1 00:00:03,710 --> 00:00:04,130 Okay. 2 00:00:04,130 --> 00:00:04,939 Let's continue. 3 00:00:04,939 --> 00:00:11,480 So if you remember we are working in the A building. 4 00:00:11,480 --> 00:00:17,510 We are building the back end of our basic, uh, level three application. 5 00:00:17,510 --> 00:00:22,520 And what we have done so far is the initial setup. 6 00:00:22,520 --> 00:00:29,600 We have created the virtual environment, we have installed the necessary packages, and then we have 7 00:00:29,600 --> 00:00:37,940 created the database, entered the credentials of the database in the dot m file and validate the data 8 00:00:37,940 --> 00:00:42,860 types of the uh, the credentials with pedantic. 9 00:00:43,190 --> 00:00:50,120 We are now going to create the table we are going to use in the database. 10 00:00:50,120 --> 00:00:59,780 So if you are not familiar with databases, um, don't worry about uh, about the concept of a database 11 00:00:59,780 --> 00:01:02,330 is it cannot be more simple. 12 00:01:02,930 --> 00:01:07,010 A database is just a collection of tables. 13 00:01:07,010 --> 00:01:14,600 And you already know a table because you have worked with spreadsheets and tables of columns and rows. 14 00:01:14,600 --> 00:01:15,080 So. 15 00:01:15,080 --> 00:01:20,720 So a database is just one table or a series of tables, you know. 16 00:01:20,720 --> 00:01:27,020 So in this case we are going to do the most simple type of a database, which is one database with just 17 00:01:27,020 --> 00:01:28,250 one table. 18 00:01:28,250 --> 00:01:28,880 Okay. 19 00:01:28,880 --> 00:01:31,550 So we already created the database. 20 00:01:31,550 --> 00:01:34,010 You remember when we did this. 21 00:01:34,160 --> 00:01:39,890 And we call the database my database in a very original manner. 22 00:01:39,890 --> 00:01:44,030 And now we are going to create the the table okay. 23 00:01:44,390 --> 00:01:49,280 So before that we check the local server. 24 00:01:49,340 --> 00:01:57,770 And uh right now well here we are providing you alternative ways to check the the server. 25 00:01:58,190 --> 00:01:59,480 Don't worry about this. 26 00:01:59,480 --> 00:02:02,510 Uh, now you can try this later. 27 00:02:02,510 --> 00:02:05,270 You know, these different approaches etc.. 28 00:02:05,270 --> 00:02:06,350 So now. 29 00:02:07,070 --> 00:02:08,840 After the initial check. 30 00:02:08,990 --> 00:02:13,040 Now close the app and set the database migrations. 31 00:02:13,040 --> 00:02:16,670 When we say database migration is okay, we are going to create a table. 32 00:02:16,670 --> 00:02:17,210 Okay? 33 00:02:17,420 --> 00:02:27,560 So in order to close the backend server you have to use control C okay. 34 00:02:27,560 --> 00:02:34,460 So you press the key control and the key C at the same time control C boom. 35 00:02:34,460 --> 00:02:39,140 And you will see that in the terminal the server stops okay. 36 00:02:39,800 --> 00:02:47,150 So now we are going to write a some lines that are going to sound like Chinese to you. 37 00:02:47,150 --> 00:02:48,020 Don't worry. 38 00:02:48,020 --> 00:02:52,250 The main purpose of all these lines is to create a table. 39 00:02:52,250 --> 00:02:52,640 Okay. 40 00:02:52,640 --> 00:02:56,060 So we are going to use a package called Alembic. 41 00:02:56,060 --> 00:03:04,100 And here you have a detailed explanation of what Alembic does, what this, uh, instruction does, 42 00:03:04,100 --> 00:03:07,370 etc. but right now I'm not going to stop there. 43 00:03:07,370 --> 00:03:13,820 We are just going back to our code editor. 44 00:03:13,940 --> 00:03:23,630 And when you when you, uh, execute this in your terminal, the application is going to create this 45 00:03:23,630 --> 00:03:26,090 folder for you, the Alembic folder. 46 00:03:26,090 --> 00:03:33,890 And you as you can see, this is just a version control a device to check. 47 00:03:33,890 --> 00:03:37,430 You know what we are doing with our database okay. 48 00:03:37,430 --> 00:03:39,530 So you will see what happens here later. 