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Questions and Answers of Databases

Draw the ER diagram for the two instance diagrams depicted here.
Adams, Ives, and Scott Incorporated is an agency that specializes in representing clients in the fields of sports and entertainment. Given the nature of the business, some employees are given a
Suppose you want to show that a person can have multiple degrees. Would each of the following two ER diagrams get the job done? Why or why not? What is the difference?
This vignette is a small excerpt from a comprehensive case about a clinic. Various physicians and surgeons working for a clinic are on an annual salary [o]. These doctors are identified by their
What is the difference between a stored attribute and a derived attribute?
Distinguish between a simple attribute, a single-valued attribute, a composite attribute, a multi-valued attribute, and a complex attribute. Develop an example similar to Figure 2.3 that illustrates
What is a unique identifier of an entity type? Is it possible for there to be more than one unique identifier for an entity type?
Consider the EMPLOYEE entity type given below.a. List all key and non-key attributes.b. What is (are) the unique identifier(s)?c. Which attribute(s) is (are) derived attributes?d. Using the figure in
What is information preservation and why is it important?
What four deletion rules are applicable to deletion constraints? Which rule(s) refer to an action on the parent and which rule(s) refer to an action on the child?
What must be done to develop a Design-Specific ER model from a Presentation Layer ER model?
When used in the context of data modeling, what is meant by the term "mapping"?
Which constructs in a Presentation-Layer ER diagram cannot be directly mapped to a logical schema? What is required to represent these constructs in a Design-Specific ER diagram?
Assume that data are maintained on airports around the country for a company that offers a flight chartering service for college basketball teams. They gather information from a wide variety of
Transform the look-across notation of the Presentation Layer ER diagram in Exercise 7 to a Design-Specific ER diagram that makes use of the (min, max) notation for specifying the structural
The NCAA (National Collegiate Athletic Association) wants to develop a database to keep track of information about college basketball. Each university team belongs to only one conference (e.g., the
This exercise contains additional information in the form of deletion rules that will enable us to develop a Design-Specific ER diagram for the NCAA database in Exercise 18. a. Incorporate the above
Describe what constitutes an ER Model.
Crow's Foot notation and IDEF1X notation are two other popular notations for the ER modeling grammar. Investigate these two types of grammar and compare them with the Chen's notation used in this
Examine the CASE tools, ERWin, and Oracle/Designer, and discuss the ER modeling grammar supported by each of them.
Give examples of types of business rules that are not reflected in a Presentation Layer ER diagram.
Consider the Presentation Layer ER diagram.a. Identify the base and weak entity types. What is (are) the unique identifier(s) of each entity type? Which unique identifiers are composite attributes?b.
What is the difference between an exclusive arc and an inclusive arc?
What is a deletion constraint?
What is the difference between an inter-entity class relationship and an intra-entity class relationship?
In categorization, what is meant by the property of selective type inheritance?
Explain how a total category and specialization are mutually substitutable constructs.
Contrast categorization and aggregation.
Consider the following Presentation Layer ER diagram.a. Identify all entity types that at one time or another function as a superclass.b. List the superclass entity type and subclass entity type(s)
Revise Figure 4.10 to allow (i.e., require) each individual to be a donor. Show how your revision allows the categorization construct to be replaced by the specialization/generalization construct.
This exercise is based on the three Presentation Layer ER diagrams that follow.a. Describe what is reflected by the entity types and relationship types in Presentation Layer ER diagram number 1. In
Consider the Presentation Layer ER diagram that appears in Figure 4.21.a. What makes SCHOOL part of the specialization lattice involving SCHOOL, NOT_FOR_PROFIT_ORGANIZATION, and PUBLIC_SCHOOL, and,
Develop valid deletion rules and incorporate the associated deletion constraints for the EERD in diagram 3 of Exercise 15. Then explain the meaning of the incorporated deletion constraints,
What is a subclass and when is a subclass of use in data modeling?
