WEB TECHNOLOGIES

What is web ?

Web is a system of hypertext documents interlinked to each other.

Why is this Web required ?

The websites which we visit, e.g. facebook, wikipedia and many more, are accessed using Web. It makes information available anywhere in the World.

How do we use Web ?

• Each and every resource present on the Web, which we also call as Web-pages, is given an unique and identifiable address called as URL( Uniform Resource Locator).
• In-order to visit these web-pages, we need Web Browsers (e.g. google chrome, Internet explorer, mozilla-firefox, Opera, Safari ), where we write URL of the required web-page which we want to visit in the address bar of the Web Browser.
• Internet connection is required to carry this request(request for web-page) to the Web and bring response( Web-pages ) from the Web back to user.

Web-page request and response

Web- History and Evolution

In year 1989, Sir Tim Berners-Lee ( who is also known as the father of the WWW( World Wide Web) ) elaborated an IMS (Information Management System) that he built in 1980 which he named 'ENQUIRE' and  wrote a proposal based on it.

In the year 1990, He wrote a more formal proposal to build a Hypertext Project called 'WWW i.e World Wide Web'. In this year Lee used a computer named 'NEXT' as a world's first web server.

Tim Berners Lee with his world's first web server(NEXT)

World's first Web Server (NEXT)

       

• In the same year i.e. 1990, he also wrote world's first web browser.
• In the year 1991, the WWW ( World Wide Web ) was made available to public.
• In the year 1993, the CERN announced WWW ( World Wide Web ) free to all without any kind fees. This year was the beginning of the era of Web 1.0
• The year 2003, with considerable modifications Web 2.0 launched.

SOFTWARE ENGINEERING

Coming Soon.........

JAVA

Coming soon.......

RELATIONAL DATABASE MANAGEMENT SYSTEMS

What is a database ?

A database is an organized collection of interrelated data. 

Data has always been an useful entity, and when it becomes huge, then it becomes an urgency to store it somewhere, so that it can be referred or retrieved whenever required at some later point of time.

In early ages, our predecessors carved on stones for the sake of records, then after the invention of paper, the information was started to be written on paper.

Now in the age of science and technology, we have developed such electronic gadgets, where the procedures of storing data are just a touch away.

So, the proper formatted organization of large amount of data, which we store in memory devices, is referred to as DATABASE.

e.g.

• Banks have to store a huge amount data about its customers and their accounts. So, the data about their Customers is an example of database.
• Airlines ticketing services has store data about its passengers and their bookings. So that data about passengers is an example of database.
• All the email-id providers have to store huge amount of data of their users.So the data of those users forms the database.
• Universities have to store information about their students and their corresponding courses etc. So, all the info related to the students forms the database.
• All the countries keeps the record of its citizens, which also forms the perfect example of database.

What is a Database Management System ?

Database Management System is a set of programs ( i.e. a software ), which helps the user to store and manage data in a very organized way as per the requirements.

Let's say we run a showroom, and we want to store data about every that customer who visits our store, so that we can get to know about our customer base and moreover we can inform customers of special discounts and offers by retrieving their contact numbers from our Customer table stored in the database.

 So, DBMS(i.e. Database Management Systems) help us in creating databases.

A database so created may consists of so many tables, relationships among those tables, indexes, views etc.

Here in the above Scenario, we would like to create a table named Customer, which goes into the database, and then populate that table with the values of customers who visits our store.

The table so created would further consists of attributes, say : name_of_customer, Address, Contact_no, No_of_visits, email_id  etc.

we will insert values of all the customers who visits our store corresponding to the attributes present in the customer table.

  

            Conclusively, DBMS is a software (there are many such DBMS softwares available on the internet, that can be downloaded, such as Oracle database 11g, MySql, Microsoft Sql Server etc. ), which we use to create( using SQL(Structured Query Language)  coding ) databases as per our requirements.

In short, a DBMS allows us to perform :

• Reading operation
• Insertion operation (i.e. inserting values into the tables)
• Modification operation (i.e. changing values or table structures at some later point of time)

OPERATING SYSTEMS

What is an Operating System ?

