-zero.
Sometimes students do not provide a telephone number on registration forms, so this information is left blank in the database.TelephoneNumber is a(n) _______ attribute of Student.
optional, The phrase "information is left blank in the database" indicates an optional attribute.
students can major in several subjects.MajorSubjectName is a(n) _______ attribute of Student.
plural, The word "several" indicates a plural attribute.
CREATE TABLE Student ( StudentNumber MEDIUMINT ______, CollegeName VARCHAR(20), EmailAddress VARCHAR(30) )
pmk
What was the initial impediment to commercial adoption of relational databases in the early 1980s?
processing speed
Our department tracks student information. We have a record of every course taken by students and the professor who taught the course. We also keep track of the name and number of credits for each course. For professors, we always store the name and current title, such as "Assistant Professor" or "Visiting Lecturer". Which noun is an entity? information name professor
professor "Professor" is a set of people. Since the database tracks professor names and courses taught, "Professor" is an entity.
"Task belongs to project" becomes a(n) ________.
relationship, A relationship is a statement about two things. Since "task belongs to project" is a statement about tasks and projects, the statement is a relationship.
delete a primary key
remove lisa from table
A ______ attribute becomes a column that is never NULL.
required
All students must have an official email address.EmailAddress is a(n) _______ attribute of Student.
required, The phrase "must have" indicates a required attribute.
Which terms are commonly used in relational database processing?
row, table, column
Which choice is a column name? 6381 Sam Snead Salary
salary
Name three operations of the relational algebra.
selection, projection, and union
The primary key of a table that implements a many-many relationship is composite. True False
true
A ______ primary key is easy to specify in a WHERE clause.
simple
We track at most one contact telephone number for each student.TelephoneNumber is a(n) _______ attribute of Student.
singular, The phrase "at most one" indicates a singular attribute.
How often is a master entity also an independent entity? Never Sometimes Always
sometimes
How does a database administrator specify column names and data types? In a special file managed by the database administrator With the Python language With the SQL language
sql
A _______ primary key reduces cascading updates in the database.
stable
We track the grade point average and telephone number for all students. We also track the phone number for faculty and administrative staff. Faculty have an academic ranking, like "Assistant Professor" or "Adjunct Professor". Administrative staff are either hourly or salaried, which we call employment status. Which entity does GradePointAverage belong to? Person Student Faculty Administrator
student
attribute type
student record number, "Student record number" is a set of numbers describing the student entity. A set of descriptive properties is an attribute type.
relationship type
student takes exams, "Students take exams" is a statement about student and exam, two entity types. A statement about entity types is a relationship type.
A group of related entities is often called a/an ______ .
subject area
The subtype table primary key is identical to the _______ table primary key.
supertype
Which verb is a relationship? taken track have
taken
Which noun is an attribute? record Assistant Professor title course
title, "Title" is a property that describes the professor entity, and is therefore an attribute.
"Employee-Manages-Employee" is a correct relationship name. True False
true
A binary data type stores data as an exact copy of computer memory. True False
true
A view query can reference another view table. True False
true
An attribute name indicates the data type of the corresponding column.
true
An entity instance can be in two subtypes of different partitions. True False
true
Attribute names always include an attribute type. True False
true
Database designers can look for dependency relationships first, before identifying dependent entities. True False
true
Each partition attribute value corresponds to one subtype. True False
true
No alternate keys are present. True False
true
Non-key columns always depend on the primary key. True False
true
Occasionally, database design skips a formal analysis phase and begins with logical design. True False
true
Occasionally, tables are denormalized in a frequently updated database. True False
true
Replacing NULL in the Manager column with 5384 assigns Sam Snead as the manager to the technical support department. True False
true
Sam Snead does not manage a department. True False
true
Some time data types include time zone. True False
true
T/F:Data in a relational database can violate relational rules.
true
T/F:Integrity rules and relational rules are synonymous.
true
T/F:Unique primary key is an example of a structural rule.
true
The data type of Manager and ID must be the same.
true
The performance of a user query on a view is identical to the performance of the corresponding merged query on base tables. True False
true
A new artificial key is a good primary key. True False
true An artificial key, such as VehicleNumber, is unique, required, stable, simple, and meaningless, and is a good primary key. However, VehicleIdentificationNumber is also a good primary key, although somewhat complex. Unless a simple primary key is important to database users, a new artificial key is unnecessary.
All non-key columns depend only on unique columns. True False
true, 'Non-key' means 'not contained in a candidate key'. The non-key columns are Name and PostalCode. Name and PostalCode depend only on EmployeeID and (DriversLicenseNumber, DriversLicenseState), which are unique.
Employee is in third normal form. True False
true, Since all non-key columns depend only on unique columns, Employee satisfies the definition of third normal form.
"PassengerMileagePlanCode" is a correct attribute name. True False
true, defined as mix of numbers and letters
CREATE TABLE Student ( StudentNumber MEDIUMINT, CollegeName VARCHAR(20), EmailAddress VARCHAR(30) ______ )
unique
Students are assigned an eight-digit number, used to identify students on forms and records.StudentNumber is a(n) _______ attribute of Student.
unique, The phrase "used to identify" indicates a unique attribute.
What does a NULL in the Name column represent? Unknown Inapplicable Either unknown or inapplicable
unknown
Idenfication of entities, relationships, and attributes precedes documentation. Always Usually Never
usually
Standard attribute types are determined after the ER diagram is drawn. Always Usually Never
usually
In some models, dependent entities are called ______ entities.
weak
Y/N:Are these relations the same? { (8, mango, FALSE), (-11, watermelon, FALSE) }{ (-11, watermelon, FALSE), (8, mango, FALSE) }
yes
Person-Marries-Person zero-zero zero-one one-zero one-one
zero-zero, Since a person can be unmarried, Person-Marries-Person is zero-zero.