Under what circumstances in a specialization is it possible for both one superclass to be related to more than one subclasses and one subclass to be related to one or more superclasses?
What is the difference between specialization and generalization? Why is this difference not reflected in ER diagrams?
What is the difference between total specialization and partial specialization and how is each reflected in an ER diagram?
What is the difference between a specialization hierarchy and a specialization lattice?
What is a cluster entity type?
Convert the ERD in Figure 5.22 to the final form of Design-Specific ERD.
Transform the Design-Specific ERD in Figure 5.28 to a final-form Design-Specific ERD.
The weak relationship type shown in Figure 5.32 requires further decomposition preparatory to mapping to a logical schema. Develop the final form of the Design-Specific ERD.
What is a weak relationship type? Contrast a condition-precedent weak relationship type with an event-precedent weak relationship type.
What is a composite relationship type?
What is required in order to decompose a ternary and higher-order relationship type in preparation for mapping to a logical schema? What is the cardinality ratio of each of the resulting set of
What is required to decompose a cluster entity type in preparation for mapping to a logical schema?
Consider the ER diagram of Figure 5.5. State meaningful semantics for additional binary relationships among the entity types in the diagram and update the ER diagram accordingly with full
The Design-Specific ERD in Figure 5.13a requires further decomposition before it can be mapped to the logical tier. Specify the final form of the Design-Specific ERD that will render this design
Decompose the Design-Specific ERDs in Figures 5.17 and 5.18 to the final Design-Specific stage and explain the differences.
What is a relation schema? What is the difference between a relation, a relation schema, and a relational schema?
This exercise refers to the relations R1 and R2 given below. Show the relations created as a result of the following relational algebra operations
What would cause a relational schema for a database to contain more relation schemas than there are entity types?
Discuss the concept of information preservation in data model mapping.
What is required to map a base entity type to a relation schema? Describe how this approach differs for a weak entity type.
What is the purpose of the cross-referencing design?
What complicates the mapping of 1:1 cardinality ratios?
Describe mutual referencing and the complexities that it introduces.
What information is lost by the use of the information-reducing grammar?
Describe how to map a specialization hierarchy, a specialization lattice, and a categorization.
What do you think are the ultimate consequences of failure to "preserve information" in the data model mapping process?
Distinguish between a subset and a proper subset?
List (tabulate) the metadata available in the ER diagram in Exercise 23 on the next page and indicate the ones captured in the logical (relational) schema of design 23(a) and design 23(b)
Define the terms, tuple, attribute, and relation.
What is a null value? What gives rise to null values in a relation?
What is a candidate key? How does a candidate key differ from a superkey?
What is a primary key? How do the properties of a primary key differ from those of a candidate key?
Identify the superkeys, candidate key(s), and the primary key for the following relation instance of the STU-CLASS relation schema.
Define the term referential integrity constraint. Why is referential integrity important? How is the term foreign key used in the context of referential integrity?
Describe the two approaches used in this book to derive candidate keys.
What is the difference between (a) a prime attribute and a non-prime attribute and (b) a key and non-key attribute?
Consider the universal relation schema INVENTORY (Store#, Item, Vendor, Date, Cost, Units, Manager, Price, Sale, Size, Color, Location) and the constraint set F {fd1, fd2, fd3, fd4, fd5, fd6, fd7}
Given the set of functional dependencies F {fd1, fd2, fd3, fd4, fd5, fd6, fd7, fd8, fd9, fd10} where:a. Construct the universal relation schema that includes (i.e., preserves) the set of functional
Given the set of functional dependencies F {fd1, fd2, fd3, fd4, fd5, fd6, fd7, fd8, fd9, f10, f11} where:a. Construct the universal relation schema that includes (i.e., preserves) the set of
Given the Universal Relation Schema URS (A, B, C, D, F, G) and the set of FDs prevailing over URS F {fd1, fd2, fd3, fd4, fd5, fd6}, where:a. Derive a canonical cover of F.b. Derive all the candidate
Given the Universal Relation Schema URS (A, B, C, G, W, X, Y, Z) and the set of FDs prevailing over URS, F {fd1, fd2, fd3, fd4, fd5}, where:a. Derive a canonical cover of F.b. Derive the candidate
Explain why data redundancy exists for the attributes Discount and Location in the STOCK table in Figure 7.1c.
