This post includes the latest 151 questions and answers related to the database management system. Latest MCQ questions.
- A relational database consists of a collection of
a) Tables
b) Fields
c) Records
d) Keys
e) none of these - A __ in a table represents a relationship among a set of values.
a) Column
b) Key
c) Row
d) Entry
e) none of these b - The term _ is used to refer to a row.
a) Attribute
b) Tuple
c) Field
d) Instance
e) none of these - The term attribute refers to a _ of a table.
a) Record
b) Column
c) Tuple
d) Key
e) none of these - For each attribute of a relation, there is a set of permitted values, called the __ of that attribute.
a) Domain
b) Relation
c) Set
d) Schema
e) none of these - Database __ which is the logical design of the database, and the database _ which is a snapshot of the data in the database at a given instant in time.
a) Instance, Schema
b) Relation, Schema
c) Relation, Domain
d) Schema, Instance
e) none of these - Course(course_id,sec_id,semester)
Here the course_id,sec_id and semester are _ and course is a
a) Relations, Attribute
b) Attributes, Relation
c) Tuple, Relation
d) Tuple, Attributes
e) none of these - Department (dept name, building, budget) and Employee (employee_id, name, dept name, salary)
Here the dept_name attribute appears in both the relations. Here using common attributes in relation schema is one way of relating _ relations.
a) Attributes of common
b) Tuple of common
c) Tuple of distinct
d) Attributes of distinct
e) none of these - A domain is atomic if elements of the domain are considered to be __ units.
a) Different
b) Indivisbile
c) Constant
d) Divisible
e) none of these - The tuples of the relations can be of __ order.
a) Any
b) Same
c) Sorted
d) Constant
e) none of these
- Which of the following gives a logical structure of the database graphically?
a) Entity-relationship diagram
b) Entity diagram
c) Database diagram
d) Architectural representation
e) none of these - The entity relationship set is represented in E-R diagram as
a) Double diamonds
b) Undivided rectangles
c) Dashed lines
d) Diamond
e) none of these - The Rectangles divided into two parts represents
a) Entity set
b) Relationship set
c) Attributes of a relationship set
d) Primary key
e) none of these - Consider a directed line(->) from the relationship set advisor to both entity sets instructor and student. This indicates _ cardinality
a) One to many
b) One to one
c) Many to many
d) Many to one
e) none of these - We indicate roles in E-R diagrams by labeling the lines that connect to ___
a) Diamond , diamond
b) Rectangle, diamond
c) Rectangle, rectangle
d) Diamond, rectangle
e) none of these - An entity set that does not have sufficient attributes to form a primary key is termed a __
a) Strong entity set
b) Variant set
c) Weak entity set
d) Variable set
e) none of these - For a weak entity set to be meaningful, it must be associated with another entity set, called the
a) Identifying set
b) Owner set
c) Neighbour set
d) Strong entity set
e) none of these - Weak entity set is represented as
a) Underline
b) Double line
c) Double diamond
d) Double rectangle
e) none of these - If you were collecting and storing information about your music collection, an album would be considered a(n) _
a) Relation
b) Entity
c) Instance
d) Attribute
e) none of these - What term is used to refer to a specific record in your music database; for instance; information stored about a specific album?
a) Relation
b) Instance
c) Table
d) Column
e) none of these
- To include integrity constraint in an existing relation use :
a) Create table
b) Modify table
c) Alter table
d) Drop table
e) none of these - Which of the following is not an integrity constraint?
a) Not null
b) Positive
c) Unique
d) Check ‘predicate’
e) none of these
23.
CREATE TABLE Employee(Emp_id NUMERIC NOT NULL, Name VARCHAR(20) , dept_name VARCHAR(20), Salary NUMERIC UNIQUE(Emp_id,Name));
INSERT INTO Employee VALUES(1002, Ross, CSE, 10000)
INSERT INTO Employee VALUES(1006,Ted,Finance, );
INSERT INTO Employee VALUES(1002,Rita,Sales,20000);
What will be the result of the query?
a) All statements executed
b) Error in create statement
c) Error in insert into Employee values(1006,Ted,Finance, );
d) Error in insert into Employee values(1008,Ross,Sales,20000);
e) none of these
24.