49 00:03:39,860 --> 00:03:40,760 So. 50 00:03:41,760 --> 00:03:51,210 A the first thing we are going to do is we are going to introduce this little, uh, change in the M 51 00:03:51,210 --> 00:03:56,100 file MP file that Alembic has created for us here. 52 00:03:56,310 --> 00:04:06,090 So in order for, uh, Alembic to use the credentials of the database, we are going to, uh, include. 53 00:04:06,780 --> 00:04:09,270 These line, these config set. 54 00:04:09,270 --> 00:04:12,990 What we are telling here is telling okay. 55 00:04:12,990 --> 00:04:18,089 So you are going to use and the the database. 56 00:04:18,089 --> 00:04:22,740 We have a with this database user and database password. 57 00:04:22,740 --> 00:04:28,110 So we are telling it in order to know what are the credentials of the database, you will have to go 58 00:04:28,110 --> 00:04:30,210 to the main m file okay. 59 00:04:30,600 --> 00:04:39,030 So for Alembic to know where is this m file we are going to enter here import OS. 60 00:04:39,030 --> 00:04:44,460 And then from dot m import load dot m which is what we are telling you here. 61 00:04:44,460 --> 00:04:45,330 And load them. 62 00:04:45,330 --> 00:04:53,460 So this line, this line, this line and this line, the 18 line, which is very long as you can see, 63 00:04:53,460 --> 00:05:01,740 are the ones that we are telling you that you have to add to the default m dot pi that Alembic has created 64 00:05:01,740 --> 00:05:04,980 inside of the Alembic a folder. 65 00:05:05,280 --> 00:05:06,270 Not important. 66 00:05:06,270 --> 00:05:07,500 This is not important. 67 00:05:07,500 --> 00:05:08,160 Okay. 68 00:05:09,110 --> 00:05:12,770 And so just, uh, stay with me and get the concept, and that's it. 69 00:05:12,770 --> 00:05:20,330 So now we are going to create the table of our database, and we are going to call this table todos. 70 00:05:20,360 --> 00:05:21,110 Okay. 71 00:05:21,110 --> 00:05:30,890 So in order to create a table in the database called todos you enter this command in your terminal okay. 72 00:05:31,760 --> 00:05:36,200 And you will see after doing that you do these operations. 73 00:05:36,200 --> 00:05:41,300 My recommendation is that first you pay attention to the video. 74 00:05:41,540 --> 00:05:46,100 Second, you download the code from GitHub. 75 00:05:46,340 --> 00:05:54,440 Third, you a repeat these operations with a copy and paste. 76 00:05:54,440 --> 00:06:02,660 So you open a new folder and you start copying and pasting, you know, and the things in this exact 77 00:06:02,660 --> 00:06:03,410 order. 78 00:06:03,410 --> 00:06:08,990 Whenever you find a problem, a doubt, a question, you go to chat, GPT four and the different sources 79 00:06:08,990 --> 00:06:10,190 you have, okay. 80 00:06:10,610 --> 00:06:16,100 And you do that the times you need in order to get familiar with the main concepts. 81 00:06:16,930 --> 00:06:26,350 So when you create a table, you will see that in Alembic versions you are going to have a file like 82 00:06:26,350 --> 00:06:27,130 this one. 83 00:06:27,130 --> 00:06:33,640 That is just a way to acknowledge that you have created the table. 84 00:06:33,640 --> 00:06:41,770 And in this, uh, file we are going to introduce a few changes which are basically these lines here. 85 00:06:41,770 --> 00:06:42,280 Okay. 86 00:06:42,280 --> 00:06:48,430 It's just telling, uh, that what are the contents we are going to have in the table. 87 00:06:48,430 --> 00:06:54,430 So in this case, our table, each of the items, each of the tasks is going to have a name. 88 00:06:54,940 --> 00:07:01,480 It's going to have an ID and it's going to have a completed A. 89 00:07:02,490 --> 00:07:03,000 Element. 90 00:07:03,000 --> 00:07:03,360 Right? 91 00:07:03,360 --> 00:07:05,970 So the computer is going to be what we call a boolean. 92 00:07:05,970 --> 00:07:09,450 So a complete it can be true or false okay. 93 00:07:09,660 --> 00:07:11,670 So not very important. 94 00:07:11,670 --> 00:07:15,000 We are just configuring the database okay. 95 00:07:15,000 --> 00:07:23,460 So in order to uh execute it uh the migration is just a way to like okay. 96 00:07:23,460 --> 00:07:23,790 Yes. 97 00:07:23,790 --> 00:07:26,190 You have created the database and the table. 