Database Systems MCQ

 Q.1 Which of the following is correct:
(A) a SQL query automatically eliminates duplicates.
(B) SQL permits attribute names to be repeated in the same relation.
(C) a SQL query will not work if there are no indexes on the relations
(D) None of these
Ans: D

Q.2 It is better to use files than a DBMS when there are
(A) Stringent real-time requirements.
(B) Multiple users wish to access the data.
(C) Complex relationships among data.
(D) All of the above.
Ans: B

Q.3 The conceptual model is
(A) dependent on hardware.
(B) dependent on software.
(C) dependent on both hardware and software .
(D) independent of both hardware and software.
Ans: D

Q.4 What is a relationship called when it is maintained between two entities?
(A) Unary
(B) Binary
(C) Ternary
(D) Quaternary
Ans: B

Q.5 Which of the following operation is used if we are interested in only certain columns of a table?
(A) PROJECTION
(B) SELECTION
(C) UNION
(D) JOIN
Ans: A

Q.6 Which of the following is a valid SQL type?
(A) CHARACTER
(B) NUMERIC
(C) FLOAT
(D) All of the above
Ans: D

Q.7 The RDBMS terminology for a row is
(A) tuple.
(B) relation.
(C) attribute.
(D) degree.
Ans: A

Q.8 Which of the following operations need the participating relations to be union compatible?
(A) UNION
(B) INTERSECTION
(C) DIFFERENCE
(D) All of the above
Ans: D

Q.9 The full form of DDL is
(A Dynamic Data Language
(B) Detailed Data Language
(C) Data Definition Language
(D) Data Derivation Language
Ans: C

Q.10 Which of the following is an advantage of view?
(A) Data security
(B) Derived columns
(C) Hiding of complex queries
(D) All of the above
Ans: D

Q.11 Which of the following is a legal expression in SQL?
(A) SELECT NULL FROM EMPLOYEE;
(B) SELECT NAME FROM EMPLOYEE;
(C) SELECT NAME FROM EMPLOYEE WHERE SALARY = NULL;
(D) None of the above
Ans: B

Q.12 The users who use easy-to-use menu are called
(A) Sophisticated end users.
(B) Naïve users.
(C) Stand-alone users.
(D) Casual end users.
Ans: B

Q.13 Which database level is closest to the users?
(A) External
(B) Internal
(C) Physical
(D) Conceptual
Ans: A

Q.14 Which are the two ways in which entities can participate in a relationship?
(A) Passive and active
(B) Total and partial
(C) Simple and Complex
(D) All of the above
Ans: B

Q.15 The result of the UNION operation between R1 and R2 is a relation that includes
(A) all the tuples of R1
(B) all the tuples of R2
(C) all the tuples of R1 and R2
(D) all the tuples of R1 and R2 which have common columns
Ans: D

Q.16 Which of the following is a comparison operator in SQL?
(A) =
(B) LIKE
(C) BETWEEN
(D) All of the above
Ans: D

Q.17 A set of possible data values is called
(A) attribute.
(B) degree.
(C) tuple.
(D) domain.
Ans: D

Q.18 Which of the operations constitute a basic set of operations for manipulating relational data?
(A) Predicate calculus
(B) Relational calculus
(C) Relational algebra
(D) None of the above
Ans:C

Q.19 Which of the following is another name for weak entity?
(A) Child
(B) Owner
(C) Dominant
(D) All of the above
Ans: A

Q.20 Which of the following database object does not physically exist?
(A) base table
(B) index
(C) view
(D) none of the above
Ans: C

Q.21 NULL is
(A) the same as 0 for integer
(B) the same as blank for character
(C) the same as 0 for integer and blank for character
(D) not a value
Ans: D

Q.22 Which of the following is record based logical model?
(A) Network Model
(B) Object oriented model
(C) E-R Model
(D) None of these
Ans: A

Q.23 A data dictionary is a special file that contains:
(A) The name of all fields in all files.
(B) The width of all fields in all files.
(C) The data type of all fields in all files.
(D) All of the above.
Ans: D

Q.24 A file manipulation command that extracts some of the records from a file is called
(A) SELECT
(B) PROJECT
(C) JOIN
(D) PRODUCT
Ans: A

Database Systems MCQ

 Q.1 The DBMS language component which can be embedded in a program is
(A) The data definition language (DDL).
(B) The data manipulation language (DML).
(C) The database administrator (DBA).
(D) A query language.
Ans: B

