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The set difference operation, denoted by – (minus) allows us to find tuples that are in one relation but not in another. The expression A – B results in a relation containing those tuples in A but not in B. The set intersection operation finds tuples that are common to the two operands relations. The set intersection operation is denoted by ∩ . That means A ∩ B will yield a relation having tuples common to A and B. The difference between these two is that in set difference operation the result will contain those tuples which are in one operand but not in other.

Whereas in set intersection operation result will contain those tuples which are common in both the operands. 

It is a particular property, which describes the entity.

Ramachandra

“Priyadarshini”

2nd Block, Jayanagar

Bengaluru.

27 July 2019

The Editor 

The Hindu 

Bengaluru

Dear Sir,

Enclosed please find my views on the rash driving of vehicles in Bengaluru. I am of the opinion that there should be awareness programmes regarding this and as the first measure towards this I have put down my views. I request you to publish the same in your esteemed daily.

Thank you!

Yours faithfully, 

Ramachandra

An entity set may not have sufficient attributes to form a primary key, and its primary key compromises of its partial key and primary key of its parent entity, then it is said to be Weak Entity set.

1.  SELECT FirstName from EMPL WHERE Workdept NOT IN (‘Menufacture’);

2. SELECT EmpName, DeptName from EMPL WHERE Empno BETWEEN 100 and 300;

3. SELECT Empno, FirstName, Educlevel from EMPL WHERE Educlevel IN (16, 18, 20); 

1.   SELECT FirstName, LastName from EMPL;

2.  SELECT * from EMPL WHERE Workdept = “Menufacture”;

3.  Just give employee names in manufacturing systems.

The collections of entities of a particular entity type are grouped together into an entity set.

1. SELECT Empno, FirstName from EMPL WHERE Workdept = ‘Menufacture’ AND Jobcode = 54; 

2. SELECT Empno, FirstName from EMPL WHERE Workdept = ‘Menufacture’ AND Jobcode =< 15;

3. SELECT LastName, Salary+Bonus from EMPL WHERE Jobcode = (Educlevel * 3) AND ((Salary * 12) + Bonus) > 100000;

It is a collection of all entities of particular entity type in the database.

It is a collection (set) of entities that have same attributes.

This model is based on collection of objects. An object contains values stored in instance variables with in the object. An object also contains bodies of code that operate on the object. These bodies of code are called methods. Objects that contain same types of values and the same methods are grouped together into classes.

This data model is based on real world that consists of basic objects called entities and of relationship among these objects. Entities are described in a database by a set of attributes.

A collection of conceptual tools for describing data, data relationships data semantics and constraints.

A view may be thought of as a virtual table, that is, a table that does not really exist in its own right but is instead derived from one or more underlying base table. In other words, there is no stored file that direct represents the view instead a definition of view is stored in data dictionary.

Growth and restructuring of base tables is not reflected in views. Thus the view can insulate users from the effects of restructuring and growth in the database. Hence accounts for logical data independence.

1. b) burdened with responsibility 

2. d) (ii)(iii)&(iv)

3. c) He seems to be responsible carrying the steel canister. 

4. d) Only option (iv)

5. b) (i) rare; (ii) opportunities; (iii) Accepting; (iv) prove

Data independence means that "the application is independent of the storage structure and access strategy of data". In other words, The ability to modify the schema definition in one level should not affect the schema definition in the next higher level.

Two types of Data Independence:

1. Physical Data Independence: Modification in physical level should not affect the logical level. 

2. Logical Data Independence: Modification in logical level should affect the view level.

NOTE: Logical Data Independence is more difficult to achieve

1. c) (i) Innocent; (ii)foresight (iii)responsible; iv)caring 

2. d) (i)&(ii)

3. b) Going through an emotion which lacks happiness. 

4. c) He says he knows only bangle making and nothing else in his life. 

5. a) Curiosity 

a) Both A and R are true and R is the correct explanation of A. 

Unlike Relational systems in System R 

1. Domains are not supported 

2. Enforcement of candidate key uniqueness is optional 

3. Enforcement of entity integrity is optional 

4. Referential integrity is not enforced

1. c) Narrator wants Saheb to go to school instead of rag picking. 

2. d) There is no intention to build a school.

3. c) His name was opposite to his life. 

4. b) Is satisfied with watching the game standing by the fence of the club. 

5. d) All the above.

6. c) She thinks that her husband has gone blind due to his fate. 

7. c) He is strong in his decision of becoming a motor mechanic. 

