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MCQOPTIONS
This section includes 1917 Mcqs, each offering curated multiple-choice questions to sharpen your UGC-NET knowledge and support exam preparation. Choose a topic below to get started.
| 1051. |
Consider the following Entity-Relationship (E-R) diagram and three possible relationship sets (I, II and III) for this E-R diagram. If different symbols stand for different values (e.g., t1 is definitely not equal to t2), then which of the above could not be the relationship set for the E-R diagram ? |
| A. | I only |
| B. | I and II only |
| C. | II only |
| D. | I, II and III |
| Answer» B. I and II only | |
| 1052. |
Consider the table R with attributes A, B and C. The functional dependencies that hold on R are : A → B, C → AB. Which of the following statements is/are True?I. The decomposition of R into R1(C, A) and R2(A, B) is lossless.II. The decomposition of R into R1(A, B) and R2(B, C) is lossy. |
| A. | Only I |
| B. | Only II |
| C. | Both I and II |
| D. | Neither I nor II |
| Answer» D. Neither I nor II | |
| 1053. |
Consider a database table R with attributes A and B. Which of the following SQL queries is illegal ? |
| A. | SELECT A FROM R; |
| B. | SELECT A, COUNT(*) FROM R; |
| C. | SELECT A, COUNT(*) FROM R GROUP BY A; |
| D. | SELECT A, B, COUNT(*) FROM R GROUP BY A, B; |
| Answer» C. SELECT A, COUNT(*) FROM R GROUP BY A; | |
| 1054. |
Let M and N be two entities in an E-R diagram with simple single valued attributes. R1 and R2 are two relationships between M and N, whereasR1 is one-to-many and R2 is many-to-many.The minimum number of tables required to represent M, N, R1 and R2 in the relational model are .......... |
| A. | 4 |
| B. | 6 |
| C. | 7 |
| D. | 3 |
| Answer» E. | |
| 1055. |
The employee information of an Organization is stored in the relation:Employee (name, sex, salary, deptname)Consider the following SQL querySelect deptname from Employee Where sex = ‘M’ group by deptname having avg (salary) > {select avg (salary) from Employee}Output of the given query corresponds to |
| A. | Average salary of employee more than average salary of the organization. |
| B. | Average salary less than average salary of the organization. |
| C. | Average salary of employee equal to average salary of the organization. |
| D. | Average salary of male employees in a department is more than average salary of the organization. |
| Answer» E. | |
| 1056. |
Which command classes text file, which has been created using “SET ALTERNATIVE” < FILE NAME > “Command” ? |
| A. | SET ALTERNATE OFF |
| B. | CLOSE DATABASE |
| C. | CLOSE ALTERNATE |
| D. | CLEAR ALL |
| Answer» B. CLOSE DATABASE | |
| 1057. |
.................. command is used to remove a relation from SQL database. |
| A. | Drop table |
| B. | Delete table |
| C. | Remove table |
| D. | Update table |
| Answer» B. Delete table | |
| 1058. |
Cross_tab displays permit users to view ................ of multidimensional data at a time. |
| A. | One dimension |
| B. | Two dimensions |
| C. | Three dimensions |
| D. | Multidimensions |
| Answer» C. Three dimensions | |
| 1059. |
Which of the following statements is TRUE?D1: The decomposition of the schema R(A,B,C) into R1(A,B) and R2(A,C) is always lossless.D2: The decomposition of the schema R(A,B,C,D,E) having AD→B, C→DE, B→AE, AE→C into R1(A,B,D) and R2(A,C,D,E) is lossless. |
| A. | Both D1 and D2 |
| B. | Neither D1 and D2 |
| C. | Only D1 |
| D. | Only D2 |
| Answer» E. | |
| 1060. |
Which one is correct w.r.t. RDBMS? |
| A. | primary key ⊆ super key ⊆ candidate key |
| B. | primary key ⊆ candidate key ⊆ super key |
| C. | super key ⊆ candidate key ⊆ primary key |
| D. | super key ⊆ primary key ⊆ candidate key |
| Answer» C. super key ⊆ candidate key ⊆ primary key | |
| 1061. |
Which of the following statement(s) is/are FALSE in the context of Relational DBMS ? I. Views in a database system are important because they help with access control by allowing users to see only a particular subset of the data in the database. II. E-R diagrams are useful to logically model concepts. III. An update anomaly is when it is not possible to store information unless some other, unrelated information is stored as well. IV. SQL is a procedural language. |
| A. | I and IV only |
| B. | III and IV only |
