Computer Knowledge: Architecture of DBMS, Advantages and Disadvantages of DBMS for Competitive Exams

Architecture of DBMS 

The architecture of a database system provides a general framework for database system. This means that the system does not provide all the details of the data, rather it hides the details of how the data are stored and maintained.

The Architecture is divided into three levels;

1) Physical Level: It is the lowest level of data abstraction that deals with the physical representation of the database on the computer. It is also known as internal level. It defines how the data are actually stored and organised on the storage medium.

2) Logical Level: It is the overall view of the database and includes all the information that is going to be represented in the database. It describes what type of data is stored in the database, the relationship among the data without effecting to the physical level. It is also known as conceptual level.

3) View Level: This is the highest level of data abstraction which describes the interaction between the user and the system. It permits the users to access data in a way that is customised according to their needs, so that the same data cab be seen by different users in different ways, at the same time.

Advantages of DBMS 

1) Reduction in Data Redundancy: The duplication of data refers to data redundancy. DBMS cannot make separate copies of the same data. All the data is kept at a place and different applications refers to data from centrally controlled system.

2) Better Interaction with Users: In DBMS, the availability of up-to-data information improves the data to be access or respond as per user requests.

3) Improvement in Data Security: DBMS can allow the means of access to the database through the authorised channels. To ensure security, DBMS provides security tools i.e., username and password.

4) Maintenance of Data Integrity: Data integrity ensures that the data of database is accurate. In DBMS, data is centralised and used by many users at a time, it is essential to enforce integrity controls.

5) Backup and Recovery: The DBMS supports backup and recovery subsystem that is responsible to recovery data from hardware, software, virus attack and other failures.


Disadvantages of DBMS 

1) Complexity: The provision of the functionality that is expected from a good DBMS makes the DBMS an extremely complex piece of software. Failure to understand the system can lead to bad design decision, which can have serious consequences for an organisation.

2) Cost of Staff Training: Mostly DBMS are often complex systems so the training for user to use the database is required. The organisation has to pay a lot of amount for the training of staff to run the DBMS.

3) Database Failures: In most of the organisations, all data is integrated into a single database. If database is corrupted due to power failure or it is corrupted on the storage media, then our valuable data may be lost or whole system stops.

4) Cost of Maintenance: We need a high speed processor for processing large size of DBMS software. Similarly database software is also very costly. It means we must upgrade the hardware used for database management.

Mathematics: Tips for Solving Simple Equations Problems in Competitive Exams

Tips for Solving Simple Equations Problems 

An equation is a statement where the two sides are equal. In other words, equations are combinations of one or more letters/numbers lying on each side of an "equal to" (=) sign. They are valid or true for certain values of the letters only. The letters in the equation are called the unknowns.

For Example: What number multiplied by 6 gives a product of 18 ?

You may calculate with the help of tables and find out the answer as 3. (you can recall the table of 6 or you can divide 18 by 6 to find out the answer). However, there is another method of finding out that number.

Suppose the number is X.

6 x X = 18 (given in the question)

6X = 18 => X = 18/6

                    X = 3.

Equation are Classified into:

• Polynomial Equations: If f(x) is real or complex polynomial, then f(x) =0 is known as a polynomial equation. 

• Linear Equations in One Variable: These are first degree equations in one unknown. An equation of the form ax + b = 0 where a, b subset of R and a not equal to zero and x is the variable, is called a linear equation in one variable. The value of x which satisfies the given equation, is called its solution.

• Linear Equation in Two Variables: These are first degree equation in two unknowns. An equation of the form ax + by + c = 0, where a, b, c subset of R and a not equal to 0, b not equal to 0 and x, y are variables is called linear equation in two variables. Any pair of values of x and y which satisfy the equation ax + by + c = 0, is called its solution.

• Quadratic Equation: These are second degree equations in one unknown. An equation of the form ax² + bx + c = 0, where a, b, c subset of R and a not equal to 0 is called quadratic equation. Like a first degree equation in x has one value of x satisfying the equation, a quadratic equation in x will have two values of x that satisfy the equation. The value of x that satisfy the equation are called the root of the equation. These roots may be real or imaginary.

Important Points to Remember:

• You can add to or subtract any number or quantity from each side of an equation without upsetting the balance.
• You can multiply or divide both sides of an equation by the same number without upsetting the balance.
• You can transfer any number or quantity from one side of the equation to the other if you change its sign ( + to - ) or ( - to +) when you do so.

Sample Problems:

1) What is the number which, when added to 6, become 15 ?