98 00:07:26,190 --> 00:07:26,700 Excellent. 99 00:07:26,700 --> 00:07:33,780 So in order to execute this we are going to open Postgres from uh, the terminal. 100 00:07:33,780 --> 00:07:38,220 We are going to open our database inside of Postgres. 101 00:07:38,220 --> 00:07:45,870 So this is like opening Postgres in your in your computer and opening this database in progress in Postgres. 102 00:07:45,870 --> 00:07:51,420 And then you are going to create a database user with this name. 103 00:07:51,420 --> 00:07:55,650 And with this password you can choose the name and the password you want. 104 00:07:55,650 --> 00:07:58,170 This is the ones we are using in this example. 105 00:07:58,170 --> 00:08:06,210 And you are going to tell Postgres that this user has has all privilege so it can do whatever it wants 106 00:08:06,210 --> 00:08:06,900 okay. 107 00:08:07,510 --> 00:08:13,960 So we are telling here, give the user with this name user 12 all privilege. 108 00:08:13,960 --> 00:08:20,590 So all all the permissions in order to do whatever he wants to do in the database, name my database 109 00:08:20,590 --> 00:08:21,130 okay. 110 00:08:21,130 --> 00:08:25,450 And then this is going to close Postgres in your terminal okay. 111 00:08:25,450 --> 00:08:27,820 Here you have an alternative way of doing this. 112 00:08:27,820 --> 00:08:29,140 But don't worry about that. 113 00:08:29,860 --> 00:08:33,580 Then you go to Alembic dot. 114 00:08:34,460 --> 00:08:35,000 Ini. 115 00:08:35,900 --> 00:08:41,000 Okay, alembic ini and you edit the line. 116 00:08:42,230 --> 00:08:43,760 64. 117 00:08:43,789 --> 00:08:44,390 Okay. 118 00:08:44,390 --> 00:08:51,800 This line you are going to edit with your username, your password and the name of your database. 119 00:08:51,800 --> 00:08:57,080 And in this case a we know this is a local database okay. 120 00:08:57,960 --> 00:09:03,330 So you are also going to edit the the main dot m file. 121 00:09:03,390 --> 00:09:08,520 Uh, in order to include your right user and right password. 122 00:09:08,730 --> 00:09:09,330 Okay. 123 00:09:11,120 --> 00:09:16,700 So now we have a the new table in our database. 124 00:09:16,700 --> 00:09:18,020 And in order to. 125 00:09:19,280 --> 00:09:20,270 Close the deal. 126 00:09:20,270 --> 00:09:24,740 We are going to run this, uh, command in terminal. 127 00:09:24,740 --> 00:09:25,190 Okay. 128 00:09:25,190 --> 00:09:27,200 Alembic, upgrade head boom. 129 00:09:27,200 --> 00:09:27,950 That's it. 130 00:09:28,310 --> 00:09:35,360 Then if you want to check the status of your data database in your terminal, you do this. 131 00:09:35,360 --> 00:09:43,430 What this is doing is like, okay, open this database and show me everything that is in the table called 132 00:09:43,430 --> 00:09:44,090 todos. 133 00:09:44,090 --> 00:09:44,630 Okay. 134 00:09:44,630 --> 00:09:45,170 That's it. 135 00:09:45,170 --> 00:09:46,910 And then quit close. 136 00:09:46,910 --> 00:09:47,510 Okay. 137 00:09:47,510 --> 00:09:48,950 Not important. 138 00:09:49,310 --> 00:09:53,120 We give you some some more details about that here. 139 00:09:53,120 --> 00:10:01,460 We are also telling you that there is another file called database.py that has the object relational 140 00:10:01,460 --> 00:10:10,550 mapping, which is more additional information to uh let the application know about the, the the database 141 00:10:10,550 --> 00:10:13,040 and how to use the database, etc., etc.. 142 00:10:13,040 --> 00:10:13,970 Not important. 143 00:10:14,000 --> 00:10:14,690 Now. 144 00:10:14,690 --> 00:10:17,630 Models.py more the same. 145 00:10:18,440 --> 00:10:24,740 Uh, we are just, you know, configuring our database or go here in detail later. 146 00:10:24,740 --> 00:10:26,420 Now it's not important. 147 00:10:26,510 --> 00:10:36,440 What is important now is the most important file of the backend, uh, application, which is this Crud. 148 00:10:36,440 --> 00:10:45,650 In this Crud, we are going to write the Python functions to, uh, perform the main operations of our 149 00:10:45,650 --> 00:10:46,520 application. 