| C. | I, II and III only |
| D. | II, III and IV only |
| Answer» C. I, II and III only | |
| 1062. |
Specialization Lattice stands for |
| A. | An entity type can participate as a subclass in only one specialization |
| B. | An entity type can participate as a subclass in more than one specialization |
| C. | An entity type that can participate in one specialization |
| D. | An entity type that can participate in one generalization |
| Answer» C. An entity type that can participate in one specialization | |
| 1063. |
The "part-whole", or "a-part-of", relationship in which objects representing the components of something associated with an object representing the entire assembly is called as |
| A. | Association |
| B. | Aggregation |
| C. | Encapsulation |
| D. | Generalisation |
| Answer» C. Encapsulation | |
| 1064. |
Which of the following concurrency protocol ensures both conflict serializability deadlock:I. 2-phase locking II. Time phase ordering |
| A. | Both I & II |
| B. | II only |
| C. | I only |
| D. | Neither I nor II |
| Answer» C. I only | |
| 1065. |
Consider the following three tables R, S and T. In this question, all the join operations are natural joins (⨝). (π) is the projection operation of a relation. Possible answer tables for this question are also given as below.What is the resulting table of πA,B(R⨝T) ⨝ πB,C(S⨝T) ? |
| A. | (a) |
| B. | (b) |
| C. | (c) |
| D. | (d) |
| Answer» B. (b) | |
| 1066. |
Consider the schemaR = {S,T, U,V}and the dependenciesS →T, T → U, U → V and V → SIf R = (R1 and R2) be a decomposition such that R1 ∩ R2 = Фthen the decomposition is |
| A. | not in 2NF |
| B. | in 2NF but not in 3NF |
| C. | in 3NF but not in 2NF |
| D. | in both 2NF and 3NF |
| Answer» E. | |
| 1067. |
Which of the following provides the best description of an entity type? |
| A. | A specific concrete object with a defined set of processes (e.g. Jatin with diabetes) |
| B. | A value given to a particular attribute (e.g. height-230 cm) |
| C. | A thing that we wish to collect data about zero or more, possibly real world examples of it may exist |
| D. | A template for a group of things with the same set of characteristics that may exist in the real world |
| Answer» E. | |
| 1068. |
Consider the following database table :Create table test(one integer,two integer,primary key(one),unique(two),check(one≥1 and ≤10),check(two≥1 and ≤5) );How many data records/tuples atmost can this table contain ? |
| A. | 5 |
| B. | 10 |
| C. | 15 |
| D. | 50 |
| Answer» B. 10 | |
| 1069. |
The hash function used in double hashing is of the form: |
| A. | (A) h(k, i)=(h1(k)+h2(k)+i)mod m |
| B. | h(k, i)=(h1(k)+h2(k)-i)mod m |
| C. | h(k, i)=(h1(k)+ih2(k))mod m |
| D. | h(k, i)=(h1(k)-ih2(k))mod m |
| Answer» D. h(k, i)=(h1(k)-ih2(k))mod m | |
| 1070. |
A transaction can include following basic database access operations : |
| A. | Read_item(X) |
| B. | Write_item(X) |
| C. | Both (A) and (B) |
| D. | None of these |
| Answer» D. None of these | |
| 1071. |
Which of the following set of keywords constitutes a mapping in SQL? |
| A. | SELECT, FROM, TABLE |
| B. | SELECT, FROM, WHERE |
| C. | CONNECT, TABLE, CREATE |
| D. | SELECT, TABLE, INSERT |
| Answer» C. CONNECT, TABLE, CREATE | |
| 1072. |
Suppose ORACLE 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)}. Consider the following two SQL queries SQ1 and SQ2 :SQ1 : Select *From R Full Join SOn R.B=S.B;SQ2 : Select *From R Inner Join SOn R.B=S.B;The numbers of tuples in the result of the SQL query SQ1 and the SQL query SQ2 are given by : |
| A. | 2 and 6 respectively |
| B. | 6 and 2 respectively |
| C. | 2 and 4 respectively |
| D. | 4 and 2 respectively |
| Answer» E. | |
| 1073. |
A subclass having more than one super class is called ................. |
| A. | Category |
| B. | Classification |
| C. | Combination |
| D. | Partial Participation |
| Answer» B. Classification | |
| 1074. |
In multiuser database if two users wish to update the same record at the same time, they are prevented from doing so by |
| A. | Jamming |
| B. | Password |
| C. | Documentation |
| D. | Record lock |
| Answer» E. | |
| 1075. |
Match the following:(i) 5 NF (a) Transitive dependencies eliminated(ii) 2 NF (b) Multivalued attribute removed(iii) 3 NF (c) Contains no partial functional dependencies(iv) 4 NF (d) Contains no join dependency |