Sol:-

    You may just count and calculate and find out the answer as 9 (15 - 6 = 9).

     Better you solve the question with the help of an equation.

              Suppose the number is X.

There fore X + 6 = 15.

        Now X = 15 - 6.  = 9

                X = 9.

 

2) Find Y, if ½(3Y = 1) - 1/3(5Y + 2) = Y -1

Sol:-

          ½(3Y + 1) - 1/3(5Y + 2) = Y-1

=> (9Y + 3) - (10Y + 4) = 6Y - 6

=> -Y -1 = 6Y - 6

=> 7Y = 5

=> Y = 5/7

Mathematics: Tips for Solving Direction Sense Problem for Competitive Exams

Tips for Solving Direction Sense Problem

The questions asked from this chapter are based on direction and distance both. In this type of questions, students have to find out the direction or distance, which is covered from the starting point (position) to certain ending point(position). That means students are required to ascertain the final direction or the distance between two points. These questions are asked to test the candidate's ability to trace and follow correctly and sense the direction correctly.

Students are advised to pin-point on a piece of paper the starting-point. Then they should draw lines as directed (indirected) in the question. Thus they will have a diagram (figure) of the movement. It will thus the easy to find direction from the starting point.

According to the above diagram, we can easily understand about the directions. To find out the lowest distance between two points, we use Pythagoras theorem. Direction between North and West is called North-West, the direction between North and East is called North-West similarly we know the South-West and South-East.

If we are walking towards any direction and we have to turn right, then we should turn right or in clock wise direction with 90°. If we have to turn left, then we should turn anti-clockwise direction at 90°.

Sample Problem

1) Ramesh starts from his house and goes to the east. After covering 4 km, he turns to right and covers 2 km. Then he turns to right again and covers 4 km. In which direction now Ramesh is from his house ?

Solution: 

                         Ramesh's house       4 km

                                          ------------------------------┐

                                                                                │2 km

                                                                                │

                                          -------------------------------

                                                      4 km 

The above diagram indicates that he is now in the south from his house.

Marketing Knowledge: Marketing mix and Elements of Marketing Mix for IBPS, SBI and other Competitive Exams

Marketing Mix and Elements in Marketing Mix

Marketing Mix:

Marketing mix is an important concept in modern marketing. It is the crux of marketing process. It refers to the set of actions or tactics, that a company uses to promote its brand or product in the market. It includes almost everything that a firm uses to affect consumer's perceptions favourably towards its products or services, so that the consumer and organisational objectives can be achieved.

However, the 4 P's remain the most popular classification in terms of marketing mix. In 1990, Robert F Lauterborn proposed a 4 C's classification, which is a more consumer-oriented version of the 4 P's.

Elements of Marketing Mix:

The elements or components of marketing mix may be grouped broadly under the following four heads.

• 1) Product
• 2) Price
• 3) Place
• 4) Promotion

1) Product: 

Product refers to the goods and services offered by the organisation for sale to the consumer for a price. In other words, a product is a bundle of utilities consisting of various features and accompanying services.

Product can be broadly classified as follows:

Based on Use, the products can be classified as

i) Consumer Goods: Products that are purchased for personal consumption by the households or ultimate consumers are known as "Consumer Goods". Dresses, auto-mobiles, food, Gold or other jewellery item are all examples of consumer goods. These consumer goods are classified into 3 parts they are

• Convenience Goods
• Shopping Goods
• Speciality Goods

ii) Industrial Goods: These goods are meant for use as inputs in production of other products or provision of some service and include raw materials, machinery, components and operating supplies. These are meant for non-personal and commercial use.

2) Price: 

It is the amount charged for a product or services. In other words, price is the consideration in terms of money paid by consumers for the bundle of benefits, he derives by using the product or service. It is the exchange value of goods and services in terms of money. Price is the only element in the marketing mix of a firm that generates revenue. Rest of them generate only cost. Price and volume of sales together decide the revenue of any business. Various factors that have to be kept in mind while fixing the price are demand for a product, cost involved, consumer's ability to pay, prices charged by competitors for similar products, government restrictions, etc.

3) Place: 

Goods and services are produced to be sold to the consumers. They must be made available to the consumers at a place where they can conveniently make purchase. Place is concerned with various methods of transporting and storing goods and then making available for the customer.Getting the right product, to the right place, at the right time, involves the distributions system and the choice of distribution method depends on a variety of circumstances. Making the products available, it involves a chain of individuals and institutions like distributors, wholesalers and retailers who constitute company's distribution network.