150 00:10:46,520 --> 00:10:47,330 Okay. 151 00:10:48,500 --> 00:10:56,690 So here we are going to explain you in super detail everything that you see here. 152 00:10:56,960 --> 00:10:57,500 Okay. 153 00:10:57,500 --> 00:11:06,200 So every little piece of this code is super explained in this notebook okay. 154 00:11:06,200 --> 00:11:07,160 Super explain. 155 00:11:07,700 --> 00:11:08,210 Okay. 156 00:11:08,810 --> 00:11:15,230 Then we are explaining you the things you are going to do in the router. 157 00:11:15,350 --> 00:11:24,140 So the router is what is going to convert our Python application in a web application. 158 00:11:24,140 --> 00:11:31,040 Because the router manages the routes, the routes of the web applications, the different pages and 159 00:11:31,040 --> 00:11:32,030 the different actions. 160 00:11:32,030 --> 00:11:32,480 Okay. 161 00:11:32,480 --> 00:11:39,620 So all this code you have here is explained in detail in the notebook okay. 162 00:11:40,840 --> 00:11:50,530 So once you create the to DOS router, you will need to come back to the main file and uncomment this 163 00:11:50,530 --> 00:11:52,630 line and this line. 164 00:11:52,630 --> 00:11:54,070 Right now they are uncommented. 165 00:11:54,070 --> 00:11:55,060 They are okay. 166 00:11:55,060 --> 00:12:00,850 But before I told you to enter here a pound sign and the same here. 167 00:12:00,850 --> 00:12:08,410 Okay, now we have the router so we can clear the pound sign there and there okay. 168 00:12:08,890 --> 00:12:17,380 Then you can run the server again from the terminal with the same, uh, instruction. 169 00:12:17,800 --> 00:12:21,730 And you can you don't have a front end. 170 00:12:22,330 --> 00:12:24,430 So you cannot. 171 00:12:24,430 --> 00:12:33,280 Without a front end, the user cannot enter a task here or delete a task or update a task, but you 172 00:12:33,280 --> 00:12:39,340 from the back end using the terminal can perform this operation. 173 00:12:39,340 --> 00:12:48,100 So here you have how to try your graph application from your terminal. 174 00:12:48,100 --> 00:12:52,870 So this is what you need to write to create one. 175 00:12:52,870 --> 00:13:01,420 To do tasks from your terminal and to display, to update, to delete, etc., etc.. 176 00:13:01,870 --> 00:13:12,220 Okay, so right now you have a very basic back end of a Crud application. 177 00:13:13,900 --> 00:13:17,020 I know a lot of new things. 178 00:13:17,020 --> 00:13:18,280 Uh, here. 179 00:13:18,280 --> 00:13:21,700 Uh, do not feel overwhelmed. 180 00:13:21,760 --> 00:13:23,830 Just stay with me. 181 00:13:23,830 --> 00:13:24,880 Bear with me. 182 00:13:24,880 --> 00:13:34,090 Keep the main concepts and start repeating this subsection in the way I have recommended until you start 183 00:13:34,090 --> 00:13:35,740 feeling comfortable. 184 00:13:36,630 --> 00:13:41,250 Whenever you have a problem, whenever you have a question, whenever you have an error, while you 185 00:13:41,250 --> 00:13:43,860 are repeating this exercise, go to chat. 186 00:13:43,860 --> 00:13:46,830 GPT four and the other sources we have recommended. 187 00:13:46,830 --> 00:13:50,460 Okay, so download the code from GitHub. 188 00:13:50,790 --> 00:14:00,660 First, repeat the process once in your computer and then twice and third time, etc. etc. don't bother. 189 00:14:00,660 --> 00:14:06,870 Don't don't worry about creating many, uh, different folders for many different applications. 190 00:14:06,930 --> 00:14:13,410 Uh, just repeat this until you feel comfortable and whenever you find a problem, just investigate 191 00:14:13,410 --> 00:14:14,520 about it, okay? 192 00:14:14,520 --> 00:14:24,510 And once you feel a comfortable, then we go to create the front end of our application. 193 00:14:24,510 --> 00:14:24,990 Okay. 194 00:14:24,990 --> 00:14:27,420 It will be in the notebook. 195 00:14:28,960 --> 00:14:34,240 It will be what we call the part two, which is here. 196 00:14:34,330 --> 00:14:35,020 Okay. 197 00:14:35,020 --> 00:14:40,630 So in the next subsection we are going to create the front end of the application.