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5. Consider the following table:
Emp No Emp Name Designation
1 Sahil A
2 Anup B
3 Mansi A
4 Pooja B
Using the above table answer the given questions:
● Identify the Primary key.
● EmpName has all the unique names. Can it work as a primary key? Justify your answer
Ans. Primary Key - EmpNo
No, Empname cannot work as a Primary key because presently it may have unique values but there are chances that a new
employee with the same name can join the company then the field will have duplicate values and so cannot be used as a
primary key.
6. Find out which of the following fields of table Bank can be selected as primary key, candidate key and alternate key?
Account No, Customer Name, Date of Birth, PAN Number, Opening Balance
Ans. Primary key - AccountNo
Candidate key - AccountNo and PAN Number
Alternate key - PAN Number
7. What are the disadvantages of DBMS?
Ans. ● Cost of Hardware and Software :Through the use of a database system, new costs are generated due to additional
hardware and software requirements.
● Complexity :A database system creates additional complexity and requirements.
● Database Failures: If the database is corrupted due to power failure or it is corrupted on the storage media, then our
valuable data may be lost or the system will stop working.
● Lower Efficiency :A database system is a multi-user software, which is less efficient.
21 st #Communication
C. Competency-based/Application-based questions: Century #Leadership & Responsibility
Skills
1. A restaurant wants to maintain the list of their customers in a RDBMS.
a. Suggest him a few RDBMS software.
b. Name a few columns that can be created for storing customer information.
c. Which column can be created as a Primary key?
d. What is another name for a row and a column in RDBMS?
Ans. a. Oracle, IBM DB2, Microsoft SQL Server, Microsoft Access, PostgreSQL, MySQL, FoxPro, and SQLite.
b. Few columns can be Customer Code, Customer Name, Address, Phone number, City
c. Customer code can be created as a Primary Key.
d. Another name for row is Tuple and for column is Attribute.
2. A teacher has created a list of students' details and marks in a database. She is not very familiar with the use of the
database. Help her in setting a few field properties and where are these field properties available:
a. Generate the roll numbers automatically.
b. The name field should have a maximum of 20 characters.
c. Marks should store value upto 1 decimal place.
d. Display the date of birth in dd-month-yyyy format.
e. Wanted to keep the place as default ‘Delhi’.
Ans. The field properties are available in the Design view of the table.
a. Autovalue
b. Length
c. Decimal Value
d. Format
e. Default
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