CBSE Class 12 Computer Science Sql Worksheet Set 02

I. Multiple choice Questions:

Question. A Database contains one or more_______
a) Data
b) Tables
c) Files
d) Links
Answer. B

Question. A ............ is an organized collection of structured data.
a) Database
b) File
c) DBMS
d) Information
Answer. A

Question. A data ................ is a set of rules that define valid data.
a) Query
b) Constraint
c) Dictionary
d) All of the above
Answer. B

Question. What is not true in respect of DBMS?
a) Database enforces standards
b) Database increases redundancy
c) Database facilitates sharing of data
d) Database helps to maintain integrity
Answer. B

Question. Cardinality is total ___________
a) number of rows in a table
b) number of columns in a table
c) number of data items in a table
d) none of the above
Answer. A

Question. To fetch one record from resultset you may use<curor>………… method.
a) fetch()
b) fetchone()
c) fetchtuple
d) none of these.
Answer. B

Question. To reflect the changes made in the database permanently you need to run……..
a) done()
b) reflect()
c) commit()
d) final
Answer. C

Question. Data about data is _________
a) Data redundancy
b) Meta Data
c) Database schema
d) None of the above
Answer. B

Question. Repetition of data is called ..............
a) Data redundancy
b) Data Description
c) Data inconsistency
d) None of the above
Answer. A

Question. Which of the following statements is not true about relational database?
a) Relational data model is the most widely used data model.
b) The data is arranged as a collection of tables in relational database.
c) Relational database increases data redundancy and inconsistency.
d) None of the above.
Answer. C

Question. The term ____________ is used to refer to a field in a table.
a) Attribute
b) Row
c) Tuple
d) Instance
Answer. A

Question. Which of the following is a disadvantage of file processing system?
a) Data redundancy
b) Data isolation
c) Data inconsistency
d) All of the above
Answer. D

Question. Degree refers to total_________
a) number of rows in a table
b) number of columns in a table
c) number of data items in a table
d) none of the above
Answer. B

Question. Answer the questions based on the table Employee. Table: Employee EMPID ENAME SALARY DEPTNO Email
1001   George    30000   10   George23@yahoo.co.in
1002   Mary      32000    12   Mary_123@yahoo.co.in
1003   Alwin     25000    12    Al_win@gmail.com
1004   Sumit    20000    11    Sumit_222@yahoo.co.in

Question. The cardinality of the table Employee is ……
i) 5
ii) 4
iii) 3
iv) 6
Answer. B

Question. The degree of the table Employee is …….
i) 3
ii) 4
iii) 5
iv) 6
Answer. C

Question. Which column can be made as the primary key in the table Employee?
i) EMPID
ii) EMAIL
iii) Both i and ii
iv) None of the above
Answer. C

Question. If two columns are added to the table Employee, then the cardinality and degree of the table is …… and …… respectively.
i) 4 , 7
ii) 7, 4
iii) 6,5
iv) 5,6
Answer. B

Question. State True/False: Both EMPID and EMAIL can be defined as primary key in the table Employee.
i) True
ii) False
Answer. B

Question. An attribute in a relation is a foreign key if it is the ________ key in any other relation.
a) Candidate
b) Primary
c) Super
d) Sub
Answer. B

Question. A(n) ________ in a table represents a logical relationship among a set of values.
a) Column
b) Key
c) Row
d) Attribute
Answer. C

Question. Which of the following attributes can be considered as a choice for the primary key?
a) Name
b) Street
c) RollNo
d) Subject
Answer. C

Question. Fill in the blanks

1.A ------------------ is a special control structure that facilitates the row by row processing of records in the resultset.
2.After importing mysqlconnector, first of all --------------is established by using connect()
3.-----------------method executes a database query from within Python.
4. Running of sql query through database cursor returns the table records in the form of---------------
5.A connectivity package---------------must be imported before running db connection program.
Answer. 1.database cursor  2.database connection.  3. execute()  4.resultset  5.mysql.connector

Very Short Answer Questions:

Question. What is primary key?
Answer. A primary key is a column or set of columns that contain values that uniquely identify each row in a table.

Question. What do you mean by candidate key?
Answer. It is an attribute or a set of attributes or keys participating for Primary Key, to uniquely identify each record in that table.

Question. What is meant by degree and cardinality of a table?
Answer. Degree refers to the number of attributes/columns in a relation. Cardinality refers to the number of tuples/rows in a relation

Question. What is meant by RDBMS?
Answer. RDBMS (relational database management system) is the software used to store, manage, query, and retrieve data stored in a relational database. The RDBMS provides an interface between users and applications and the database, as well as administrative functions for managing data storage, access and performance.

Please click on below link to download CBSE Class 12 Computer Science Sql Worksheet Set B