Fundamentals of computer science tutorial (FCST)

Important MCQ of RDBMS  1. A RDBMS consists a collection of ? a. Tables b. Fields c. Records d. Keys  ANS/- a. table 2. The term attribute refers to a ___________ of a table a. Record b. Tuple c. Column d. Key   ans/- c. Column 3. In relational model, the row of table is known to be ?  a. Relation b. Entity field c. Tuple d. Attribute  ans/- C. Tuple 4. . Address field of a person should not be part of primary key, since it is likely to ? a. Dependent b. Too long c. Changed d. Not changed  ans/- c. Changed 5. The relational model is concerned with ? a. Data structure and Data integrity b. Data Manipulation c. Both a and b d. None of these  ans/- c. Both a and b 6. Which is the false statement from the following ? a. A veiw is a named derived table b. A name relation is variable c. A veiw is a named reation and is virtual d. None of these  ans/- d. None of these 7. The union of primary keys of the related entity sets becomes a

 Intro of computer network and needs of OSI model A computer network is a collection of various computing devices. The purpose of computer networks is to enable the devices to share the data. Means, to connect the various devices - various heterogeneous and homogeneous devices. The main purpose of computer networks is to share the data. Now, in computer networks, we have one sender and one receiver. Sender is the one who is trying to send some data to the receiver. The sender and receiver can be a machine. The user sends the data through a machine. So we can say, the sender writes a program to send some data to the receiver. Now, how will the user send the data? It requires some kind of a connection. Connection can be a wired connection or a wireless connection. But first of all the user needs some connection. Through the connection, the packets or the data will move from the sender machine to the receiver machine. Now, the term over there is connection. Next is, the sender has

  Definition of File system  &  it's advantage of DBMS over file system What is file system? Ans/- A file system is a database system that allows us access to single file at a time. In a file system data is directly stored in set of file. It contains flat file that have no relation to other file. Advantage of DBMS over file system :-       1)       Data redundancy : - Data redundancy refers to the duplication of data that means each data may have a single copy. A file system can’t control redundancy of data. In DBMS data redundancy removed by using of data normalization.        2)    Data inconsistency : - Data redundancy leads to data inconsistency. In DBMS data redundancy is taken care by data normalization and data in consistency also been taken care of as part of it.        3)     Data isolation : - In file system data stored are in various file and files may be different formats. So it is very difficult to retrieved appropriate data. But DBMS data sto

C program to find factorial of number using function Problem description In this program take number as input & then it show the factorial of given number as output. Problem solution 1.take a number as input. 2.declare the void Fact(int) function globally if you want or declare the function prototype  into the main() function. 3.after taking input call the function into main() . 4.then define the function definition. 5.after taking function definition for loop started in this function definition. 6. In for loop i=1 & fact=1 then fact=1. after this loop is continue and incremented by1 until the n is grater than equal to i. continuity of loop is depend on what number take as input .  Program code: #include<stdio.h> void Fact(int);//function prototype declearation int i,fact=1;//global variable declearation int main()  { int n; printf("\n enter the  number:"); scanf("%d",&n); Fact(n);//function call } //function

            Database Schema &  Data Independence PDF version of this post also available. to download the click the link given at the end of this post.           Database Schema : -  A database schema   is the skeleton structure that represents the logical view of the entire database. It defines how the data is organized and how relat ion among them are associated.  Database schema  formulates all the constrains that are to be applied on the data. A database schema defines its entities and the relationship among them. It contains descriptive details of the database which can be described by means of schema diagram. A database schema can be divided into two categories.   I.     Physical database schema : - this schema contain to the actual storage of data and its form of storage like files, indices etc. It defines how the data will be stored in a secondary storage.   II.   Logical database schema : - this schema defines all the logical constrains that need to be appli

    Relation model concept and it's advantage & disadvantage     PDF version of this post also available. to get the pdf click the link given at  the    end of this post.            1. What is relational model?     Ø Relation model represent database as a collection of relations. A relation is nothing but a table of values. Every row in the table represents a collection of related data values. This row in the table denotes a real world entity or relationship.       Relational model concept : -   · Attribute : - Each column in a table, Attributes is the properties which define a relation.  Example: - DNO, DNAME.   · Table : - In the relational model relations are saved in the table format. A table has two properties rows, column. Rows represent records and column represents attributes.   ·   Degree : - The total number of attribute which in the relation which called the degree of relation.   · Cardinality : - Total number of rows present in the ta

  Entity set & it's types PDF version of this post also available. to download the click the link is given at the end of this post.   1. What is entity? Ans/-  An  entity  can be a real word object either animated or inanimate that can be easily identifiable. An entity in a database is represented as a set of attributes. Each entity has a different  sets of values for some set of attributes and this is how entity seems to be distinct from other entities.  In relational model , an entity is represented as a row, tuple or a record. 2. What is Entity set? Ans/- An  entity set  is a group of similar kind of  entities.  It may contain  entities  with attributes sharing similar values. Entities are represents by their properties which also called attributes. Type of entity : - Entities    are two types. there are  a) weak entity b) strong entity. now we explain these entities with example and also their difference between them.   Weak entity : -  A weak en

Relational Database Management System languages and their commands Database languages play an important role in Relational database management system. Database languages  are used to read, update and store data in database. These  database languages  that can be used for this purpose one of them  SQL . Types of Database languages There are five types of database language DDL: -D ata  D efinition  L anguage DML: -D ata  M anipulation  L anguage DCL: -D ata  C ontrol  L anguage SQL: -S tructure  Q uerying  L anguage TCL : - T ransaction  C ontrol  L anguage          1) DDL(Data Definition Language) :-   D ata  D efinition  L anguage used for  specifying the data base ‘schema’ . It is used for creating tables, schemas etc. in database. Commands of  D ata  D efinition L anguage( DDL ) are given below CREATE: -  to create database instances. This commands use  to create tables as follows:-          CRATE TABLE [name of table] ([definition of column]) [parameter

  Hashed Files l   Hashing for disk files is called  External Hashing l    The file blocks are divided into M equal-sized  buckets , numbered bucket 0 , bucket 1 , ..., bucket  M-1 . Typically, a bucket corresponds to one (or a fixed number of) disk block. l    One of the file fields is designated to be the hash key of the file. l    The record with hash key value K is stored in bucket i, where i=h(K), and h is the  hashing function . l    Search is very efficient on the hash key. l    Collisions occur when a new record hashes to a bucket that is already full. An overflow file is kept for storing such records. Overflow records that hash to each bucket can be linked together. There are numerous methods for collision resolution, including the following: l    Open addressing:  Proceeding from the occupied position specified by the hash address, the program checks the subsequent positions in order until an unused (empty) position is found. l    Chaining: