NIC & LAN CARD

Q1: What is Network
A network consists of two or more computers that are linked in order to share resources (such as printers and CDs), exchange files, or allow electronic communications. The computers on a network may be linked through cables, telephone lines, radio waves, satellites, or infrared light beams.

Q2 : What is Network Types ?

Local Area Network

A Local Area Network (LAN) is a network that is confined to a relatively small area. It is generally limited to a geographic area such as a writing lab, school, or building.
Computers connected to a network are broadly categorized as servers or workstations. Servers are generally not used by humans directly, but rather run continuously to provide "services" to the other computers (and their human users) on the network. Services provided can include printing and faxing, software hosting, file storage and sharing, messaging, data storage and retrieval, complete access control (security) for the network's resources, and many others.
Workstations are called such because they typically do have a human user which interacts with the network through them. Workstations were traditionally considered a desktop, consisting of a computer, keyboard, display, and mouse, or a laptop, with with integrated keyboard, display, and touchpad. With the advent of the tablet computer, and the touch screen devices such as iPad and iPhone, our definition of workstation is quickly evolving to include those devices, because of their ability to interact with the network and utilize network services.

Wide Area Network

Wide Area Networks (WANs) connect networks in larger geographic areas, such as Florida, the United States, or the world. Dedicated transoceanic cabling or satellite uplinks may be used to connect this type of global network.
Using a WAN, schools in Florida can communicate with places like Tokyo in a matter of seconds, without paying enormous phone bills. Two users a half-world apart with workstations equipped with microphones and a webcams might teleconference in real time. A WAN is complicated. It uses multiplexers, bridges, and routers to connect local and metropolitan networks to global communications networks like the Internet. To users, however, a WAN will not appear to be much different than a LAN.

METROPOLITAN AREA NETWORK

A metropolitan area network (MAN) is a network that interconnects users with computer resources in a geographic area or region larger than that covered by even a large local area network (LAN) but smaller than the area covered by a wide area network (WAN). The term is applied to the interconnection of networks in a city into a single larger network (which may then also offer efficient connection to a wide area network). It is also used to mean the interconnection of several local area networks by bridging them with backbone lines. The latter usage is also sometimes referred to as a campus network.

Q3 : How to we can install Lan Card ?

Step 1. Go to a computer whose network connection is available. Download Driver Talent for Network Card via the button below and save the .EXE file to a USB drive. (If you have not such computer around you, you can also download the utility via your iPhone or Android phone or other network available devices.)

Step 2. Connect the USB drive to your computer and copy the installer file. Then run the .EXE file to install Driver Talent for Network Card.

Step 3. Launch the utility and it will start scanning automatically without any advanced configuration. (Are you wondering when the network driver is installed? It is installed during the process of installing Driver Talent for Network Card.) Once this tool is installed, the network driver is installed successfully.

Step 4. Restart the computer. You will see that the computer has Internet access again. If you want to install other drivers, you can complete all the jobs with one "Update" or "Download" click.

VMWARE

Contributor(s): YUVRAJ SINGH MEWARA

Q1 : What is vmwara?

VMware is a virtualization and cloud computing software provider based in Palo Alto, California. Founded in 1998, VMware is a subsidiary of Dell Technologies. EMC Corporation originally acquired VMware in 2004; EMC was later acquired by Dell Technologies in 2016. VMware bases its virtualization technologies on its bare-metal hypervisor ESX/ESXi in x86 architecture.

With VMware server virtualization, a hypervisor is installed on the physical server to allow for multiple virtual machines (VMs) to run on the same physical server. Each VM can run its own operating system (OS), which means multiple OSes can run on one physical server. All of the VMs on the same physical server share resources, such as networking and RAM.
Diane Greene, Scott Devine, Mendel Rosenblum, Edward Wang and Edouard Bugnion founded VMware, which launched its first product -- VMware Workstation -- in 1999. The company released its second product, VMware ESX in 2001.
VMware's current CEO is Patrick P. Gelsinger, appointed in 2012.

Q2: Installation of VMWARE?

Installing VMware

Insert the Windows 10 CD or DVD in the CD-ROM drive.
Start the virtual machine. This begins the Windows installation.
(Optional) If you are using VMware Paravirtual as the default SCSI controller, install the pvscsi driver.
1. When Windows installer displays the screen, Where do you want to install Windows, switch the current virtual machine's CD drive to point to the VMware Tools .iso image.
  For example, in the vSphere client:
  Right click the virtual machine and select Guest > Install/Update VMware Tools.
2. From the installer screen, Where do you want to install Windows, click Load driver.
3. From the installer screen, Select the driver to install, click Browse and browse to the pvscsi driver directory in the VMware Tools .iso image.
  Select the driver appropriate to your Windows operating system:
  - for 64-bit OS: select CD Driver/Program Files/VMware/VMware Tools/Drivers/pvscsi/amd64
  - for 32-bit OS: select CD Driver/Program Files/VMware/VMware Tools/Drivers/pvscsi/
4. Click OK, wait until the pvscsi driver is recognized successfully, then click Next.
5. When the installer displays the Where do you want to install Windows screen, switch the virtual machine's CD drive to the Windows installation disk and continue the Windows installation.
  For example, in the vSphere client:
  1. Click the CD icon and select CD/DVD driver1 > Disconnect from ...
  2. Click the CD icon again and select the Windows .iso image.
6. Click Next to continue the Windows installation.
  If the Next button is gray and cannot be clicked, click Refresh, then re-click Next.
Follow the prompts to complete the installation.
Install VMware Tools.
(Optional) On VMware Fusion, install Boot Camp drivers so that the guest operating system can access hardware devices on the physical machine.
Boot Camp 5.1 supports 64-bit Windows. For more information, refer to http://support.apple.com/en-us/HT204048.

DIFFERECE BETWEEN LINUX & OPERATING SYSTEM

Both macOS and Linux are versions of Unix. There are a very large number of similarities. Almost all major Linux software has a Mac version.

The main differences are…

Linux is a way better solution for mass deployment on server and embedded applications. macOS is optimised to be a sort of pro-sumer OS.
macOS has hardware drivers for only a very narrow set of Apple hardware. Linux is far more hardware agnostic. ( although the quality of some Linux drivers can be patchy. )
macOS is a more viable commercial platform for software developers. So if you want specific apps for productivity, media production etc, there are more commercial options for the Mac. Both because of the development tools and the options to sell software to paying customers. And this is in part due to…
The Mac has Cocoa. Which is arguably the best API for developing GUI software in existence. There is no direct equivalent on Linux. (with the closest thing being QT and GTK+) - As a consequence, software developed with Cocoa tends to mirror systemwide design and operates consistently with the OS.

This last point is perhaps the most important differentiator. Someone making applications for the Mac has a huge amount of frameworks available that work seamlessly together, so if you are building a media application, or a word processor, or a scientific tool. There are pre-fabricated objects which can be used to build your app. This results in Mac software feeling more polished and working consistently.

And when you are done, the app will look like a native Mac application and integrate with all the recent system features.

#1: Full access vs. no access

Having access to the source code is probably the single most significant difference between Linux and Windows. The fact that Linux belongs to the GNU Public License ensures that users (of all sorts) can access (and alter) the code to the very kernel that serves as the foundation of the Linux operating system. You want to peer at the Windows code? Good luck. Unless you are a member of a very select (and elite, to many) group, you will never lay eyes on code making up the Windows operating system.

You can look at this from both sides of the fence. Some say giving the public access to the code opens the operating system (and the software that runs on top of it) to malicious developers who will take advantage of any weakness they find. Others say that having full access to the code helps bring about faster improvements and bug fixes to keep those malicious developers from being able to bring the system down. I have, on occasion, dipped into the code of one Linux application or another, and when all was said and done, was happy with the results. Could I have done that with a closed-source Windows application? No.

#2: Licensing freedom vs. licensing restrictions

Along with access comes the difference between the licenses. I'm sure that every IT professional could go on and on about licensing of PC software. But let's just look at the key aspect of the licenses (without getting into legalese). With a Linux GPL-licensed operating system, you are free to modify that software and use and even republish or sell it (so long as you make the code available). Also, with the GPL, you can download a single copy of a Linux distribution (or application) and install it on as many machines as you like. With the Microsoft license, you can do none of the above. You are bound to the number of licenses you purchase, so if you purchase 10 licenses, you can legally install that operating system (or application) on only 10 machines.

#3: Online peer support vs. paid help-desk support

This is one issue where most companies turn their backs on Linux. But it's really not necessary. With Linux, you have the support of a huge community via forums, online search, and plenty of dedicated Web sites. And of course, if you feel the need, you can purchase support contracts from some of the bigger Linux companies (Red Hat and Novell for instance).

However, when you use the peer support inherent in Linux, you do fall prey to time. You could have an issue with something, send out e-mail to a mailing list or post on a forum, and within 10 minutes be flooded with suggestions. Or these suggestions could take hours of days to come in. It seems all up to chance sometimes. Still, generally speaking, most problems with Linux have been encountered and documented. So chances are good you'll find your solution fairly quickly.

On the other side of the coin is support for Windows. Yes, you can go the same route with Microsoft and depend upon your peers for solutions. There are just as many help sites/lists/forums for Windows as there are for Linux. And you can purchase support from Microsoft itself. Most corporate higher-ups easily fall victim to the safety net that having a support contract brings. But most higher-ups haven't had to depend up on said support contract. Of the various people I know who have used either a Linux paid support contract or a Microsoft paid support contract, I can't say one was more pleased than the other. This of course begs the question "Why do so many say that Microsoft support is superior to Linux paid support?"

#4: Full vs. partial hardware support

One issue that is slowly becoming nonexistent is hardware support. Years ago, if you wanted to install Linux on a machine you had to make sure you hand-picked each piece of hardware or your installation would not work 100 percent. I can remember, back in 1997-ish, trying to figure out why I couldn't get Caldera Linux or Red Hat Linux to see my modem. After much looking around, I found I was the proud owner of a Winmodem. So I had to go out and purchase a US Robotics external modem because that was the one modem I knew would work. This is not so much the case now. You can grab a PC (or laptop) and most likely get one or more Linux distributions to install and work nearly 100 percent. But there are still some exceptions. For instance, hibernate/suspend remains a problem with many laptops, although it has come a long way.

With Windows, you know that most every piece of hardware will work with the operating system. Of course, there are times (and I have experienced this over and over) when you will wind up spending much of the day searching for the correct drivers for that piece of hardware you no longer have the install disk for. But you can go out and buy that 10-cent Ethernet card and know it'll work on your machine (so long as you have, or can find, the drivers). You also can rest assured that when you purchase that insanely powerful graphics card, you will probably be able to take full advantage of its power.

#5: Command line vs. no command line

No matter how far the Linux operating system has come and how amazing the desktop environment becomes, the command line will always be an invaluable tool for administration purposes. Nothing will ever replace my favorite text-based editor, ssh, and any given command-line tool. I can't imagine administering a Linux machine without the command line. But for the end user — not so much. You could use a Linux machine for years and never touch the command line. Same with Windows. You can still use the command line with Windows, but not nearly to the extent as with Linux. And Microsoft tends to obfuscate the command prompt from users. Without going to Run and entering cmd (or command, or whichever it is these days), the user won't even know the command-line tool exists. And if a user does get the Windows command line up and running, how useful is it really?

#6: Centralized vs. noncentralized application installation

The heading for this point might have thrown you for a loop. But let's think about this for a second. With Linux you have (with nearly every distribution) a centralized location where you can search for, add, or remove software. I'm talking about package management systems, such as Synaptic. With Synaptic, you can open up one tool, search for an application (or group of applications), and install that application without having to do any Web searching (or purchasing).

Windows has nothing like this. With Windows, you must know where to find the software you want to install, download the software (or put the CD into your machine), and run setup.exe or install.exe with a simple double-click. For many years, it was thought that installing applications on Windows was far easier than on Linux. And for many years, that thought was right on target. Not so much now. Installation under Linux is simple, painless, and centralized.

#7: Flexibility vs. rigidity

I always compare Linux (especially the desktop) and Windows to a room where the floor and ceiling are either movable or not. With Linux, you have a room where the floor and ceiling can be raised or lowered, at will, as high or low as you want to make them. With Windows, that floor and ceiling are immovable. You can't go further than Microsoft has deemed it necessary to go.

Take, for instance, the desktop. Unless you are willing to pay for and install a third-party application that can alter the desktop appearance, with Windows you are stuck with what Microsoft has declared is the ideal desktop for you. With Linux, you can pretty much make your desktop look and feel exactly how you want/need. You can have as much or as little on your desktop as you want. From simple flat Fluxbox to a full-blown 3D Compiz experience, the Linux desktop is as flexible an environment as there is on a computer.