CREATE TABLE Manager(ID NUMERIC,Name VARCHAR(20),budget NUMERIC,Details VARCHAR(30));
In order to ensure that the value of the budget is non-negative which of the following should be used?
a) Check(budget>0)
b) Check(budget<0) c) Alter(budget>0)
d) Alter(budget<0)
e) none of these
- Foreign key is the one in which the __ of one relation is referenced in another relation.
a) Foreign key
b) Primary key
c) References
d) Check constraint
e) none of these
26.
CREATE TABLE course
( . . .
FOREIGN KEY (dept name) REFERENCES department
. . . );
Which of the following is used to delete the entries in the referenced table when the tuple is deleted in the course table?
a) Delete
b) Delete cascade
c) Set null
d) All of the mentioned
e) None of these
- Domain constraints, functional dependency and referential integrity are special forms of _
a) Foreign key
b) Primary key
c) Assertion
d) Referential constraint
e) none of these - Which of the following is the right syntax for the assertion?
a) Create assertion ‘assertion-name’ check ‘predicate’;
b) Create assertion check ‘predicate’ ‘assertion-name’;
c) Create assertions ‘predicates’;
d) All of the mentioned
e) none of these - Data integrity constraints are used to:
a) Control who is allowed access to the data
b) Ensure that duplicate records are not entered into the table
c) Improve the quality of data entered for a specific property (i.e., table column)
d) Prevent users from changing the values stored in the table
e) none of these - Which of the following can be addressed by enforcing a referential integrity constraint?
a) All phone numbers must include the area code
b) Certain fields are required (such as the email address, or phone number) before the record is accepted
c) Information on the customer must be known before anything can be sold to that customer
d) When entering an order quantity, the user must input a number and not some text (i.e., 12 rather than ‘a dozen’)
e) none of these - In the __ normal form, a composite attribute is converted to individual attributes.
a) First
b) Second
c) Third
d) Fourth
e) none of these - A table on the many side of a one to many or many to many relationship must:
a) Be in Second Normal Form (2NF)
b) Be in Third Normal Form (3NF)
c) Have a single attribute key
d) Have a composite key
e) none of these - Tables in second normal form (2NF):
a) Eliminate all hidden dependencies
b) Eliminate the possibility of a insertion anomalies
c) Have a composite key
d) Have all non key fields depend on the whole primary key
e) none of these - Which-one ofthe following statements about normal forms is FALSE?
a) BCNF is stricter than 3 NF
b) Lossless, dependency -preserving decomposition into 3 NF is always possible
c) Loss less, dependency – preserving decomposition into BCNF is always possible
d) Any relation with two attributes is BCNF
e) none of these - Functional Dependencies are the types of constraints that are based on______
a) Key
b) Key revisited
c) Superset key
d)unique key
e) None of the mentioned - Which is a bottom-up approach to database design that design by examining the relationship between attributes:
a) Functional dependency
b) Database modeling
c) Normalization
d) Decomposition
e) none of these - Which forms simplifies and ensures that there are minimal data aggregates and repetitive groups:
a) 1NF
b) 2NF
c) 3NF
d) All of the mentioned
e) none of these - Which forms has a relation that possesses data about an individual entity:
a) 2NF
b) 3NF
c) 4NF
d) 5NF
e) none of these - Which forms are based on the concept of functional dependency:
a) 1NF
b) 2NF
c) 3NF
d) 4NF
e) none of these
40.
Empdt1(empcode, name, street, city, state, Pincode).
