Page 124 - IPP-12-2025

43. What is meant by Topology? Name some popular Topologies.
Ans. Topology is the arrangement by which computers are connected to each other, either physically or
logically. The popular topologies are:
(i) Bus or Linear Topology (ii) Ring Topology
(iii) Star Topology (iv) Tree Topology
44. Which of the network topologies should be preferred for a company that would like to keep adding
economically more and more computers to the topology as it grows?
Ans. Tree/Star
45. What is TCP/IP?
Ans. TCP/IP (Transmission Control Protocol/Internet Protocol) is a protocol for communication between
computers used as a standard for transmitting data over networks and is the basis for standard internet
protocols. It is also responsible for assembling packets at the receiver’s side.
46. Define the following data communicating devices:
(i) Repeater (ii) Bridge
(iii) Router (iv) Gateway
Ans. (i) Repeater: It is a device that amplifies and restores the signal before it gets degraded and transmits the
original signal back to the destination. A repeater is a regenerator and not an amplifier.
(ii) Bridge: A bridge is a device designed to connect two LAN segments. The purpose of a bridge is to filter
traffic on a LAN. Bridge relays frames between two originally separate segments. When a frame
enters a bridge, the bridge not only regenerates the signal but also checks the physical address of the
destination and forwards the new copy only to that port.
(iii) Router: Routers operate in the physical, data link and network layers of the OSI model. They decide the
path a packet should take. A router is a networking device whose software and hardware are usually
tailored to the tasks of routing and forwarding data packets across the network.
(iv) Gateway: A gateway operates on all the seven layers of OSI model. A network gateway is a computer
which has internet-working capability of joining together two networks that use different base protocols.
Gateway converts one protocol to another and can, therefore, connect two dissimilar networks.
47. What is RDBMS?
Ans. Relational Database Management System (RDBMS) facilitates access, security and integrity of data and
eliminates data redundancy. For example, MySQL, Oracle, Microsoft SQL Server, etc.
48. What is MySQL?
Ans. MySQL is an open-source RDBMS that relies on SQL for processing data in the database. The database is
available for free under the terms of General Public License (GPL).
49. What is Primary key?
Ans. Primary key is a combination of columns that uniquely identifies a row in a table.
50. What is Candidate key?
Ans. All possible combinations of columns that can possibly serve as the primary key or any other column are
called candidate keys.
51. What is Alternate key?
Ans. A candidate key that is not serving as a primary key is called an alternate key.
52. What is Foreign key?
Ans. A combination of columns where values are derived from primary key or any other column of some other
table is called the foreign key of the table in which it is contained.
53. What is the use of DROP TABLE command?
Ans. DROP TABLE command is used to delete tables. For example, DROP TABLE Orders; will delete the table
named ‘Orders’.
54. What do you understand by NOT NULL constraint?
Ans. This constraint ensures that the NULL values are not permitted on a specified column. This constraint can
be defined at the column level and not at the table level.
55. What is the significance of count()?
Ans. It is used to count the number of values in a given column or number of rows in a table; for example,
SELECT COUNT(RollNo) FROM Students;

V.4 Informatics Practices with Python–XII