WEBVTT 00:05.230 --> 00:07.060 I ever will come back. 00:07.060 --> 00:13.270 So and this is what we are going to be discussing what exactly is a database and why we need a database 00:13.360 --> 00:14.850 in our web applications. 00:14.860 --> 00:18.230 Why do we need to add it into our API or in general anything. 00:18.250 --> 00:18.810 Right. 00:19.060 --> 00:21.670 And so yes let's get right into it. 00:21.670 --> 00:25.160 So let's just define what exactly is a database. 00:25.230 --> 00:29.930 A database is just a structured set of data held in the computer. 00:29.950 --> 00:35.630 So it's you can think of it as a collection of data that is stored inside the computer. 00:35.650 --> 00:38.240 So why exactly is this useful. 00:38.440 --> 00:43.900 If you think about all the computers that we've been or all the web applications or API that we've been 00:44.080 --> 00:51.430 developing so far we basically have a server over here so I'll draw a server and then inside this server 00:51.430 --> 00:58.940 I have my application running and then the user is basically from his own browsers or lots of allright 00:58.990 --> 01:06.130 browsers and lots of users have browser one browser to all the way to lots of brothers and every one 01:06.130 --> 01:13.480 of them makes an HDTV request a miser right to request a specific page so HTP page. 01:13.540 --> 01:14.090 Right. 01:14.350 --> 01:21.180 But if you think about it this this mechanism over a year is only good for a few for a few cases right. 01:21.400 --> 01:27.940 Well if you think about any of the pages that you interact with usually not only that you just request 01:27.940 --> 01:30.470 to see some information you get it a little. 01:30.520 --> 01:37.060 Let's think about Facebook for example Facebook and Facebook you have to log in into your account and 01:37.060 --> 01:38.550 then you can post stuff. 01:38.560 --> 01:42.270 And if you close Facebook then this stuff is not gone right. 01:42.270 --> 01:46.620 You would expect that your posts would remain there until you delete them right. 01:46.740 --> 01:50.040 Or you hope at least that they would lead them right. 01:50.080 --> 01:51.990 So what exactly. 01:52.040 --> 01:55.180 How can we achieve this with what we know so far. 01:55.180 --> 01:58.340 So what we know so far is just a one way thing. 01:58.340 --> 01:59.770 Right we have a request. 01:59.830 --> 02:06.790 So we have a request and then this request is hey get or post this information to the server and the 02:06.790 --> 02:12.280 server has to do some computation over here and then reply me just the response right. 02:12.280 --> 02:18.160 And that's usually 200 and then maybe it's a J song file with some information for the browser. 02:18.160 --> 02:23.340 As we've discussed before now what about if this user wants to sign up. 02:23.470 --> 02:29.510 Well how do I know that this is the username and the correct user name and password for this user. 02:29.620 --> 02:32.390 Well they use it let's say the user tries to sign up. 02:32.530 --> 02:36.830 So he sends his information username and password over the Internet to me. 02:37.060 --> 02:41.080 And so now I have this username and password right. 02:41.130 --> 02:46.570 And I have to do some computation and tell him OK you're registered now but let's say he closes the 02:46.570 --> 02:48.610 browser and that opens it again. 02:48.610 --> 02:51.850 How do I know that this is exactly the same person right. 02:51.970 --> 02:58.900 If I want to know that well the only way I can know this is if I knew his username and I know his password. 02:59.050 --> 03:04.540 So if I don't know these two things if I don't know his username I don't know his password then I can 03:04.540 --> 03:10.300 verify right because this person might tell me hey I don't know if this username is cold. 03:10.480 --> 03:13.490 For example in his password is 1 2 3. 03:13.480 --> 03:18.670 So hopefully your password is not 1 2 3 but if this is the username and password then this guy might 03:18.670 --> 03:19.970 tell me hey I'm OK. 03:20.070 --> 03:22.280 Right a lot of me instead of this guy. 03:22.420 --> 03:28.770 So the only way we can verify this is if I store the username and password of this user somewhere. 03:28.990 --> 03:32.590 And that's exactly the idea of a database database. 03:32.620 --> 03:34.430 We're to put a database here. 03:34.510 --> 03:38.320 The whole idea of a database is to store these types of information. 03:38.380 --> 03:42.260 So a database you can think of it as a big document. 03:42.260 --> 03:42.490 OK. 03:42.520 --> 03:46.790 And it's full of fros row on row to all the way OK. 03:46.840 --> 03:52.650 Lots of rows and then each of these rows might have each of these customers might have a different idea. 03:52.660 --> 03:53.190 Right. 03:53.320 --> 03:58.120 And then a different username and then a different password. 03:58.360 --> 03:58.850 Right. 03:58.990 --> 04:01.780 Hopefully you don't store the password in plain text editor. 