Explain functional dependency between two attributes.
Why can functional dependency not be inferred from a particular relation state?
Identify the set of functional dependencies in the relation instance CAR shown below. Does this constitute the minimal cover for the set of functional dependencies present in CAR? If it is not a
What is the difference between F, F+, and Fc?
What is the purpose of Armstrong's axioms?
Suppose F {fd1, fd2} consists of the following functional dependencies: fd1: Ssn → {Ename, Bdate, Address, Dnumber} fd2: Dnumber → {Dname, Dmgrssn} Which of Armstrong's axioms allows the
Why is it useful to know all the candidate keys of a relation schema?
Given a relation schema R (A, B, C) that is in 3NF: a. State the conditions under which modification anomalies can exist. b. Express the conditions stated above in terms of functional
What is the difference between 3NF and Boyce-Codd Normal Form (BCNF)?
Consider the relation schema PATIENT_VISIT (Patient, Hospital, Doctor) and the relation instance given below:In addition, suppose the following semantic rules exist.€¢ Each patient may be a
Why are attribute preservation, dependency preservation, and lossless-join decomposition requirements of a fully normalized database design?
Consider the relation schema ACTIVITY (Stu#, Sport, Cost) and associated relation instance shown below:a. What is the minimal cover of ACTIVITY? b. What, if any, immediate normal form violation
What is the difference between a loss-join decomposition and a lossless-join decomposition?
Consider relation SUPPLY (S#, Sname, P#, Qty) with supplier names unique such that:F: fd1: S# ïƒ Sname; fd2: Sname ïƒ S#; {S#, P#} ïƒ QtyS# represents a supplier number, Sname
Consider the relation schema CLASS with attributes Student, Subject, and Teacher. The meaning of this relation is that the specified student is taught the specified subject by the specified teacher.
This exercise is a variation of Exercise 18. Consider the following functional dependencies prevailing over the relation schema CLASS (Student, Subject, Teacher):{Student, Subject} †’
What is the difference between a desirable and an undesirable functional dependency? Describe the nature of the problems caused by undesirable functional dependencies. What prevents us from simply
Given the relation schema FLIGHT (Gate#, Flight#, Date, Airport, Aircraft, Pilot) and the constraint set F {fd1, fd2, fd3} where:fd1: {Airport, Flight#, Date}  Gatefd2: {Flight#, Date} 
Consider the universal relation schema INVENTORY (Store#, Item, Vendor, Date, Cost, Units, Manager, Price, Sale, Size, Color, Location) and the constraint set F {fd1, fd2, fd3, fd4, fd5, fd6, fd7}
Given the set of functional dependencies F {fd1, fd2, fd3, fd4, fd5, fd6, fd7, fd8, fd9, fd10} introduced originally in Chapter 7, Exercise 14:fd1: Tenant# ïƒ {Name, Job, Phone#, Address}
Figure 8.1 illustrates how a first normal form violation of ALBUM can be resolved. Suppose that a single album could never have more than four artists. Describe another approach for defining ALBUM
Suppose {A, B} → C in a relation schema R. Under what condition would this not reflect a full functional dependency?
Consider the relation instance of the STU-CLASS relation schema.Identify at least one update anomaly, one insertion anomaly, and one deletion anomaly.
Consider the following relation instance of the CAR relation schema:a. What is the minimal cover of functional dependencies that exists in CAR?b. What is (are) the candidate key(s) of CAR?c. If there

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