8. d) All the above except (b)

System R was designed and developed over a period of 1974-79 at IBM San Jose Research Center. It is a prototype and its purpose was to demonstrate that it is possible to build a Relational System that can be used in a real life environment to solve real life problems, with performance at least comparable to that of existing system. 

Its two subsystems are:

1. Research Storage 

2. System Relational Data System.

Correct option is A) was going

Correct option is D) for

1. Extension: It is the number of tuples present in a table at any instance. This is time dependent. 

2. Intension: It is a constant value that gives the name, structure of table and the constraints laid on it.

A relation is a two-dimensional table. It contains number of rows (tuples) and columns (attributes). This is the horizontal part of the relation. One row represents one record of the relation. The rows of a relation are also called tuples.

A relation is a two-dimensional table. It contains number of rows (tuples) and columns (attributes). A relation has following properties :

(a). In any given column of the table, all items are of the same kind whereas items in different columns may not be of the same kind.

(b). For a row, each coloums must have an atomic value and also for a row, a columns cannot more than one value.

(c). All of a relations are distinct. That is, a relation does not contain two rows which are identical in every column. That is, each row of the relation can be uniquely identified by its contents.

(d). The ordering of two within a relation is immaterial. That is, we cannot retrieved any thing by saying that from row number 5, column name is to be accessed. Thee is no order maintained for rows inside a relation.

(e). The columns of a relation are assigned distinct names and the ordering of these columns is immaterial. 

Correct option is B) as tall as

There are generally three data models available as following : 

(i)  Relational Model

(ii) Network Model

(iii) Hierarchical Model

Among these three level relational level is the most preferred one because it does not use pointers or links. Instead, it relates records by the values they contain.

(i) Integrated database: Integrated database means union of several otherwise distinct data files, with any redundancy among those files partially or wholly eliminated.

(ii) Shared database: Sharing of data means that individual pieces of data in the database may be shared among several different users, in the sense that each of those users may have access to the same piece of data and each of them may use it for different purpose. The database which contains this type of data is called shared database.

(iii)  View: A view is a pseudo-table or virtual table. It displays the data. The data is derived from one or more base tables.

(iv) Database system:  A database is a collection of interrelated data and a database system is basically a computer base recordkeeping system.

(v) Data security:  Data security refers to protection of data against accidental or intentional disclosure to unauthorized persons, or unauthorized modification or destruction.

(vi) Data integrity:  Data integrity refers to maintaining and assuring the accuracy and consistency of data over its entire life cycle

Correct option is C) as tall as

There are two levels of data independence: Physical and Logical. Physical Data Independence modifies the scheme followed at the physical level without affecting the scheme followed at the conceptual level.

Whereas Logical Data Independence modifies the conceptual scheme without causing any changes in the schemes followed at view levels.

The network model and hierarchical model are similar in the sense that data and relationships among data are represented by records and links respectively. The difference between these two is that in network model records are organized as collection of arbitrary graphs and in hierarchical model records are organized as collection of trees.

A functional dependency occurs when one attribute in a relation uniquely determines another attribute. This can be written A -> B which would be the same as stating "B is functionally dependent upon A."

Examples:

In a table listing employee characteristics including Social Security Number (SSN) and name, it can be said that name is functionally dependent upon SSN (or SSN -> name) because an employee's name can be uniquely determined from their SSN. However, the reverse statement (name -> SSN) is not true because more than one employee can have the same name but different SSNs.

1. A polymer is a large molecule or a macromolecule which essentially is a combination of many subunits. The term polymer in Greek means ‘many parts’. Polymers can be found all around us. From the strand of our DNA which is a naturally occurring biopolymer to polypropylene which is used throughout the world as plastic.

Definition of a Prime Number: Any whole number greater than 1 that is divisible only by 1 and itself, is defined as a prime number.

Data type is an attribute associated with a piece of data that tells a computer system how to interpret its value. Understanding data types ensures that data is collected in the preferred format and the value of each property is as expected.

Data types in C Language 

Data types specify how we enter data into our programs and what type of data we enter. C language has some predefined set of data types to handle various kinds of data that we can use in our program. These datatypes have different storage capacities.

C language supports 2 different type of data types:

1. Primary data types:  

These are fundamental data types in C namely integer(int), floating point(float), character(char) and void.   

2. Derived data types:  Derived data types are nothing but primary datatypes but a little twisted or grouped together like array, stucture, union and pointer. These are discussed in details later.   