For any Pincode, there is only one city and state. Also, forgive the street, city, and state, there is just one Pincode. In normalization terms, empdt1 is a relation in
a) 1 NF only
b) 2 NF and hence also in 1 NF
c) 3NF and hence also in 2NF and 1NF
d) BCNF and hence also in 3NF, 2NF, and 1NF
e) None of these
- We can use the following three rules to find logically implied functional dependencies. This collection of rules is called
a) Axioms
b) Armstrong’s axioms
c) Armstrong
d) Closure
e) none of these - Which of the following is not Armstrong’s Axiom?
a) Reflexivity rule
b) Transitivity rule
c) Pseudotransitivity rule
d) Augmentation rule
e) none of these - The relation employee(ID,name,street,Credit,street,city,salary) is decomposed into
employee1 (ID, name)
employee2 (name, street, city, salary)
This type of decomposition is called
a) Lossless decomposition
b) Lossless-join decomposition
c) All of the mentioned
d) None of the mentioned - Inst_dept (ID, name, salary, dept name, building, budget) is decomposed into
instructor (ID, name, dept name, salary)
department (dept name, building, budget)
This comes under
a) Lossy-join decomposition
b) Lossy decomposition
c) Lossless-join decomposition
d) Both Lossy and Lossy-join decomposition
e) none of these - There are two functional dependencies with the same set of attributes on the left side of the arrow:
A->BC
A->B
This can be combined as
a) A->BC
b) A->B
c) B->C
d) None of the mentioned - Consider a relation R(A,B,C,D,E) with the following functional dependencies:
ABC -> DE and
D -> AB
The number of superkeys of R is:
a) 2
b) 7
c) 10
d) 12
e) none of these - Suppose we wish to find the ID’s of the employees that are managed by people who are managed by the employee with ID 123. Here are two possible queries:
I.SELECT ee.empID
FROM Emps ee, Emps ff
WHERE ee.mgrID = ff.empID AND ff.mgrID = 123;
II.SELECT empID
FROM Emps
WHERE mgrID IN
(SELECT empID FROM Emps WHERE mgrID = 123);
Which, if any, of the two queries above will correctly (in SQL2) get the desired set of employee ID’s?
a) Both I and II
b) I only
c) II only
d) None of these - Suppose relation R(A,B) currently has tuples {(1,2), (1,3), (3,4)} and relation S(B,C) currently has {(2,5), (4,6), (7,8)}. Then the number of tuples in the result of the SQL query:
SELECT * FROM R NATURAL OUTER JOIN S
a) 2
b) 4
c) 6
d) None of the mentioned - Suppose now that R(A,B) and S(A,B) are two relations with r and s tuples, respectively (again, not necessarily distinct). If m is the number of (not necessarily distinct) tuples in the result of the SQL query:
R intersect S;
Then which of the following is the most restrictive, correct condition on the value of m?
a) m = min(r,s)
b) 0 <= m <= r + s
c) min(r,s) <= m <= max(r,s)
d) 0 <= m <= min(r,s)
e) none of these - Suppose relation R(A,B,C,D,E) has the following functional dependencies:
A -> B
B -> C
BC -> A
A -> D
E -> A
D -> E
Which of the following is not a key?
a) A
b) E
c) B, C
d) D
e) none of these - Relational Algebra is a __ query language that takes two relations as input and produces another relation as an output of the query.
a) Relational
b) Structural
c) Procedural
d) Fundamental
e) none of these - Which of the following is a fundamental operation in relational algebra?
a) Set intersection
b) Natural join
c) Assignment
d) None of the mentioned
e) none of these - Which of the following is used to denote the selection operation in relational algebra?
a) Pi (Greek)
b) Sigma (Greek)
c) Lambda (Greek)
d) Omega (Greek)
e) none of these - For select operation the appear in the subscript and the _ argument appears in the paranthesis after the sigma.
a) Predicates, relation
b) Relation, Predicates
c) Operation, Predicates
d) Relation, Operation
e) none of these - The _ operation, denoted by −, allows us to find tuples that are in one relation but are not in another.