Q.2 A relational database developer refers to a record as
(A) a criteria.
(B) a relation.
(C) a tuple.
(D) an attribute.
Ans: C

Q.3 The relational model feature is that there
(A) is no need for primary key data.
(B) is much more data independence than some other database models.
(C) are explicit relationships among records.
(D) are tables with many dimensions.
Ans: B

Q.4 Conceptual design
(A) is a documentation technique.
(B) needs data volume and processing frequencies to determine the size of the database.
(C) involves modelling independent of the DBMS.
(D) is designing the relational model.
Ans:C

Q.5 The method in which records are physically stored in a specified order according to a key field in each record is
(A) hash.
(B) direct.
(C) sequential.
(D) all of the above.
Ans: A A method in which records are physically stored in a specified order according to a key field in each record is hash.
(In hash method, a hash function is performed on the key value to determine the unique physical address of the record to store or retrieve)

Q.6 A subschema expresses
(A) the logical view.
(B) the physical view.
(C) the external view.
(D) all of the above.
Ans: C A subschema expresses the external view.
(External schemas are called also called as subschemas)

Q.7 Count function in SQL returns the number of
(A) values.
(B) distinct values.
(C) groups.
(D) columns.
Ans: A Count function in SQL returns the number of values.
(Count function counts all the not null values in the specific column. If we want to count only distinct values than the DISTINCT keyword is also to be used)

Q.8 Which one of the following statements is false?
(A) The data dictionary is normally maintained by the database administrator.
(B) Data elements in the database can be modified by changing the data dictionary.
(C) The data dictionary contains the name and description of each data element.
(D) The data dictionary is a tool used exclusively by the database administrator.
Ans: B

Q.9 An advantage of the database management approach is
(A) data is dependent on programs.
(B) data redundancy increases.
(C) data is integrated and can be accessed by multiple programs.
(D) none of the above.
Ans: C

Q.10 A DBMS query language is designed to
(A) support end users who use English-like commands.
(B) support in the development of complex applications software.
(C) specify the structure of a database.
(D) all of the above.
Ans: D

Q.11 Transaction processing is associated with everything below except
(A) producing detail, summary, or exception reports.
(B) recording a business activity.
(C) confirming an action or triggering a response.
(D) maintaining data.
Ans: C

Q.12 It is possible to define a schema completely using
(A) VDL and DDL.
(B) DDL and DML.
(C) SDL and DDL.
(D) VDL and DML.
Ans: B

Q.13 The method of access which uses key transformation is known as
(A) direct.
(B) hash.
(C) random.
(D) sequential.
Ans: B

Q.14 Data independence means
(A) data is defined separately and not included in programs.
(B) programs are not dependent on the physical attributes of data.
(C) programs are not dependent on the logical attributes of data.
(D) both (B) and (C).
Ans: D both (B) and (C)

Q.15 The statement in SQL which allows to change the definition of a table is
(A) Alter.
(B) Update.
(C) Create.
(D) select.
Ans: A

Q.16 E-R model uses this symbol to represent weak entity set ?
(A) Dotted rectangle.
(B) Diamond
(C) Doubly outlined rectangle
(D) None of these
Ans: C

Q.17 SET concept is used in :
(A) Network Model
(B) Hierarchical Model
(C) Relational Model
(D) None of these
Ans: A

Q.18 Relational Algebra is
(A) Data Definition Language .
(B) Meta Language
(C) Procedural query Language
(D) None of the above
Ans: C

Q.19 Key to represent relationship between tables is called
(A) Primary key
(B) Secondary Key
(C) Foreign Key
(D) None of these
Ans: C

Q.20 _______ produces the relation that has attributes of R1 and R2
(A) Cartesian product
(B) Difference
(C) Intersection
(D) Product
Ans: A

Q.21 The file organization that provides very fast access to any arbitrary record of a file is
(A) Ordered file
(B) Unordered file
(C) Hashed file
(D) B-tree
Ans: C

Q.22 DBMS helps achieve
(A) Data independence
(B) Centralized control of data
(C) Neither (A) nor (B)
(D) both (A) and (B)
Ans: D

Q.23 Which of the following are the properties of entities?
(A) Groups
(B) Table
(C) Attributes
(D) Switchboards
Ans: C

Q.24 In a relation
(A) Ordering of rows is immaterial
(B) No two rows are identical
(C) (A) and (B) both are true
(D) None of these.
Ans: C