| A. | i-a, ii-c, iii-b, iv-d |
| B. | i-d, ii-c, iii-a, iv-b |
| C. | i-d, ii-c, iii-b, iv-a |
| D. | i-a, ii-b, iii-c, iv-d |
| Answer» C. i-d, ii-c, iii-b, iv-a | |
| 1076. |
In distributed databases, location transparency allows for database users, programmers and administrators to treat the data as if it is at one location. A SQL query with location transparency needs to specify: |
| A. | Inheritances |
| B. | Fragments |
| C. | Locations |
| D. | Local formats |
| Answer» C. Locations | |
| 1077. |
Consider the relations R(A,B) and S(B,C) and the following four relational algebra queries over R and S:I. πA,B(R⋈S)II. R⋈πB(S)III. R∩(πA(R) Χ πB(S))IV. πA,R.B(R Χ S) where R.B refers to the column B in table R.One can determine that: |
| A. | I, III and IV are the same query. |
| B. | II, III and IV are the same query. |
| C. | I, II and IV are the same query. |
| D. | I, III and III are the same query. |
| Answer» E. | |
| 1078. |
The end of an SQL command is denoted by: |
| A. | an end-of-line character |
| B. | an ‘enter-key’ marker |
| C. | entering F4 key |
| D. | a semicolon (;) |
| Answer» E. | |
| 1079. |
Which construct in SQL is used to test whether a subquery has any tuples in its result? |
| A. | UNIQUE |
| B. | EXISTS |
| C. | GROUP BY |
| D. | EXCEPT |
| Answer» C. GROUP BY | |
| 1080. |
Consider the following database table having A, B, C and D as its four attributes and four possible candidate keys (I, II, III and IV) for this table:A B C Da1 b1 c1 d1a2 b3 c3 d1a1 b2 c1 d2I: {B} II: {B, C} III: {A, D} IV: {C, D} If different symbols stand for different values in the table (e.g., d1 is definitely not equal to d2), then which of the above could not be the candidate key for the database table? |
| A. | I and III only |
| B. | III and IV only |
| C. | II only |
| D. | I only |
| Answer» D. I only | |
| 1081. |
If h is chosen from a universal collection of hash functions and is used to hash n keys into a table of size m, where n ≤ m, the expected number of collisions involving a particular key K is |
| A. | less than 1 |
| B. | less than /g n |
| C. | greater than 1 |
| D. | greater than /g n |
| Answer» B. less than /g n | |
| 1082. |
Consider a hash table of size m = 10000, and the hash function h(K)=floor(m(KAmod1)) for A = (√5 – 1)/2. The key 123456 is mapped to location ............... |
| A. | 46 |
| B. | 41 |
| C. | 43 |
| D. | 48 |
| Answer» C. 43 | |
| 1083. |
A many-to-one relationship exists between entity sets r1 and r2. How will it be represented using functional depedencies if Pk(r) denotes the primary key attribute of relation r? |
| A. | Pk(r1) → Pk(r2) |
| B. | Pk(r2) → Pk(r1) |
| C. | Pk(r2) → Pk(r1) and Pk(r1) → Pk(r2) |
| D. | Pk(r2) → Pk(r1) or Pk(r1) → Pk(r2) |
| Answer» B. Pk(r2) → Pk(r1) | |
| 1084. |
In RDBMS, which type of Join returns all rows that satisfy the join condition? |
| A. | Inner Join |
| B. | Outer Join |
| C. | Semi Join |
| D. | Anti Join |
| Answer» B. Outer Join | |
| 1085. |
In RDBMS, different classes of relations are created using ................... technique to prevent modification anomalies. |
| A. | Functional Dependencies |
| B. | Data integrity |
| C. | Referential integrity |
| D. | Normal Forms |
| Answer» E. | |
| 1086. |
Let R ={A, B, C, D, E, F} be a relation schema with the following dependencies C→F,E→A,EC→D,A→BWhich of the following is a key for R ? |
| A. | CD |
| B. | EC |
| C. | AE |
| D. | AC |
| Answer» C. AE | |
| 1087. |
Which one of the following pairs is correctly matched in the context of database design?List – I List – II(Database term) (Definition)I. Specialization A. Result of taking the union of two or more disjoint (lower-level) entity sets to produce a higher-level entity set.II. Generalization B. Express the number of entities to which another entity can be associated via a relationship set.III. Aggregation C. Result of taking a subset of a higher-level entity set to form a lower-level entity set.IV. Mapping cardinalities D. An abstraction in which relationship sets (along with their associated entity sets) are treated as higher-level entity sets, and can participate in relationships.Codes : I II III IV |
| A. | D A B C |
| B. | D C B A |
| C. | C D A B |
| D. | C A D B |
| Answer» E. | |
| 1088. |