#8: Fanboys vs. corporate types

I wanted to add this because even though Linux has reached well beyond its school-project roots, Linux users tend to be soapbox-dwelling fanatics who are quick to spout off about why you should be choosing Linux over Windows. I am guilty of this on a daily basis (I try hard to recruit new fanboys/girls), and it's a badge I wear proudly. Of course, this is seen as less than professional by some. After all, why would something worthy of a corporate environment have or need cheerleaders? Shouldn't the software sell itself? Because of the open source nature of Linux, it has to make do without the help of the marketing budgets and deep pockets of Microsoft. With that comes the need for fans to help spread the word. And word of mouth is the best friend of Linux.

Some see the fanaticism as the same college-level hoorah that keeps Linux in the basements for LUG meetings and science projects. But I beg to differ. Another company, thanks to the phenomenon of a simple music player and phone, has fallen into the same fanboy fanaticism, and yet that company's image has not been besmirched because of that fanaticism. Windows does not have these same fans. Instead, Windows has a league of paper-certified administrators who believe the hype when they hear the misrepresented market share numbers reassuring them they will be employable until the end of time.

#9: Automated vs. nonautomated removable media

I remember the days of old when you had to mount your floppy to use it and unmount it to remove it. Well, those times are drawing to a close — but not completely. One issue that plagues new Linux users is how removable media is used. The idea of having to manually "mount" a CD drive to access the contents of a CD is completely foreign to new users. There is a reason this is the way it is. Because Linux has always been a multiuser platform, it was thought that forcing a user to mount a media to use it would keep the user's files from being overwritten by another user. Think about it: On a multiuser system, if everyone had instant access to a disk that had been inserted, what would stop them from deleting or overwriting a file you had just added to the media? Things have now evolved to the point where Linux subsystems are set up so that you can use a removable device in the same way you use them in Windows. But it's not the norm. And besides, who doesn't want to manually edit the /etc/fstab fle?

#10: Multilayered run levels vs. a single-layered run level

I couldn't figure out how best to title this point, so I went with a description. What I'm talking about is Linux' inherent ability to stop at different run levels. With this, you can work from either the command line (run level 3) or the GUI (run level 5). This can really save your socks when X Windows is fubared and you need to figure out the problem. You can do this by booting into run level 3, logging in as root, and finding/fixing the problem.

With Windows, you're lucky to get to a command line via safe mode — and then you may or may not have the tools you need to fix the problem. In Linux, even in run level 3, you can still get and install a tool to help you out (hello apt-get install APPLICATION via the command line). Having different run levels is helpful in another way. Say the machine in question is a Web or mail server. You want to give it all the memory you have, so you don't want the machine to boot into run level 5. However, there are times when you do want the GUI for administrative purposes (even though you can fully administer a Linux server from the command line). Because you can run the startx command from the command line at run level 3, you can still start up X Windows and have your GUI as well. With Windows, you are stuck at the Graphical run level unless you hit a serious problem.

How to install the Windows operating system

Each version of Microsoft Windows is installed on a computer using similar steps. While there are steps in the installation process that can differ between versions of Windows, the following general steps and guidelines will help you to install Windows on your computer.

Note: If you have an OEM computer (e.g., Acer, Dell, Hewlett-Packard, etc.) the computer would not have a Windows CD, DVD, or USB thumb drive. Instead, you would re-install Windows and all the software using a hidden partition. The steps mentioned on this page would still work, but you'd need a copy of Windows.

The steps below are for all recent versions of Windows, including Windows 98, Windows ME, Windows 2000, Windows XP, Windows Vista, Windows 7, Windows 8, and Windows 10. These steps would even work for earlier versions (e.g., Windows 95) as long as you're using the disc version. The floppy diskette version is similar but would require additional steps.

Tip: If you want to upgrade to a newer version of Windows on your computer, the steps below can help you with the upgrade process. The Windows installation process should recognize if you have an older version of Windows already installed on the computer and ask if you want to upgrade or perform a fresh install. The upgrade process will install the newer Windows operating system files over top the old ones and preserve your personal files.