a) Union
b) Set-difference
c) Difference
d) Intersection
e) none of these - Which is a unary operation:
a) Selection operation
b) Primitive operation
c) Projection operation
d) Generalized selection
e) none of these - Which is a join condition contains an equality operator:
a) Equijoins
b) Cartesian
c) Natural
d) Left
e) none of these - In precedence of set operators, the expression is evaluated from
a) Left to left
b) Left to right
c) Right to left
d) From user specification
e) none of these - Which of the following is not outer join?
a) Left outer join
b) Right outer join
c) Full outer join
d) All of the mentioned
e) none of these - The assignment operator is denoted by
a) ->
b) <-
c) =
d) ==
e) none of these - Aggregate functions are functions that take a _ as input and return a single value.
a) Collection of values
b) Single value
c) Aggregate value
d) Both Collection of values & Single value
e) none of these - SELECT __________FROM instructor WHERE dept name= ’Comp. Sci.’;
Which of the following should be used to find the mean of the salary?
a) Mean(salary)
b) Avg(salary)
c) Sum(salary)
d) Count(salary)
e) none of these - SELECT COUNT (_ ID) FROM teaches WHERE semester = ’Spring’ AND YEAR = 2010; If we do want to eliminate duplicates, we use the keyword _ in the aggregate expression.
a) Distinct
b) Count
c) Avg
d) Primary key
e) none of these - All aggregate functions except _ ignore null values in their input collection.
a) Count (attribute)
b) Count(*)
c) Avg
d) Sum
e) none of these - The EXISTS keyword will be true if:
a) Any row in the subquery meets the condition only
b) All rows in the subquery fail the condition only
c) Both of these two conditions are met
d) none of these - The _ connective tests for set membership, where the set is a collection of values produced by a select clause. The _ connective tests for the absence of set membership.
a) Or, in
b) Not in, in
c) In, not in
d) In, or
e) none of these - Which of the following should be used to find all the courses taught in the Fall 2009 semester but not in the Spring 2010 semester.
a) SELECT DISTINCT course id FROM SECTION WHERE semester = ’Fall’ AND YEAR= 2009 AND course id NOT IN (SELECT course id FROM SECTION WHERE semester = ’Spring’ AND YEAR= 2010);
b) SELECT DISTINCT course_id FROM instructor WHERE name NOT IN (’Fall’, ’Spring’);
c) (SELECT course idFROM SECTIONWHERE semester = ’Spring’ AND YEAR= 2010)
d) SELECT COUNT (DISTINCT ID) FROM takesWHERE (course id, sec id, semester, YEAR) IN (SELECT course id, sec id, semester, YEARFROM teachesWHERE teaches.ID= 10101);
e) none of these - How many tables may be included with a join?
a) One
b) Two
c) Three
d) All the above
e) none of these - The SQL WHERE clause
a) Limits the column data that are returned
b) Limits the row data are returned
c) Both A and B are correct.
d) none of these - We can test for the nonexistence of tuples in a subquery by using the _ construct.
a) Not exist
b) Not exists
c) Exists
d) Exist
e) none of these
Answer: b
- Which of the following creates a virtual relation for storing the query?
a) Function
b) View
c) Procedure
d) None of the mentioned - Which of the following is the syntax for views where v is view name?
a) Create view v as “query name”;
b) Create “query expression” as view;
c) Create view v as “query expression”;
d) Create view “query expression”;
e) none of these
73.
SELECT course_id
FROM physics_fall_2009
WHERE building= ’Watson’;
Here the tuples are selected from the view. Which one denotes the view.
a) Course_id
b) Watson
c) Building
d) physics_fall_2009
e) None of these
- Materialised views make sure that
a) View definition is kept stable
b) View definition is kept up-to-date
c) View definition is verified for error
d) View is deleted after specified time
e) none of these - Updating the value of the view
a) Will affect the relation from which it is defined
b) Will not change the view definition
c) Will not affect the relation from which it is defined
d) Cannot determine
e) none of these - A __ is a special kind of a store procedure that executes in response to certain action on the table like insertion, deletion or updation of data.