Data type determines the type of data a variable will hold. If a variable x is declared as int. it means x can hold only integer values. Every variable which is used in the program must be declared as what data-type it is.

Definition of a Prime Number: Any whole number greater than 1 that is divisible only by 1 and itself, is defined as a prime number.

The word Algorithm means “a process or set of rules to be followed in calculations or other problem-solving operations”. Therefore Algorithm refers to a set of rules/instructions that step-by-step define how a work is to be executed upon in order to get the expected results.

In other words,

Algorithm is a step by step procedure, which defines a set of instructions to be executed in certain order to get the desired output.
Algorithms are generally created independent of underlying languages.

Key features of algorithm

From data structure point of view, following are some important categories of algorithms −

• Search − Algorithm to search an item in a data-structure.

• Sort − Algorithm to sort items in certain order

• Insert − Algorithm to insert item in a data-structure

• Update − Algorithm to update an existing item in a data-structure

• Delete − Algorithm to delete an existing item from a data-structure

Basically structure of the C program is divided into six different sections,

1. Documentation section: The Documentation section consists of a set of comment lines.

2. Link section: The link section provides instruction to the compiler to link the header files or functions from the system library.

3. Definition section: The definition section defines all symbolic constants such by using the #define directive.

4. Global declaration section: There are some variables that are used in more than one function, such variables are called global variables.

In C there are two types of variable declaration,

Local variable declaration: Variables that are declared inside the main function.

Global variable declaration: Variables that are declared outside the main function.

5. Main function section: Every C-program should have one main() function.
This section contains two parts:

Declaration part

Executable part

6. Sub-program section: If the program is a multi-function program, then the subprogram section contains all user-defined functions that are called in the main() function.

The answer is : void

The step by step procedure to solve a problem is known as Algorithm.

A default constructor is the one that takes no argument. It is automatically invoked when an object is created without providing any initial values. In case, the programmer has not defined a default constructor, the compiler automatically generates it.

For example,

class A {...........};

A ob1;  // uses default constructor for creating ob1.

A parameterized constructor with default argument is equivalent to a default constructor.

For example,

class A { int i;

float j;

public:

A(int a = 0,float b = 1000.0); //constructor with default argument };

A::A(int a,float b) //constructor definition

{ i = a; j = b;

}

int main()

{

A o1(23,27.50); // argument value passed for o

 A o2; // takes default argument to o2(0,1000.0)

}

#include

class code

{

int no;

char branch;

static int count;

public:

code(int i=0,char b);

code(code &A)

{  

no=A.no;

branch=A.branch;

}

~code()

{

//count=0;

cout<<"Destroying Object"<<--count<<"\n";

}

};

int code::count=0;

code::code(int i,char b)

{ no = i;

branch = b;

}

int main()

{  code X,Y;

return 0;

}

Changes being introduced are as following:

i. Constructor definition should be public so that it can be accessed outside the class.

ii. There should be a use of ‘&’ operator in copy constructor.

iii. There should be a definition of the static variable outside the class definition.

iv. There is a invalid use of ‘:’ expression.

Constructor functions are invoked automatically when the objects are created.

No return type can be specified for a constructor.

A constructor may not be static.

They cannot be inherited, though a derived class can call the base class constructor.

It is not possible to take the address of a constructors.

The default constructor initializes the object X1 as constructor is invoked as soon as the object is created.

A constructor that accepts parameters for its invocation is known as parameterized constructor. This helps you to assign initial value to an object at the time of its creation. For example,

class Test {

int ant; 

public:

Test(int i) // constructor with argument

{ ant = i;

}

 };

int main()

{ 

Test ob1(45); //argument value provided

}

}

(i) Interview obj1(3);

(ii) Interview(Interview &t)

{  Month=t.Month;  }

The copy constructor is a constructor which creates an object by initializing it with an object of the same class, which has been created previously. The copy constructor is used to: Initialize one object from another of the same type. Copy an object to pass it as an argument to a function. Copy an object to return it from a function.

#include<iostream.h>

#include<conio.h>

class Example

{

int a,b;

 public:

 Example(int x,int y){ //Constructor with Argument

 a=x;

 b=y;

 cout<<"\nParameterized Constructor";

 }

 void Display(){

 cout<<"\nValues :"<<a<<"\t"<<b;

 }

};

void main ()

{

Example Object(10,20);

Example Object2 = Object; //Copy Constructor Object.Display(); // Constructor invoked. Object2.Display();

getch();

}