4) Promotion: 

Promotion is an important thing in marketing mix as it refers to a process of advertising, influencing a consumer to make select the product of the company is a big question. Promotion is done through selling, advertising, publicity and sales promotion. It is done mainly with a view to provide information to consumers about the quality, durability, availability and use's of the product.

General Studies: Geography Topic Wind System for Competitive Exams

Wind System

The pressure difference is the major causes of the genesis of the wind system. The air moves from high pressure to low pressure. The slope of pressure from high to low is called pressure gradient, which is also called as barometric slope. The imaginary line joining the points having same pressure is called isobars. The direction of air movement should be perpendicular to the isobars because the direction of pressure gradient is perpendicular to the isobars, but the direction is deviated from the expected one due to Coriolis force caused by the rotation of the Earth.

Thus the factors that control the air motion are

• Pressure gradient
• Rotation of Earth and Coriolis force
• Friction force
• Centrifugal action of wind

The winds blowing parallel to the isobars generally at the height of 600 meters is called Geo-strophic wind.

Wind Directions

The Coriolis force generated due to the rotation of Earth acts as a deflective force to the wind direction. Because of the Coriolis force, all the winds are deflected to the left in the Southern hemisphere with respect to the rotating Earth.This is referred to as Farrel's Law. The Coriolis force is absent along the equator, but increases progressively towards the poles.

Classification of Winds:

Winds are classified into Three types by the direction of wind system, They are

• 1) Primary Movement:  Permanent Winds
• 2) Secondary Movement : These are classified into Three types

                ( i ) Cyclone : Tropical and Temperate, Thunderstorms and Tornadoes

                ( ii ) Anti Cyclone

                ( iii ) Seasonal Wind i.e., Monsoon

• 3) Tertiary Movement: Local Winds

1) Primary Wind Movement:

These winds are include trade wind, westerlies and polar winds.

i) Trade Wind: These are steady currents of air blowing form the sub tropical high pressure belt towards the equatorial low pressure belt. Under the influence of the Coriolis forces they flow from the North-East in the Northeren hemisphere and from South-East in the Southern hemisphere.

ii) Westerlies: The permanent winds blowing from the subtropical high pressure belt to the sub polar low pressure belt in both the hemisphere is called Westerlies. The general direction of the westerlies is South-West to North-West in the Northern hemisphere and North-West to South-East in the Southern hemisphere. The Westerlies become more rigorous in the Southern hemisphere because of the lack of land and dominance of oceans. Their velocity increases Sothward and they become stormy so they are called roaring forties between latitudes 40°. South latitudes, furious fifties at 50° South latitude and shrieking sixties at 60° South latitudes.

iii) Polar Winds: Polar winds blows from polar high pressure belt to sub-polar low pressure belt. They are North-Easterly in Northern hemisphere and South-Easterly in the Southern hemisphere.

2) Secondary Wind Movement: 

Seasonal Winds: The winds, which reverse its direction completely every 6 months is called Seasonal Winds. The best example is Monsoon winds.

i ) Cyclone: Cyclones are the centres of low pressure surrounded by closed isobars having increasing pressure outward and closed air circulation from outside towards the central low pressure in such a way that Air blows inwards in clockwise direction in the Southern hemisphere. Air blows inwards in clockwise direction in the Southern hemisphere.

Cyclones are mainly of two types;

• Tropical Cyclone
• Temperate Cyclone

ii ) Anticyclone: They are the wind system, which has the highest air pressure at the centre and lowest at the outer margins surrounded by circular isobars where wind blows. They are high pressure system and common in subtropical belts and practically absent in the equator region. They are generally associated with rainless fair weather and that's why they are called as weather less phenomena. 

3) Tertiary Movement 

Tertiary Movement is also called Local Winds. Some local winds are mentioned in the below table

Tertiary Movement (Local Winds)
Wind	Nature	Region
Land Breeze	Warm	Land breeze blows from land to sea
Sea Breeze	Cold	Sea breeze blows from sea to land
Chinook (snow eater)	Warm	Rockies (USA and Canada)
Sirocco	Hot	North Africa
Fohn	Warm	Alps/Europe
Khamsin	Hot	Egypt
Blizzard	Cold	Siberian, Canada, USA

General Studies: Indian Economy topic Poverty in India for Competitive Exams

Poverty in India

Poverty is a social phenomenon where in section of society is unable to fulfil even its basic necessities of life. Planning Commission is the authority, which publishes the poverty estimates based on various rounds of National Sample Survey Organisation (NSSO) on monthly per capital consumption expenditure. In India, the poverty line is defined on the basis of calorie intake. According to this, 2100 calories a day has been fixed for urban areas and 2400 calories in rural areas.

