CBSE Guess > Papers > Important Questions > Class XII > 2011 > Computer Science > Computer Science By Mr. Kapil Bhatia
CBSE CLASS XII
Basic Theory (Part 2)
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- Name all the models available for database system.
Ans. There are three data models available:
a. Relational data model
b. Hierarchical data model
c. Network data model.
- What is e-mail? What are its advantages?
Ans. The e-mail or electronic mail is sending and receiving messages by a computer. The major advantages of e-mail are:
- easy record maintenance
- low cost
- fast delivery
- What do you mean by the backbone network?
Ans. A backbone network is a network that is used as a backbone to connect several LANs together to form a WAN. Example. FDDI (Fiber Distributed Data Interface)
- What do you mean by client / server architecture?
Ans. Client server architecture refers to a network in which a workstation can request information from a computer that can shares resources i.e. the server.
- What is a relation? What is the difference between a tuple and an attribute?
Ans. Relation is a table, which is an arrangement of data in row and column format. Each of the relation has a number of columns with unique names.The rows of the table are called tuples and the columns of the table are called attributes.
- Describe Usenet.
Ans. Usenet is a group of individuals sharing a particular interest to discuss views regarding their interest i.e. newsgroup.
- Differentiate between ifstream class and ofstream class.
Ans. Ifstream class is used to create stream objects from which the syntax receives input data. Ofstream is used to create stream object to which the system can output data.
The ifstream is derived from istream class and it is used to associate a file with and input buffer so that the file can be read from .
The ofstream is derived from ostream class and it is used to associate a file with and output buffer so that the file can be write onto.
- What do you understand by visibility modes in class derivations? What are these modes?
Ans. Each member function and data member of a class has an attributes known as its visibility. The visibility mode determines the availability of the members of a base class to the deriving class from the derives class. The three modes are private, public and protected.
- Differentiate between read( ) and write( ) function.
Ans. Function write( ) writes data to a binary file from buffer. read() function read data in the buffer from a binary file.
- What is bridge?
Ans. Bridge is used to connect two network of same type such as that the LANs are logically same but physically separate.
Submitted By Mr. Kapil Bhatia
Email Id : [email protected]