a) Procedures
b) Triggers
c) Functions
d) None of the mentioned - Triggers are supported in
a) Delete
b) Update
c) Views
d) All of the mentioned
e) none of these - The CREATE TRIGGER statement is used to create the trigger. THE _ clause specifies the table name on which the trigger is to be attached. The __ specifies that this is an AFTER INSERT trigger.
a) for insert, on
b) On, for insert
c) For, insert
d) None of the mentioned - What are the after triggers?
a) Triggers generated after a particular operation
b) These triggers run after an insert, update or delete on a table
c) These triggers run after an insert, views, update or delete on a table
d) All of the mentioned
e) none of these - The variables in the triggers are declared using
a) –
b) @
c) /
d) /@
e) none of these - The default extension for an Oracle SQL*Plus file is:
a) .txt
b) .pls
c) .ora
d) .sql
e) none of these - Which one of the following is a set of one or more attributes taken collectively to uniquely identify a record?
a) Candidate key
b) Sub key
c) Super key
d) Foreign key
e) none of these - Consider attributes ID, CITY and NAME. Which one of this can be considered as a super key?
a) NAME
b) ID
c) CITY
d) CITY, ID
e) none of these - The subset of a super key is a candidate key under what condition?
a) No proper subset is a super key
b) All subsets are super keys
c) Subset is a super key
d) Each subset is a super key
e) none of these - A _ is a property of the entire relation, rather than of the individual tuples in which each tuple is unique.
a) Rows
b) Key
c) Attribute
d) Fields
e) none of these - Which one of the following attribute can be taken as a primary key?
a) Name
b) Street
c) Id
d) Department
e) none of these - Which one of the following cannot be taken as a primary key?
a) Id
b) Register number
c) Dept_id
d) Street
e) none of these - An attribute in a relation is a foreign key if the _ key from one relation is used as an attribute in that relation.
a) Candidate
b) Primary
c) Super
d) Sub
e) none of these - The relation with the attribute which is the primary key is referenced in another relation. The relation which has the attribute as a primary key is called __
a) Referential relation
b) Referencing relation
c) Referenced relation
d) Referred relation
e) none of these - The __ is the one in which the primary key of one relation is used as a normal attribute in another relation.
a) Referential relation
b) Referencing relation
c) Referenced relation
d) Referred relation
e) none of these - In ordered indices the file containing the records is sequentially ordered, a _ is an index whose search key also defines the sequential order of the file.
a) Clustered index
b) Structured index
c) Unstructured index
d) Nonclustered index
e) none of these - Indices whose search key specifies an order different from the sequential order of the file are called _ indices.
a) Nonclustered
b) Secondary
c) All of the mentioned
d) None of the mentioned - An __ consists of a search-key value and pointers to one or more records with that value as their search-key value.
a) Index entry
b) Index hash
c) Index cluster
d) Index map
e) none of these - In a _ clustering index, the index record contains the search-key value and a pointer to the first data record with that search-key value and the rest of the records will be in the sequential pointers.
a) Dense
b) Sparse
c) Straight
d) Continuous
e) none of these - In a __ index, an index entry appears for only some of the search-key values.
a) Dense
b) Sparse
c) Straight
d) Continuous
e) none of these - Incase the indices values are larger, index is created for these values of the index. This is called
a) Pointed index
b) Sequential index
c) Multilevel index
d) Multiple index
e) none of these - A search key containing more than one attribute is referred to as a _ search key.
a) Simple
b) Composite
c) Compound
d) Secondary
e) none of these - In B+ tree the node which points to another node is called
a) Leaf node
b) External node
c) Final node
d) Internal node
e) none of these - Insertion of a large number of entries at a time into an index is referred to as __ of the index.
a) Loading
b) Bulk insertion
c) Bulk loading
d) Increase insertion
e) none of these - While inserting the record into the index, if the search-key value does not appear in the index.
a) The system adds a pointer to the new record in the index entry
b) The system places the record being inserted after the other records with the same search-key values
c) The system inserts an index entry with the search-key value in the index at the appropriate position
d) None of the mentioned - What is the purpose of the index in sql server?