Genuine Windows CD, DVD, or USB thumb drive

First, you will need a genuine copy of the Microsoft Windows operating systeminstallation CD, DVD, or USB thumb drive. A genuine Windows product key is included with the installation disc, which is required to activate Windows after installation. If you have an OEM computer, the product key for your version of Windows is also often on the back or side of the computer.

Tip: You can borrow a disc from a friend as long as you're installing the same version of Windows that came with the computer and you had the product key for that version of Windows.

Note: With early versions of Windows, you cannot download a copy of Windows to install on a computer. You must purchase a physical copy of Windows. If you are installing Windows 10, you can download the Windows 10 creation tool to create a bootable disc or USB thumb drive.

Warning: Microsoft only has Windows 10 available for download from their website. Any other site that claims to have copies of other versions of Windows should not be trusted. These copies of Windows are pirated software and could contain anything including spyware or malware.

Installing Windows

To start the Windows installation process, you will need to configure your computer to boot from a CD or DVD before booting to the hard drive. Changing the boot process forces the computer to look for the Windows installation disc before trying to boot from the hard drive.

Access the computer's BIOS setup.
Change the computer's boot order, setting the CD, DVD or disc drive as the first boot device if you are trying to boot from a disc or a USB drive if you're trying to boot from a USB thumb drive.
Save the settings change and exit BIOS.

Once you have updated the boot order, you can begin the Windows installation process.

Place the Windows installation disc in the CD/DVD drive or USB thumb drive into the back of the computer.
Turn on or restart the computer. As the computer is starting up, it should see the installation disc or drive and show a message similar to Press any key to boot from CD. Press any key on the keyboard to have the computer boot from the installation disc or drive.
The Windows installation process will begin. There will be different prompts that you will need to answer. Select either Yes or the appropriate option to install Windows.

Tip: Make sure you select the full Windows installation option and not the Windows repair option.

You may be asked if you want to erase all contents on the hard drive, then install Windows. It is recommended that you choose this option, as it will also properly format the hard drive to allow the Windows operating system to be installed.
The computer may need to restart several times during the Windows installation process. The restarts are normal and if prompted to restart, select the Yes option.
When the installation process is nearly complete, the Windows configuration option screens is shown. On these screens, you may be asked to select the time zone you live in, your preferred language, and the name of the account you will use to access Windows. Select the appropriate options and enter the appropriate information on each configuration screen.

The Windows installation process will be complete when the computer prompts you to log in with the account you just created on the configuration screens or when it loads directly into Windows.

Final Windows and computer configuration

After Windows has been installed on the computer, you will need to install the driversand related software for the hardware in the computer. You can use the installation discs that came with the hardware, or you can download the drivers from the hardware manufacturer's website.

Tip: If you cannot download drivers because your network card is not working after installing Windows you can download the drivers on another computer and then copy them to a USB thumb drive and move them over to your computer.

How to install and update a computer driver

It is strongly recommended that you install the latest drivers for each piece of hardware.

To determine which hardware needs drivers to be installed, check the Device Managerand look for exclamation mark "!" next to hardware devices. The exclamation point means drivers are needed for that device.

After installing the necessary hardware device drivers, install any software programs on the computer that you want to use.

Finally, download and install any available Windows updates. Updating Windows can help improve the performance of the operating system, the hardware in the computer, and software programs you use. It can also improve security by fixing potential security holes and flaws in Windows.

How to update a Microsoft Windows computer

Long-term maintenance of Windows

Microsoft frequently releases new updates for Windows, so it is recommended that you check for and install available updates. Doing so will help keep Windows running better and keep your computer protected.

Also, periodically check for updated hardware device drivers from manufacturers' websites. Keeping hardware drivers updated can help the hardware devices in the computer to run at peak performance and improve compatibility with other hardware and software in the computer.

Discuss different functions of operating system. Operating system performs the following functions:

1. Booting: Booting is a process of starting the computer operating system starts the computer to work. It checks the computer and makes it ready to work.

2. Memory Management

It is also an important function of operating system. The memory cannot be managed without operating system. Different programs and data execute in memory at one time. if there is no operating system, the programs may mix with each other. The system will not work properly.

3. Loading and Execution

A program is loaded in the memory before it can be executed. Operating system provides the facility to load programs in memory easily and then execute it.