If we speak in general terms, SOFTWARE is divided into 2 categories:

1. Application software
2. System software

Application Software

All the softwares which have specific functionality and which are little less complex than System Softwares, moreover they depend on System Softwares for their functioning and some of us use them in our daily lives, those are known as Application Softwares.

All the parts of above definition are very general and are written to make even a layman understand. 

e.g. of 

1) Softwares having specific functionalities are:

• Adobe photoshop(functions to work on pictures)
• MS Word (functions as a writing editor)
• Adobe Dreamweaver (functions as a website development tool)
• Oracle database 11g (functions as a database management tool)

2) Although they are also complex softwares, but as compared to System Softwares(windows 7,vista, 8, Machintosh), they are little less complex.

3)If windows is not installed on your laptop/desktop, then, Is it possible to run any of the above stated Application Softwares on your laptop/desktop. This implies Application Softwares are dependent on System Softwares for their working. They can't run on bare hardware.

System Software

Our laptop/Desktop consists of electronic parts, which we can see inside it's casing.We know that most of those electronic parts work on binary language (i.e. language of 0's and 1's ).

Operating system logos of various companies

Imagine if we've to directly work on hardware parts to get our work done, then we would have to remember large number of sequences of 0's and 1's, which is impossible. Therefore, we designed such softwares that deals with hardware behind the scenes and deals with us face to face, to get our work done.

So, the windows 7 , vista, xp, or 8 or machintosh( on apple laptops) which operates on hardware and interacts with us simultaneously , are called as System Softwares or OPERATING SYSTEMS.

NOTE : since the usage of WINDOWS is so much that, it has become synonymous to OPERATING SYSTEM.

Oracle database 11g release 2 installation problem on windows 7 (64-bit)

                   First of all my windows is not genuine, but on my friend's desktop oracle download and installation  worked fine, he chose "create and configure database" options, and it works very well on his desktop, though his windows is also illegitimate. In my case, when I select "Create and configure database" option and pressed 'next",

This is a snapshot from my laptop, which shows the initiation the installation process

Don't write email address here and uncheck for my support, just bypass this step

it asks to select class, I select "Desktop class" and pressed "next". The moment I pressed "next", the whole setup thing disappeared like it was never started. I searched for all possible reasons for why its not getting installed on my laptop, I used registry cleaner s/w,  deleted 25 GB of data to create free space if it were the problem, increased the virtual memory to increase the space for RAM, I did almost everything to get this setup working, but I found no success with the "Create and Configure database" option

and

then

I chose a "database software only" option and chose to store in a folder w/o spaces. This way, I got database s/w only and then later I found "Database configuration Assistant (DBCA)"  from windows START button and clicked to create and configure database manually. The steps are pretty much interactive and doesn't involve much brainstorming.

The values I filled for

1) Global Database Name :  orcl

2) System Identifier : orcl

3) I chose common password for both SYS and SYSTEM

4) while on Enterprise Manager Configuration step, It asked me to create and configure listener in oracle home, so for that too, I typed "netca" in windows START menu and clicked it. There I added a listener.

5) I chose a Storage area which was the Oracle-home itself i.e. where our installation files goes , in my case it is : C:\oracle_base\product\11.2.0\dbhome_1\oradata

6) Then after few more nitty-gritty clicks, we are set to go !

Finally to write SQL code and to create your first TABLE , type "sqlplus" in windows "START" menu and click it when it appears. A command-prompt like window appears , which will ask you for username and password, so here they are :

Username : sys/ as sysdba

Password : (its the one you created in step 3 stated above )

After this you are ready to write your first SQL command.

History of Computers

Computer is a device, which has the capability to solve any kind of problem, related to calculations. It has very high speed of calculating power.It is a general purpose device, which nowadays has increased its domain, and has included the area of entertainment too. You can watch movies, listen songs, draw paintings,compose your own music, make your own videos and much more things.

Today's computers have become a very much part of almost everyone's life.People have become so use to of computers that they feel incomplete without them.