a) To enhance the query performance
b) To provide an index to a record
c) To perform fast searches
d) All of the mentioned
e) none of these - How many types of indexes are there in sql server?
a) 1
b) 2
c) 3
d) 4
e) none of these - How non clustered index point to the data?
a) It never points to anything
b) It points to a data row
c) It is used for pointing data rows containing key values
d) None of the mentioned - Which one is true about clustered index?
a) Clustered index is not associated with table
b) Clustered index is built by default on unique key columns
c) Clustered index is not built on unique key columns
d) none of these - What is true about indexes?
a) Indexes enhance the performance even if the table is updated frequently
b) It makes harder for sql server engines to work to work on index which have large keys
c) It doesn’t make harder for sql server engines to work to work on index which have large keys
d) none of these - Does index take space in the disk?
a) It stores memory as and when required
b) Yes, Indexes are stored on disk
c) Indexes are never stored on disk
d) Indexes take no space
e) none of these - What are composite indexes?
a) Are those which are composed by database for its internal use
b) A composite index is a combination of index on 2 or more columns
c) Composite index can never be created
d) None of the mentioned - If an index is _____ the metadata and statistics continue to exists
a) Disabling
b) Dropping
c) Altering
d) Both Disabling and Dropping
e) none of these - In ___ index instead of storing all the columns for a record together, each column is stored separately with all other rows in an index.
a) Clustered
b) Column store
c) Non clustered
d) Row store
e) none of these - A _____ index is the one which satisfies all the columns requested in the query without performing further lookup into the clustered index.
a) Clustered
b) Non Clustered
c) Covering
d) B-Tree
e) none of these - A collection of data designed to be used by different people is called a/an
a) Organization
b) Database
c) Relationship
d) Schema
e) none of these - Which of the following is the oldest database model?
a) Relational
b) Deductive
c) Physical
d) Network
e) none of these - Which of the following schemas does define a view or views of the database for particular users?
a) Internal schema
b) Conceptual schema
c) Physical schema
d) External schema
e) none of these - Which of the following is an attribute that can uniquely identify a row in a table?
a) Secondary key
b) Candidate key
c) Foreign key
d) Alternate key
e) none of these - Which of the following are the process of selecting the data storage and data access characteristics of the database?
a) Logical database design
b) Physical database design
c) Testing and performance tuning
d) Evaluation and selecting
e) none of these - Which of the following terms does refer to the correctness and completeness of the data in a database?
a) Data security
b) Data constraint
c) Data independence
d) Data integrity
e) none of these - The relationship between DEPARTMENT and EMPLOYEE is a
a) One-to-one relationship
b) One-to-many relationship
c) Many-to-many relationship
d) Many-to-one relationship
e) none of these - A table can be logically connected to another table by defining a
a) Super key
b) Candidate key
c) Primary key
d) Unique key
e) none of these - If the state of the database no longer reflects a real state of the world that the database is supposed to capture, then such a state is called
a) Consistent state
b) Parallel state
c) Durable state
d) Inconsistent state
e) none of these - Ensuring isolation property is the responsibility of the
a) Recovery-management component of the DBMS
b) Concurrency-control component of the DBMS
c) Transaction-management component of the DBMS
d) Buffer management component in DBMS
e) none of these - Consider money is transferred from (1)account-A to account-B and (2) account-B to account-A. Which of the following form a transaction?
a) Only 1
b) Only 2
c) Both 1 and 2 individually
d) Either 1 or 2
e) none of these - A transaction is delimited by statements (or function calls) of the form __
a) Begin transaction and end transaction
b) Start transaction and stop transaction
c) Get transaction and post transaction
d) Read transaction and write transaction
e) none of these - Identify the characteristics of transactions
a) Atomicity
b) Durability
c) Isolation
d) All of the mentioned
e) none of these - Which of the following has “all-or-none” property?
a) Atomicity
b) Durability
c) Isolation
d) All of the mentioned
e) none of these - The database system must take special actions to ensure that transactions operate properly without interference from concurrently executing database statements. This property is referred to as
a) Atomicity
b) Durability
c) Isolation
d) All of the mentioned
e) none of these - The property of a transaction that persists all the crashes is
a) Atomicity
b) Durability
c) Isolation
d) All of the mentioned
e) none of these - __ states that only valid data will be written to the database.
a) Consistency
b) Atomicity
c) Durability
d) Isolation
e) none of these - Consider the transactions T1, T2, and T3 and the schedules S1 and S2 given below.
