WEBVTT 00:00.980 --> 00:03.320 Okay, so let's talk about PHP. 00:03.680 --> 00:08.450 The first and the most important question is what's p.h.p. 00:08.480 --> 00:16.310 Well, it is a server side programming language and it was designed for web development in mind. 00:16.340 --> 00:21.710 Now these days it can be used as a general purpose programming language. 00:21.710 --> 00:24.650 But that's not the case very often. 00:24.650 --> 00:28.130 It is still mostly used for web development. 00:28.160 --> 00:36.140 So PHP is open source, and this means that the PHP source code is publicly available for everyone to 00:36.170 --> 00:36.680 see. 00:36.680 --> 00:42.050 And you can also try and contribute to the PHP code. 00:42.770 --> 00:50.840 PHP is cross-platform, it runs on any operating system and it has an extensive built in library. 00:51.200 --> 00:53.330 Now the use cases of PHP. 00:53.330 --> 01:01.670 So as I said, it's mostly used to create dynamic web pages for the server side programming and also 01:01.670 --> 01:04.670 to create command line utilities. 01:04.940 --> 01:12.080 So to give you an example of a command line utility, there is a tool called deployer which is used 01:12.080 --> 01:16.880 to deploy PHP applications on remote Servers. 01:18.740 --> 01:23.150 So there are different aspects of creating the PHP programs. 01:23.150 --> 01:31.040 And actually you would have to understand them separately and some of them require more effort. 01:31.070 --> 01:35.690 Others are just something you learn along the way. 01:35.720 --> 01:42.140 So the first thing that will require your effort is learning the language itself. 01:42.140 --> 01:49.400 So you need to understand the syntax, the data types, all the control structures that control the 01:49.400 --> 01:51.140 flow of the programs. 01:51.230 --> 01:53.810 Then there are functions and classes. 01:53.810 --> 01:56.300 And how do you handle errors. 01:56.780 --> 01:58.010 Now the runtime. 01:58.010 --> 02:04.790 Well that's actually the environment in which the PHP programs you have created run. 02:04.790 --> 02:07.700 So that's the execution process. 02:07.700 --> 02:10.670 How are the PHP programs run? 02:10.700 --> 02:12.830 You will have to eventually understand that. 02:12.830 --> 02:15.950 How is the memory managed? 02:15.950 --> 02:18.650 How does the garbage collection works. 02:18.650 --> 02:25.280 So the runtime, that's a thing that will most probably come to you with experience. 02:25.280 --> 02:29.420 It's not something that you can just learn or read about. 02:29.450 --> 02:32.510 There are some things you should be aware of. 02:32.540 --> 02:39.890 But as I've said, the understanding of the runtime and the environment, this always comes with experience. 02:39.890 --> 02:44.900 The more programs you create and run, the more experience you will gain. 02:44.900 --> 02:53.210 So the last aspect of understanding the PHP programs is how do you actually work with all the features? 02:53.330 --> 03:01.820 So concepts like sessions, cookies, the file uploading, database interactions and handling web requests, 03:01.850 --> 03:09.770 those are not things that are unique to PHP, but you just need to understand how do you work with all 03:09.770 --> 03:17.480 those features using PHP as a language and PHP as a runtime or environment? 03:17.480 --> 03:20.000 So PHP has some specific ways. 03:20.000 --> 03:27.500 For example, sessions and cookies are handled using global variables and functions. 03:27.500 --> 03:29.270 The database interactions. 03:29.270 --> 03:35.870 Well, you might need to understand and use objects and classes for that, etc. etc.. 03:35.870 --> 03:45.080 So this is just understanding how you do all those things that are web development related using PHP 03:45.080 --> 03:47.150 as a language and environment.