04:01.790 --> 04:09.220 God talk about that in later videos but this is the password or what they commonly call in in development 04:09.310 --> 04:13.410 the hashed password and so on. 04:13.450 --> 04:17.790 Lots of fields for example date of birth maybe and so on. 04:17.800 --> 04:23.590 So you'd have a book or a document that looks like this and then you whenever a new user or whenever 04:23.650 --> 04:29.290 a new user sends you that information from the registration form you would get this information and 04:29.290 --> 04:35.380 then you say OK I have a user name so I'm going to add a new row into my database so you communicate 04:35.380 --> 04:41.290 with the database while you're computing and then you say OK I'm going to put the ID the next ID's for 04:41.290 --> 04:48.520 example 3 and then I'm going to put the user name and his password so I'll just put some stars over 04:48.520 --> 04:50.450 here to denote the password. 04:50.590 --> 04:56.230 And then the date of birth and fill all this information into your database and then once you're happy 04:56.230 --> 04:58.010 with this once this information is. 04:58.150 --> 05:04.030 So once your database tells you OK right once your database tells you everything the story to hear then 05:04.030 --> 05:08.920 you can information and say hey you know what I've registered to you. 05:08.970 --> 05:14.610 So now the next time someone wants to log in if this guy is a sneaky guy and he tries to log in he tells 05:14.610 --> 05:21.720 you Hey I'm a and my password is you know is three to one for example that you and you would he would 05:21.720 --> 05:24.040 send you this information by a post. 05:24.180 --> 05:30.820 And then he would tell the database Hey do you have any user which which is called a and has this password. 05:30.870 --> 05:35.460 So you look here and then you would notice that this is not the password right because the original 05:35.460 --> 05:37.310 password is 1 2 3. 05:37.380 --> 05:42.060 So you add the database with all your ah I don't have this username and password. 05:42.060 --> 05:43.640 So you would reply this user. 05:43.790 --> 05:46.080 I'm sorry I cannot lie you end right. 05:46.080 --> 05:48.590 This is an invalid password. 05:48.840 --> 05:54.250 So in other words a database is just a document to keep track of things. 05:54.270 --> 05:58.980 Once the the the whole request and response is gone right. 05:58.980 --> 06:06.080 Because if you only rely on the response and the your request and the response then you can how long 06:06.270 --> 06:08.520 you lose a lot of information right. 06:08.520 --> 06:14.000 For example Facebook wouldn't be able if you'd get the post and then they don't store it somewhere. 06:14.000 --> 06:16.340 Then there's no way that this brand. 06:16.380 --> 06:20.130 Next time you log in then the Facebook will tell you sorry I did. 06:20.130 --> 06:21.340 I don't have a database. 06:21.340 --> 06:23.130 I didn't store it right. 06:23.160 --> 06:24.550 So so for all that. 06:24.590 --> 06:32.100 Although although AP is that we've been doing we have done only one API right support slash and slash 06:32.100 --> 06:37.380 divide or division and slash multiply and slash subtract right. 06:37.440 --> 06:43.270 And if you notice something about this API is that it doesn't need any information to be short and that 06:43.430 --> 06:47.400 the reason is well we don't have any. 06:47.420 --> 06:52.860 Well we don't we don't need to store anything right because the operations that these API were doing 06:52.860 --> 06:59.430 was basically just add divide multiply and subtract so they don't need any information they don't need 06:59.460 --> 07:01.240 any username password right. 07:01.380 --> 07:06.040 And your user who sends his request we can automatically handle his request right. 07:06.300 --> 07:07.770 But usually that's not the case. 07:07.770 --> 07:14.100 For example if your API is paid then you might want to store here how much how much money this user 07:14.100 --> 07:15.120 has in his credit. 07:15.120 --> 07:15.420 Right. 07:15.450 --> 07:23.730 Let's say you give this user $100 right and he tell him if you want more more to do more API calls then 07:23.730 --> 07:24.850 you need to pay more. 07:25.020 --> 07:31.640 Well this user might might if you if he wants to log in then he has to have his own username and password 07:31.640 --> 07:31.790 right. 07:31.790 --> 07:36.860 To make this call and to subtract a little bit from his money for every call. 07:37.170 --> 07:42.090 So that's the idea of a database really is that we need to store a lot of information or we need to 07:42.270 --> 07:48.900 store information about the customer mainly the customers and all the information about their usage 07:48.930 --> 07:49.680 of the service. 07:49.680 --> 07:52.570 For example some people might even have a difference. 07:52.620 --> 07:58.920 Michael this database one so people might have even a second database so let's call it a database too. 07:59.130 --> 08:05.030 And that inside this database do they would store different things for example customer I.D.. 08:05.250 --> 08:14.220 Customer ID and then they would store the type of API calls or API call Vasos little bits smaller spacier 08:14.730 --> 08:22.080 and then you would say for example that user id 3 sent me an API call as Slash had at this date for 08:22.080 --> 08:22.800 example. 