T1: r1(X); r1(Z); w1(X); w1(Z)
T2: r2(Y); r2(Z); w2(Z)
T3: r3(Y); r3(X); w3(Y)
S1: r1(X); r3(Y); r3(X); r2(Y); r2(Z);
w3(Y); w2(Z); r1(Z); w1(X); w1(Z)
S2: r1(X); r3(Y); r2(Y); r3(X); r1(Z);
r2(Z); w3(Y); w1(X); w2(Z); w1(Z)
Which one of the following statements about the schedules is TRUE?
a) Only S1 is conflict-serializable
b) Only S2 is conflict-serializable
c) Both S1 and S2 are conflict-serializable
d) Neither S1 nor S2 is conflict-serializable
e) None of these
- The Oracle RDBMS uses the __ statement to declare a new transaction start and its properties.
a) BEGIN
b) SET TRANSACTION
c) BEGIN TRANSACTION
d) COMMIT
e) none of these - __ means that the data used during the execution of a transaction cannot be used by a second transaction until the first one is completed.
a) Consistency
b) Atomicity
c) Durability
d) Isolation
e) none of these
131 . If a schedule is equivalent to a serial schedule, it is called as a _
a) Serializable schedule
b) Equivalent schedule
c) Committed schedule
d) serial sechedule
e) None of these
- A lock that allows concurrent transactions to access different rows of the same table is known as a
a) Database-level lock
b) Table-level lock
c) Page-level lock
d) Row-level lock
e) none of these - Which of the following are introduced to reduce the overheads caused by the log-based recovery?
a) Checkpoints
b) Indices
c) Deadlocks
d) Locks
e) none of these - Which of the following protocols ensures conflict serializability and safety from deadlocks?
a) Two-phase locking protocol
b) Time-stamp ordering protocol
c) Graph based protocol
d) None of the mentioned - How many serial schedules are possible using n-transactions?
a) (n-1)!
b) n!
c) n(n-1)!
d) n(n+1)! / 2
e) None of these - If transaction Ti gets an explicit lock on the file Fc in exclusive mode, then it has an ¬¬¬¬¬-__ on all the records belonging to that file.
a) Explicit lock in exclusive mode
b) Implicit lock in shared mode
c) Explicit lock in shared mode
d) Implicit lock in exclusive mode
e) none of these - Which refers to a property of computer to run several operation simultaneously and possible as computers await response of each other
a) Concurrency
b) Deadlock
c) Backup
d) Recovery
e) none of these - All lock information is managed by a __ which is responsible for assigning and policing the locks used by the transactions.
a) Scheduler
b) DBMS
c) Lock manager
d) Locking agent
e) none of these - The __ lock allows concurrent transactions to access the same row as long as they require the use of different fields within that row.
a) Table-level
b) Page-level
c) Row-level
d) Field-level
e) none of these - Which of the following is a procedure for acquiring the necessary locks for a transaction where all necessary locks are acquired before any are released?
a) Record controller
b) Exclusive lock
c) Authorization rule
d) Two phase lock
e) none of these
Answer: d - The log is a sequence of _ recording all the update activities in the database.
a) Log records
b) Records
c) Entries
d) Redo
e) none of these - In the _ scheme, a transaction that wants to update the database first creates a complete copy of the database.
a) Shadow copy
b) Shadow Paging
c) Update log records
d) All of the mentioned
e) none of these - The __ scheme uses a page table containing pointers to all pages; the page table itself and all updated pages are copied to a new location.