Which of the following is an optimistic concurrency control method? |
| A. | Validation based |
| B. | Time stamp ordering |
| C. | Lock-based |
| D. | None of these |
| Answer» B. Time stamp ordering | |
| 1089. |
A WINDOW into a portion of a data base is: |
| A. | Schema |
| B. | View |
| C. | Query |
| D. | Data Dictionary |
| Answer» C. Query | |
| 1090. |
A clustering index is defined on the fields which are of type: |
| A. | non-key and ordering |
| B. | non-key and non-ordering |
| C. | key and ordering |
| D. | key and non-ordering |
| Answer» B. non-key and non-ordering | |
| 1091. |
Consider the following schedules involving two transactions.S1 : r1(X) ; r1(Y) ; r2(X) ; r2(Y) ; w2(Y) ; w1(X)S2 : r1(X) ; r2(X) ; r2(Y) ; w2(Y) ; r1(Y) ; w1(X)Which one of the following statements is correct with respect to above? |
| A. | Both S1 and S2 are conflict serializable. |
| B. | Both S1 and S2 are not conflict serializable. |
| C. | S1 is conflict serializable and S2 is not conflict serializable. |
| D. | S1 is not conflict serializable and S2 is conflict serializable. |
| Answer» E. | |
| 1092. |
Which of the following statement is wrong?I. 2-phase locking protocol suffer from dead lock.II. Time stamp protocol suffer from more aborts.III. A block hole in a DFD is a data store with only inbound flows.IV. Multivalued dependency among attribute is checked at 3 NF level.V. An entity-relationship diagram is a tool to represent event model. |
| A. | I, II, II |
| B. | II, III, IV |
| C. | III, IV, V |
| D. | II, IV, V |
| Answer» D. II, IV, V | |
| 1093. |
Select the 'False' statement from the following statements about Normal Forms : |
| A. | Lossless preserving decomposition into 3NF is always possible |
| B. | Lossless preserving decomposition into BCNF is always possible |
| C. | Any Relation with two attributes is in BCNF |
| D. | BCNF is stronger than 3NF |
| Answer» C. Any Relation with two attributes is in BCNF | |
| 1094. |
Which of the following statements is/are True regarding some advantages that an object-oriented DBMS (OODBMS) offers over a relational database?I. An OODBMS avoids the “impedance mismatch” problem.II. An OODBMS avoids the “phantom” problem.III. An OODBMS provides higher performance concurrency control than most relational databases.IV. An OODBMS provides faster access to individual data objects once they have been read from disk. |
| A. | II and III only |
| B. | I and IV only |
| C. | I, II, and III only |
| D. | I, III and IV only |
| Answer» C. I, II, and III only | |
| 1095. |
Let E1 and E2 be two entities in E-R diagram with simple single valued attributes. R1 and R2 are two relationships between E1 and E2 where R1 is one - many and R2 is many - many. R1 and R2 do not have any attribute of their own. How many minimum number of tables are required to represent this situation in the Relational Model? |
| A. | 4 |
| B. | 3 |
| C. | 2 |
| D. | 1 |
| Answer» C. 2 | |
| 1096. |
Drop Table cannot be used to drop a Table referenced by ________________ constraint.(a) Primary key (b) Sub key (c) Super key (d) Foreign key |
| A. | (a) |
| B. | (a), (b) and (c) |
| C. | (d) |
| D. | (a) and (d) |
| Answer» D. (a) and (d) | |
| 1097. |
Database applications were built directly on top of file system to overcome the following drawbacks of using file systems.(a) Data redundancy and inconsistency(b) Difficulty in accessing Data(c) Data isolation(d) Integrity problems |
| A. | (a) |
| B. | (a) and (d) |
| C. | (a), (b) and (c) |
| D. | (a), (b), (c) and (d) |
| Answer» E. | |
| 1098. |
The relation schemas R1 and R2 form a Lossless join decomposition of R if and only if :(a) R1⌒ R2 ⇒ (R1- R2)(b) R1→ R2(c) R1⌒ R2 ⇒ (R1- R2)(d) R2→ R1⌒R2 |
| A. | (a) and (b) happens |
| B. | (a) and (d) happens |
| C. | (a) and (c) happens |
| D. | (b) and (c) happens |
| Answer» D. (b) and (c) happens | |
| 1099. |
A hash table has space for 75 records, then the probability of collision before the table is 6% full. |
| A. | .25 |
| B. | .20 |
| C. | .35 |
| D. | .30 |
| Answer» C. .35 | |
| 1100. |
For a weak entity set to be meaningful, it must be associated with another entity set in combination with some of their attribute values, is called as : |
| A. | Neighbour Set |
| B. | Strong Entity Set |
| C. | Owner entity set |
| D. | Weak Set |
| Answer» D. Weak Set | |