Thursday, 23 April 2015

what is the Subnet Mask

The Portion of the IP address that defines the network, as opposed to identifying a particular computer.  For example, a computer with an IP address of 192.168.1.5 might have a subnet mask of 255.255.255.0 The portion of the address that reads 192.168.1 is the network address and the .5 is the address that reads 192.168.1 is the network address and the .5 is the address of the specific machine on that network.  The subnet mask explains that the first three numbers in a dotted-decimal address(for example, 192.168.1 are the network and that the last number denotes a specific computer on that network.

Monday, 20 April 2015

what is IP address

A device on a network need IP address to communicate with other device.  IP address is a unique with other device.  IP address is unique and 32 bit logic address a IP address used to communicate with various networking devices over a network layer.

Dynamic IP Address-  Are assign to the devices that require temporary connectivity to the network or non permanent device.  The most common protocol used to assign dynamic IP address is dynamic host configuration protocol DHCP.

Static IP Address-  Static IP address are leaving assign to network device whose device in a longer duration.  Example:  Server

Wednesday, 1 April 2015

Database on a Network

A Networked Database Management System (NDBMS) is an application that synchronizes multiple user' access to centralized databases.  There are two basic forms of networked databases;

Tuesday, 3 March 2015

Relational and Flat-file Databases

A DBMS that uses only a single table is called a flat-file database.  But a DBMS can go further: Several tables can be related to each other and the DBMS can access them in a synchronized way to create highly detailed analyses and meaning ful relationships between their various fields(or subsets of fields).

In other words, the DBMS takes raw forms relationships that turn it into useful information. This ability to synchronize relationships between tables is far easier for a computer than a human being. 
To visualize how a computer works with related tables in a database, imagine a company that ships a variety of products to customers,  The company maintains a table of customers, including a customers ID number, name and shipping addresses.  If the company had to add a field to the customer table each time a customer ordered a product, the table would quickly become bloated, full of fields that not all customer records would necessarily need.

Instead product numbers, names and prices are stored in a separate inventory table.  When a customer orders products, just product numbers, long with customer's ID number, are copied into the third table, a shipping/invoicing table.  This third table is very small because only the relevant ID numbers are duplicated.  The shipping/invoicing table can be sorted on the customer's Id number and invoice number, to keep all the ordered items together.  The details about the customer and the products remain in their respective customer and inventory tables.  The DBMS can print shipping orders and invoices based on the small table, using the ID numbers to look up the details about customers and products remain in their respective customer and inventory tables.

The DBMS can print shipping orders and invoices based on the small table, using the ID numbers to look up the details about customers and products, While this process would be tedious for human beings, it is easy for a computer.  The relational databases saves disk space especially as shipping and invoicing records accumulate.  The shipping/invoicing table,with its tree fields is much easier for a computer to sort and maintain than a single table with many fields.  The multiple file the relational database model can be applied to  many different types of business record keeping.  For example, you can relate a mailing list to a set of a demographic categories, a single student to multiple records to classes taken and grades received; a single accounting code to multiple instances of expenses and income, and so on.

Saturday, 28 February 2015

The Structure of Data table

A Database framework organizes raw data into a hierarchy of relationships.  At the lowest level of this hierarchy, the data is broken down into fundamental building blocks, called fields.  A field defines an aspect of that data that is common to all instances of it; for example, a Last Name field would contain persons' last names and a firs name field would contain their first names.

Fields are combined into record.  A very simple record might consist of first and last name fields and each record would then contain the full name of a person.

A set of such records is called a table (or in some systems, a data file or file).  A phone book is real world example of a table.  For each listing in the phone book, there are three fields: one for names, another for addresses and another for phone number-forms a records.  The records are alphabetized into a list and bound together to make up the table/phone book.

By breaking up data in to fields and records, a DBMS can access and sort the data very quickly.  For example, a DBMS can sort a mailing list alphabetically using the Last Name and First Name fields and sort it ZIP code other by using a ZIP code field.

Thursday, 26 February 2015

What is database

There are a large number of networked database products on the market, but they all have the same fundamental purpose: to provide a centralized repository data, allowing multiple users to access it, update it and produce meaningful information based on it, all the while protecting it  from accidental corruption and enforcing your business rules for keeping it accurate and reliable.  That's a large job for a software program and many programs require the ongoing support of a skilled database manager.

The integrity of the database is vital to the survival of many large and small businesses today.  A Database Management System (DBMS) is an application that organizes data into the framework and uses that framework to provide access to the data and vehicle for processing modifying) it.

What is Shell Account

Usint dialup access to the HOST computer.  By connecting to the host computer, the users to be able to use all Intenet services.  In this mode,the users would be using a simple terminal emulation from their PCs and will require any special software on their machine.