08:23.010 --> 08:25.980 And then he called slash multiply right. 08:26.040 --> 08:31.900 So some people might want to know OK what's the most famous API call that that the people are calling 08:31.900 --> 08:33.100 in my API right. 08:33.120 --> 08:35.580 And and for that you have to store it in the database. 08:35.580 --> 08:35.990 Right. 08:36.150 --> 08:42.990 So from now on whenever we think about we want to store something that the user sends us or that we 08:42.990 --> 08:43.690 calculate. 08:43.680 --> 08:49.710 So for example think about maybe a web application that does something that takes so much resources 08:49.710 --> 08:49.950 right. 08:49.950 --> 08:56.360 For example it has to compute the matrix multiplication of two huge matrices. 08:56.760 --> 09:02.460 So instead of having to calculate every time at crunch time we can just store it in a database and then 09:02.460 --> 09:05.400 one once we need it we can access it from the database. 09:05.400 --> 09:06.000 Right. 09:06.060 --> 09:13.410 So the whole idea is to store to be able to store many things like customer information customer usage 09:13.410 --> 09:19.080 of these things or even information that you might need right for for your application to run. 09:19.080 --> 09:23.580 For example you want to keep a counter of how many users are visiting your Web site. 09:23.580 --> 09:28.180 So every time you get a hit then you increase the counter in the database by one. 09:28.320 --> 09:33.480 So for example you got a request plus one and then you get a request again you see how many users you 09:33.480 --> 09:38.790 have and then you add one two plus two now and then you get another eques you see blustery so you add 09:39.130 --> 09:40.590 them plus three and so on. 09:40.770 --> 09:44.730 So anything that you want to store for a long term right. 09:44.730 --> 09:46.590 Not just during the computation. 09:46.590 --> 09:46.730 Right. 09:46.730 --> 09:52.290 So not anywhere or something that you want to store is usually stored in a database. 09:52.290 --> 09:54.660 So there's two types of database. 09:54.690 --> 09:57.590 There is mice or sequel. 09:57.650 --> 09:58.960 No and No. 09:58.980 --> 10:06.940 SIEGEL OK so we're using a no single database for our project it because it's much easier to deal with 10:07.130 --> 10:07.810 Jasons. 10:07.910 --> 10:10.790 So we will be using a no secret code. 10:10.820 --> 10:16.600 Mungo D-B So this one that you might have heard this in the is a famous database now and it uses the 10:16.600 --> 10:17.580 no sequel. 10:17.680 --> 10:21.810 So some examples of sequel databases might be my sequel right. 10:21.820 --> 10:25.110 You might have heard of my sequel This is the oldest type of data. 10:25.170 --> 10:28.950 A lot of the all this but it's very common in the industry to be used. 10:29.110 --> 10:36.070 But also Lovegood maybe starting to use a lot more because it's very fast almost as well not not the 10:36.070 --> 10:40.010 same speed as my sequel but it's very very comparable. 10:40.120 --> 10:46.510 And you know the Mongo baby or no sequel in general has a lot more advantages than sequel which will 10:46.510 --> 10:49.470 discuss it briefly and in a future. 10:49.930 --> 10:56.200 So hopefully this makes sense right where we're going to be you'd be using and no sequel database and 10:56.200 --> 10:58.950 this database is called Mongo NDB. 10:58.960 --> 11:05.020 Right so we're going to be explaining how to use more goodi be and that will use if you want like a 11:05.110 --> 11:11.290 heads up of what we're going to be use and we're going to use this Mongo D-B to make out an application 11:11.290 --> 11:14.000 to improve our application of slash add. 11:14.140 --> 11:19.540 But this time we're only going to allow users to use our API five times. 11:19.560 --> 11:20.100 Right. 11:20.350 --> 11:26.440 And then they have to also supplement apart from x and y they have to supplement also their username 11:26.680 --> 11:27.690 and password. 11:27.760 --> 11:33.110 OK so they have to supply both of these things before they can use the API. 11:33.220 --> 11:39.090 So if the user and if if some user uses the API more than five times then I'm going to reject it. 11:39.090 --> 11:43.080 I'm going to tell him hey you have to pay to go to another time five times. 11:43.090 --> 11:49.980 So hopefully this user infirm user information and password we're going to store in a Magdi database. 11:50.170 --> 11:58.420 And so we can keep track of how many and maybe also how many API calls this user has done. 11:58.450 --> 12:04.510 So for you we can keep track of how many calls that this user has done in the past. 12:04.510 --> 12:05.730 For example one month. 12:05.740 --> 12:06.790 Right. 12:06.820 --> 12:08.290 So yeah. 12:08.430 --> 12:13.220 We'll stop here and in the next video we're going to talk more about this so until the next video at 12:13.300 --> 12:13.810 decoding.