4. Data security

Data is an important part of computer system. The operating system protects the data stored on the computer from illegal use, modification or deletion.

5. Disk Management

Operating system manages the disk space. It manages the stored files and folders in a proper way.

6. Process Management

CPU can perform one task at one time. if there are many tasks, operating system decides which task should get the CPU.

7. Device Controlling

operating system also controls all devices attached to computer. The hardware devices are controlled with the help of small software called device drivers.

8. Printing controlling

Operating system also controls printing function. It a user issues two print commands at a time, it does not mix data of these files and prints them separately.

9. Providing interface

It is used in order that user interface acts with a computer mutually. User interface controls how you input data and instruction and how information is displayed on screen. The operating system offers two types of the interface to the user:

1. Graphical-line interface: It interacts with of visual environment to communicate with the computer. It uses windows, icons, menus and other graphical objects to issues commands.

2. Command-line interface: it provides an interface to communicate with the computer by typing commands.

operating system (OS)

An operating system (OS) is the program that, after being initially loaded into the computer by a boot program, manages all the other programs in a computer. The other programs are called applications or application programs. The application programs make use of the operating system by making requests for services through a defined application program interface (API). In addition, users can interact directly with the operating system through a user interface such as a command line or a graphical user interface (GUI).

An operating system performs these services for applications:

In a multitasking operating system where multiple programs can be running at the same time, the operating system determines which applications should run in what order and how much time should be allowed for each application before giving another application a turn.
It manages the sharing of internal memory among multiple applications.
It handles input and output to and from attached hardware devices, such as hard disks, printers, and dial-up ports.
It sends messages to each application or interactive user (or to a system operator) about the status of operation and any errors that may have occurred.
It can offload the management of what are called batch jobs (for example, printing) so that the initiating application is freed from this work.
On computers that can provide parallel processing, an operating system can manage how to divide the program so that it runs on more than one processor at a time.

All major computer platforms (hardware and software) require and sometimes include an operating system, and operating systems must be developed with different features to meet the specific needs of various form factors.

Common desktop operating systems:

Windows is Microsoft’s flagship operating system, the de facto standard for home and business computers. Introduced in 1985, the GUI-based OS has been released in many versions since then. The user-friendly Windows 95 was largely responsible for the rapid development of personal computing.

Mac OS is the operating system for Apple's Macintosh line of personal computers and workstations.

Linux is a Unix-like operating system that was designed to provide personal computer users a free or very low-cost alternative. Linux has a reputation as a very efficient and fast-performing system.

Windows operating systems have long dominated the market and continue to do so. As of August 2016, Windows systems had a market share of over 85 percent. In contrast, Mac OS was at a little over 6 percent and Linux was just over 2 percent. Nevertheless, Windows is losing market share from a long-held 90 percent and higher.

A mobile OS allows smartphones, tablet PCs and other mobile devices to run applications and programs. Mobile operating systems include Apple iOS, Google Android, BlackBerry OS and Windows 10 Mobile.

An embedded operating system is specialized for use in the computers built into larger systems, such as cars, traffic lights, digital televisions, ATMs, airplane controls, point of sale (POS) terminals, digital cameras, GPS navigation systems, elevators, digital media receivers and smart meters.

Relational Operator

Relational Algebra is procedural query language, which takes Relation as input and generate relation as output. Relational algebra mainly provides theoretical foundation for relational databases and SQL.

Operators in Relational Algebra

Projection (π)
Projection is used to project required column data from a relation.

Example :

π (BC) 
B  C
-----
2  4
2  3
3  4

Note: By Default projection removes duplicate data.

Selection (σ)
Selection is used to select required tuples of the relations.

for the above relation
σ (c>3)R
will select the tuples which have c more than 3.

Note: selection operator only selects the required tuples but does not display them. For displaying, data projection operator is used.

For the above selected tuples, to display we need to use projection also.

 π (σ (c>3)R ) will show following tuples.

A  B  C
-------
1  2  4
4  3  4

Union (U)
Union operation in relational algebra is same as union operation in set theory, only constraint is for union of two relation both relation must have same set of Attributes.

Set Difference (-)
Set Difference in relational algebra is same set difference operation as in set theory with the constraint that both relation should have same set of attributes.

