400-051 Dumps PDF Cisco Exam
Chapter 1. Getting Started
Since the beginning of human history, people 400-051 dumps cisco 400-051 dumps had to work with data. In the early days, data was stored on stones or on other ancient media. The idea was to store data in such a way that other people could use it. At first, simple pictographs were drawn to code various fragments of information. With the invention of the alphabet, storing data became easier and communication was constantly improved 400-051.
400-051 dumps With the ability to store information, it was also possible to share knowledge with others and to have some sort of backup for the human brain. Looking at the process from a modern point of view, it was all about storing and retrieving data in such a way that people could work with the information. This is exactly what people are doing today. The ¡°stone computers¡± have been replaced by highly sophisticated clusters or personal computers. Data is not transmitted on stones any more, but is sent across fiber cable networks within hundredths of a second. No matter which methods have been used or which methods are still used today, the basic ideas of IT are still the same: Storing, retrieving, and displaying data are still the fundamentals of every system, and I guess things won¡¯t change in the next few centuries. It is all about information and it still will be about information in the future.
With the invention of the alphabet and writing in general, it became possible to describe things. Using letters, it is possible to build words and phrases. Alphabets and languages are fundamental components that every culture relies on. For a long time humans have used language to interact with other humans. In recent times, it has become very popular to interact with computers. However, the way interaction is done is still the same. Characters are used to tell the partner what to do and what has happened.
Because computers cannot understand human languages, new forms of communications have been invented. Programming languages were developed for working with machines and telling them what to do.
With the arrival of modern technologies such as the Internet, more and more specialized and highly optimized languages have been developed. One of these languages is called PHP. PHP was designed for building Web sites. Of course, PHP can be used as an ordinary programming language, but the main purpose of PHP is to work in combination with network environments. The language is a child of the Internet and the father of many Web sites all around the globe. Millions of Web sites have been built with the help of PHP, and it has been installed on thousands of servers.
To store data efficiently, databases can be used. One of these databases is PostgreSQL, a flexible and easy-to-use platform for working with millions of pieces of information. PostgreSQL is a so-called object relational database, which means that it offers more features than a purely relational database.
1.1 Why Use PHP and PostgreSQL as a Team?
At the beginning of the Internet age, many Web sites were based on Perl applications, which were using the CGI interface. With the help of the CGI interface, it is possible to use every programming language for generating HTML code on-the-fly. The programming language Perl is optimized for building text processors, so it is a great tool for building Web sites. HTML code is based on text, so dynamic pages can easily be generated. However, Perl was not designed to be a Web language.
Especially when running Perl, using the CGI interface is very common. Other programming languages such as PHP can have several advantages over Perl because PHP has been optimized for the Web. Of course, you can use mod_perl, but an increasing number of people rely on PHP.
Both PHP and PostgreSQL are open source, which means that the source code of PHP and PostgreSQL can be used and distributed freely. Using open source software has several advantages:
Costs You don¡¯t have to pay for the software, which helps reduce the total cost of your software projects.
software is said to be more secure than commercial software. In many cases security updates for free software are available quickly, so severe security problems will not last a long time.
Information When using commercial software, you might not know exactly what a certain component does. In this case free software will be helpful because you just have to look at the source code of PHP or PostgreSQL and you will find out what the code does.
Independence Free software helps you to gain independence from software manufacturers. This is important because you need not follow the update path proposed by a big player in the software business.
Quality In most cases free software contains high-quality code. People implementing open source are highly motivated, so free software offers stability as well as flexibility.
software offers the
possibility to modify the
software to your needs.
Features can be added
easily, and in addition,
you can optimize the software for your
The last point especially is truly an important one. ¡°Free software is not free beer¡±this is what Richard M. Stallman, the father of free software, has to say about open source. Freedom means that nobody can force you to stick to a concept and nobody threatens your personal freedom. If you have no chance to modify your software, your mind is not free and this must be avoided.
Today a variety of free databases are available. Many developers rely on databases such as MySQL. MySQL offers a special version of SQL that is not ANSI-SQLcompliant. Especially when porting MySQL applications to other databases, MySQL¡¯s incompatibility is a real problem because you might have to rewrite or at least modify major parts of your SQL code. In addition, PostgreSQL provides highly sophisticated features such as inheritance, triggers, and embedded languages.
In contrast to MySQL, PostgreSQL is ANSI 400-051 dumps pdf latest 400-051 dumps compliant. Therefore porting applications to PostgreSQL is an easy task, and it is also possible to switch from PostgreSQL to a commercial database such as DB2 or Oracle.