Alternatively, in monthly per capita consumption expenditure terms, the poverty line is fixed at Rs. 454.0 for rural areas and Rs. 540.0 for urban areas. Based on the definition poverty line given above the percentage of people below poverty line (or poverty ratio) is provided in the table.

Since, NSSO 55th Round(1999) Planning Commission gives two poverty estimates based on Mixed Recall Period (MRP) and Universal Recall Period (URP). Mixed Recall Period, gives consumer expenditure data for five non-food items, goods, education and institutional medical expenses for 365 days and consumption data for remaining items are collected for 30 days period. Universal Recall Period, consumption data for all items  are collected for a 30 days recall period.

Causes for Rural Poverty:

• ( i ) Rapid Population growth
• ( ii ) Lack of capital
• ( iii ) Lack of alternate employment opportunities other than aggriculture
• ( iv ) Excessive population pressure on agriculture
• ( v ) Illiteracy
• ( vi ) Regional disparities
• ( vii ) Joint family system
• ( viii ) Child marriage
• ( ix ) Lack of proper implementation of PDS (Public Distribution System)

Causes for Urban Poverty:

• ( i )  Migration from rural areas
• ( ii ) Lack of skilled labour
• ( iii ) Lack of housing facilities
• ( iv ) Limited job opportunities in cities
• ( v ) Lack of vocational education or training

Estimation of Poverty by Finance Commission:

The Seventh Finance Commission attempt to inclusive concept of poverty line. Since the NSS data cover only household Consumer expenditure. thus, to get a more inclusive measure of welfare or deprivation, an estimate of the benefit of public expenditure was added to Private Consumer Expenditure norm for calculating the augmented poverty line.

Computer Knowledge: Database Concepts and Its Components for Competitive Exams

Database Concepts

A database is a collection of logically related information n an organised way so that it can be easily accessed, Managed and updated. Some other operations can also be performed on database such as adding, updating and deleting data. A database could be simple as a single text file with a list of names or it could be complex as a large bunch of text files including some data.

In database, data can be entered through input devices such as keyboard, mouse, touch-screen, etc. Some examples of database are telephone directory, railway timetable, books catalogue, equipment inventory, etc,.

Fundamentals of Database:

For defining database, two terms, which are used frequently with database, should be known.

Data: These are raw and unorganised facts that need to processed such as digital representation of text, numbers, graphical images or sound. Data refer to the values physically recorded in the database e.g., a student's text score is one piece of data.

Information: When data is organised, processed, presented or structured in given context to make it useful or meaningful, it is called information. Information refers to the conclusion or meaning drawn out of it. e.g., the class's average score is the information that can be concluded from the given data.



Types of Database

Database are of three types, namely

1) Network Database: In this type of database, data is represented as collection of records and relationships among data are represented as links.

2) Hierarchical Database: In this type of database, data is organised in the form of trees with nodes. Nodes are connected via links.

3) Relational Database: Relational database is also known as structured database in which data is stored in the form of tables. Where, columns defines the type of data stored in the table and rows defines the information about the data.

Components of a Database:

A database consists of several different components. Each component listed, these are  called an object. In one single file, you can divide your data into separate storage parts (Containers) called tables. View, add and update table data by using query's or on-line command forms. find and retrieve the data you want by using queries and analyse or print data in a specific layout by using reports.

Database components are described below;

Tables: Tables are the building blocks or relation of any relational database model where all the actual data is defined and entered. Tables consists of cells at the intersection of records (rows) and fields (columns). Different type of operations are done on the tables such as storing, filtering, retrieving and editing of data.

Field: A field is an area (within the record) reserved for a specific piece of data. e.g., student number, student name, address, city, state, phone number, current address etc., Field of a table is also known as column.

Record: A record is the collection of data items of all the fields pertaining to on entity i.e., a person. company, transition etc. Record of a table is also known as row or a tuple and the number of records in a relation is called the cardinality of that relation.

Queries: Queries are basically questions based on the data available in a database. A query consists of specifications indicating which fields, records and summaries a user want to fetch from a database. Queries allow you to extract data based on the criteria you define.

Forms: Although you can enter and modify data in datasheet view of tables but you neither control the user's action very well nor you can do much to facilitate the data-entry process. To overcome this problem, forms are introduced.

Reports: When you want to print those records which are fetched from your database, design a report. Access even has a wizard to help produce mailing labels.