Database Management System Set 10

Database Management System

Questions 91 to 100

91.	A database management software (DBMS) includes (a) Automated tools (CASE) used to design databases and application programs (b) A software application that is used to define, create, maintain and provide controlled access to user databases (c) Application programs that are used to provide information to users (d) Database that contains occurrences of logically organised data or information (e) Repository of meta data, which is a central storehouse for all data definitions, data relationships,  screen and report formats and other system components.
92.	Making a change to the conceptual schema of a database but not affecting the existing external schemas is an example of (a) Physical data independence (b) Concurrency Control (c) Logical data independence (d) Functional dependency (e) Integrity Control.
93.	If K is a foreign key in a relation R1, then (a) Every tuple of R1 has a distinct value for K (b) K cannot have a null value for tuples in R1 (c) K is a key for some other relation (d) K is a Primary key for R1 (e) K is a Composite key for R1.
94.	Which of the following concept is applicable with respect to 2NF? (a) Full functional dependency (b) Partial dependency (c) Transitive dependency (d) Non-transitive dependency (e) Data independence.
95.	Consider the following relation: Attribute 1 Attribute 2 Attribute 3 Attribute 4 Attribute 5 A1 B2 C1 D4 E3 A3 B2 C3 D2 E4 A1 B3 C1 D1 E2 A2 B4 C1 D4 E5 What are the functional dependencies which apply to the above relation? (a) Attribute 1  à   Attribute 3 (b) Attribute 4  à   Attribute 5 (c) Attribute 3  à   Attribute 5 (d) Attribute 2  à   Attribute 1 (e) Attribute 4  à   Attribute 2.
96.	Embedded SQL means (a) Using the EMBED key word in a SQL statement (b) Writing a SQL statement to retrieve data from more than one relation (c) Writing SQL statements within codes written in a general programming language (d) Specifying a condition and action to be taken in case the given condition is satisfied in a trigger (e) Using SQL language constructs like revoke and grant respectively for revoking and granting privileges to users.
97.	“In 1978 committee proposed a generalized framework for database systems and it provides a three_level architecture. The of the architecture defines user views of the database. The defines the physical view of the database. The defines the logical schema of the database.” Which of the following set is suitable to fill the blanks in the above paragraph? (a) i.     ANSI/ARPANET ii.     Conceptual Level iii.    External Level iv.    Internal Level (b) i.     ANSI/SPARC ii.     Conceptual Level iii.    External Level iv.    Internal Level (c) i.     .ANSI/ARPANET ii.     External Level iii.    Internal Level iv.    Conceptual Level (d) i.     ANSI/SPARC ii.     External Level iii.    Internal Level iv.    Conceptual Level (e) i.     W3C ii.     Internal Level iii.    External Level iv.    Conceptual Level.
98.	Consider the following ER diagram depicting the relationship of an employee and supervisor: What is the possible relation if the above ERD is mapped into a relational model? (a) Employee (EmpID, BirthDate, Salary, Name(FirstName, MiddleName, LastName)) (b) Employee (EmpID, BirthDate, Salary, Name(FirstName, MiddleName, LastName)} (c) Supervision (EmpID, BirthDate, Salary, Name(FirstName, MiddleName, LastName), EmpID) (d) Supervisor (SupervisorID, BirthDate, Salary, Name(FirstName, MiddleName, LastName),EmpID), {EmpID}) (e) Employee (EmpID, BirthDate, Salary, Name(FirstName, MiddleName, LastName), SupervisorID).
99.	Select the correct statement from the following on proper naming of schema constructs: (a) Entity type name applies to all the entities belonging to that entity type and therefore a plural name is selected for entity type (b) In the narrative description of the database requirements, verbs tend to indicate the names of  relationship types (c) The nouns arising from a database requirement description can be considered as names of attributes (d) Additional nouns which are appearing in the narrative description of the database requirements represent the weak entity type names (e) Adjectives written in the database requirement description help to identify the partial relationships among entities.
100.	Consider the following table obtained using Student and Instructor relations. Fname Lname Ajith Gamage Sujith Hewage Kasun Peiris Which relational algebra operation could have been applied on the pair of relations Student and Instructor to obtain the above data? (a) Student ∩ Instructor (b) Instructor ÷ Student (c) Student – Instructor (d) Student ∪ Instructor (e) Instructor – Student.

Answers

91.	Answer : (b) Reason  :       A software application that is used to define, create, maintain and provide controlled access to user databases.
92.	Answer : (c) Reason  :       Logical data independence refers to making a change to the conceptual schema of a database but not affecting the existing external schemas.
93.	Answer : (c) Reason  :       If k is a foreign key in a relation R1, then K is a key for some other relation.
94.	Answer : (a) Reason  :       Full functional dependency is applicable with respect to 2NF.
95.	Answer : (a) Reason  :       Attribute 1  à   Attribute 3 are  the Functional dependencies that applies to the given relation.
96.	Answer : (c) Reason  :       Embedded SQL refers to writing SQL statements within codes written in a general programming language.
97.	Answer : (d) Reason  :       i).ANSI/SPARC ii) External Level iii)Internal Level iv) Conceptual Level
98.	Answer : (e) Reason  :       Employee(EmpID, BirthDate, Salary, Name(FirstName, MiddleName, LastName),SupervisorID) is the possible relation if the given ERD is mapped into a relational data model.
99.	Answer : (b) Reason  :       In the narrative description of the database requirements, verbs tend to indicate the names of relationship types.
100.	Answer : (e) Reason  :       Instructor – Student is the relational algebra operation that could be applied on the pair of relations Student and Instructor to obtain the above data.

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