Rename (ρ)
Rename is a unary operation used for renaming attributes of a relation.
ρ (a/b)R will rename the attribute ‘b’ of relation by ‘a’.

Cross Product (X)

Cross product between two relations let say A and B, so cross product between A X B will results all the attributes of A followed by each attribute of B. Each record of A will pairs with every record of B.

below is the example

   A                                  B
    (Name   Age  Sex )                (Id   Course)  
    ------------------                -------------
    Ram    14   M                      1     DS
    Sona   15   F                      2     DBMS
    kim    20   M

     A X B
  Name   Age   Sex   Id   Course
---------------------------------
  Ram    14    M      1    DS
  Ram    14    M      2    DBMS
  Sona   15    F      1    DS
  Sona   15    F      2    DBMS
  Kim    20    M      1    DS
  Kim    20    M      2    DBMS

Note: if A has ‘n’ tuples and B has ‘m’ tuples then A X B will have ‘n*m’ tuples.

Natural Join (⋈)

Natural join is a binary operator. Natural join between two or more relations will result set of all combination of tuples where they have equal common attribute.

Let us see below example

 
           Emp                              Dep
   (Name   Id   Dept_name )          (Dept_name   Manager)
   ------------------------          ---------------------    
     A     120    IT                    Sale     Y
     B     125    HR                    Prod     Z
     C     110    Sale                  IT       A
     D     111    IT                      


Emp ⋈ Dep

Name   Id   Dept_name   Manager
-------------------------------
A     120   IT          A 
C     110   Sale        Y
D     111   IT          A

Conditional Join

Conditional join works similar to natural join. In natural join, by default condition is equal between common attribute while in conditional join we can specify the any condition such as greater than, less than, not equal

Let us see below example

         R                           S
  (ID   Sex   Marks)          (ID   Sex   Marks)
  ------------------          -------------------- 
   1   F   45                   10   M   20
   2   F   55                   11   M   22
   3   F   60                   12   M   59
 
Join between R And S with condition  R.marks >= S.marks

R.ID   R.Sex   R.Marks   S.ID   S.Sex   S.Marks
-----------------------------------------------
1       F       45        10     M        20
1       F       45        11     M        22
2       F       55        10     M        20
2       F       55        11     M        22
3       F       60        10     M        20
3       F       60        11     M        22
3       F       60        12     M        59

Relational Set Operators uses relational algebra to manipulate contents in a database. All together there are eight different types of operators. These operators are SQL commands.

The first operator is the UNION. It combines all of the rows in one table with all of the rows in another table except for the duplicate tuples. The tables are required to have the same attribute characteristics for the Union command to work. The tables must be union-compatible which means that two tables being used have the same amount of columns and the columns have the same names, and also need to share the same domain. Relational Set Operators uses relational algebra to manipulate contents in a database. All together there are eight different types of operators. These operators are SQL commands.

INTERSECT is the second SQL command that takes two tables and combines only the rows that appear in both tables. The tables must be union-compatible to be able to use the Intersect command or else it won't work.

DIFFERENCE in another SQL command that gets all rows in one table that are not found in the other table. Basically it subracts one table from the other table to leave only the attributes that are not the same in both tables. For this command to work both tables must be union-compatible.

PRODUCT command would show all possible pairs of rows from both tables being used. This command can also be referred to as the Cartesian Product.

SELECT is the command to show all rows in a table. It can be used to select only specific data from the table that meets certain criteria. This command is also referred to as the Restrict command.

PROJECT is the command that gives all values for certian attributes specified after the command. It shows a vertical view of the given table.

JOIN takes two or more tables and combines them into one table. This can be used in combination with other commands to get specific information. There are several types of the Join command. The Natural Join, Equijion, Theta Join, Left Outer Join and Right Outer Join. been DIVIDE has specific requirements of the table. One of the tables can only have one column and the other table must have two columns only.INTERSECT is the second SQL command that takes two tables and combines only the rows that appear in both tables. The tables must be union-compatible to be able to use the Intersect command or else it won't work.

PRODUCT command would show all possible pairs of rows from both tables being used. This command can also be referred to as the Cartesian Product.

PROJECT is the command that gives all values for certian attributes specified after the command. It shows a vertical view of the given table.

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_ YUVRAJ SINGH MEWARA, Google Inc. _

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