a) Shadow copy
b) Shadow Paging
c) Update log records
d) All of the mentioned
e) none of these - The current copy of the database is identified by a pointer, called __ which is stored on disk.
a) Db-pointer
b) Update log
c) Update log records
d) All of the mentioned
e) none of these - If a transaction does not modify the database until it has committed, it is said to use the _ technique.
a) Deferred-modification
b) Late-modification
c) Immediate-modification
d) Undo
e) none of these - If database modifications occur while the transaction is still active, the transaction is said to use the ___________technique.
a) Deferred-modification
b) Late-modification
c) Immediate-modification
d) Undo
e) none of these - __ using a log record sets the data item specified in the log record to the old value.
a) Deferred-modification
b) Late-modification
c) Immediate-modification
d) Undo
e) none of these - In the __ phase, the system replays updates of all transactions by scanning the log forward from the last checkpoint.
a) Repeating
b) Redo
c) Replay
d) Undo
e) none of these - The actions which are played in the order while recording it is called __ history.
a) Repeating
b) Redo
c) Replay
d) Undo
e) none of these
150.which of the following schedule are not conflict serializable?
a) r₁(A); w₁(A); r₂ (A); w₂(A); w₁(B)
b) r₁(A); r₁ (B); w₂(A); r₃(A); w₁(B); w₃(A); r₂ (B); w₂ (B)
c) r₁(A); w₁(A); r₂ (A); w₂(A); w₁(B)
d) w₃ (A); r₁ (A); w₁ (B); r₂ (B); w₂(c); r₃ (c)
e) None of these
- Which three is true regarding the use of outer joins?
a) You cannot use IN operator in a condition that involves an outer join.
b) You use an outer join to see only the rows that do not meet the join condition.
c) In the WHERE condition, you use (+) following the name of the column in the table without matching rows, to perform an outer join.
d) You cannot link a condition that is involved in an outer join to another condition by using the OR operator.
e) None of the these
Answer
1.(a)
2.(c)
3.(b)
4.(b)
5.(a)
6.(d)
7.(b)
8.(c)
9.(b)
10.(a)
11.(a)
12.(d)
13.(a)
14.(b)
15.(d)
16.(c)
17.(a)
18.(c)
19.(b)
20.(b)
21.(c)
22.(b)
23.(d)
24.(a)
25.(b)
26.(b)
27.(c)
28.(a)
29.(c)
30.(c)
31.(a)
32.(d)
33.(a)
34.(c)
35.(a)
36.(c)
37.(c)
38.(c)
39.(c)
40.(b)
41.(b)
42.(c)
43.(d)
44.(d)
45.(a)
46.(c)
47.(a)
48.(a)
49.(d)
50.(c)
51.(c)
52.(d)
53.(b)
54.(a)
55.(b)
56.(d)
57.(a)
58.(b)
59.(d)
60.(b)
61.(a)
62.(b)
63.(a)
64.(b)
65.(a)
66.(c)
67.(a)
68.(d)
69.(b)
70.(b)
71.(b)
72.(c)
73.(c)
74.(b)
75.(a)
76.(b)
77.(c)
78.(b)
79.(b)
80.(b)
81(d)
82(c)
83(b)
84(a)
85(b)
86(c)
87(d)
88-b
89-c
90-c
91-a
92-c
93-a
94-a
95-a
96-c
97-b
98-d
99-c
100-c
101-d
102-b
103-c
104-b
105-b
106-b
107-b
108-a
109-b
110-c
110-b
112-d
113-d
114-b
115-b
116-d
117-b
118-c
119-d
120-b
121-c
122-a
123-a
124-a
125-c
126-b
127-a
128-a
129-b
130-d
131-a
132-d
133-a
134-b
135-b
136-d
137-a
138-c
139-d
140-d
141-a
142-a
143-b
144-a
145-a
146-c
147-d
148-b
149-a
150-d
151-a,c,d