1 00:00:00,180 --> 00:00:00,800 Play everybody. 2 00:00:00,810 --> 00:00:07,020 So now it's time to override the uncreate method that we inherit from this is to light up and help her 3 00:00:07,230 --> 00:00:07,900 class. 4 00:00:08,130 --> 00:00:13,560 So if I hold on to comment on my keyboard and then click on a school like an helper here you can see 5 00:00:13,560 --> 00:00:15,650 that it is actually an abstract class. 6 00:00:15,690 --> 00:00:22,950 So what is an abstract class an abstract class is a class that contains one or more accurately abstract 7 00:00:22,950 --> 00:00:23,660 methods. 8 00:00:23,670 --> 00:00:28,980 So what is and what is an abstract method and abstract and if it is an effort that does not have and 9 00:00:28,980 --> 00:00:30,220 then an implementation. 10 00:00:30,420 --> 00:00:33,620 So let me search for the uncreate method here. 11 00:00:34,140 --> 00:00:36,830 Let me actually show you the uncreate method here. 12 00:00:36,870 --> 00:00:38,380 So here it is the uncreate method. 13 00:00:38,400 --> 00:00:39,090 Right. 14 00:00:39,090 --> 00:00:42,150 You can see that it is actually an abstract method. 15 00:00:42,170 --> 00:00:48,590 This if it does if it accepts an argument of type as you like database and it does not have any implementations. 16 00:00:48,720 --> 00:00:52,580 So let's go to the data handler class after the constructor. 17 00:00:52,590 --> 00:00:54,710 I can just type in and create. 18 00:00:54,720 --> 00:00:58,620 So now I can pro-white an implementation for this. 19 00:00:58,650 --> 00:00:59,930 Uncreate method. 20 00:01:00,150 --> 00:01:03,660 So remember this uncreate method is an abstract method. 21 00:01:03,690 --> 00:01:06,070 Inside this school I often helper class. 22 00:01:06,120 --> 00:01:06,660 Right. 23 00:01:06,870 --> 00:01:12,530 So let's go inside the curly braces of this uncreate Mefford and let's actually put our own logic here. 24 00:01:12,630 --> 00:01:14,980 So why do we have to implement this class. 25 00:01:15,090 --> 00:01:24,390 Because if we want to actually create our database our school database we must put our codes the database 26 00:01:24,390 --> 00:01:28,020 creation cost actually inside this uncreate method. 27 00:01:28,050 --> 00:01:31,350 So let's go inside this Meffert and we can now we can say. 28 00:01:31,530 --> 00:01:36,960 So inside this uncreate Meffert let's create a variable of types 3 in the name of this variable is going 29 00:01:36,960 --> 00:01:41,400 to be create database s u l assignment operator. 30 00:01:41,400 --> 00:01:48,120 Here we need to put two quotes here and we need to put the L command in order to create an SD like database 31 00:01:48,270 --> 00:01:49,290 for our application. 32 00:01:49,290 --> 00:01:50,620 So it is very important. 33 00:01:50,820 --> 00:01:56,940 Just type in here create a space table space. 34 00:01:56,940 --> 00:02:02,730 This is really important that you put our space here right and then put on a concatenation operator 35 00:02:02,730 --> 00:02:06,760 plus operator here and here we need to put the table name. 36 00:02:06,810 --> 00:02:11,380 So we created a constant here for this table in a martial arts table. 37 00:02:11,400 --> 00:02:14,620 So just step in here martial arts table right. 38 00:02:14,640 --> 00:02:22,800 Plus So here we must specify the rows of our table so just put two coats here and then poods actually 39 00:02:22,820 --> 00:02:28,300 open in prentices here space and just put up a concatenation operator here. 40 00:02:28,320 --> 00:02:29,890 After these coats. 41 00:02:29,910 --> 00:02:35,260 So the first actually the first row is going to be for the key. 42 00:02:35,280 --> 00:02:45,210 So just type in here Id key with capital key right now that we have this ID key Let's put actually another 43 00:02:45,210 --> 00:02:50,460 concatenation operator Plus space two quotes space. 44 00:02:50,700 --> 00:02:52,970 So Id keep plus actually. 45 00:02:52,980 --> 00:02:58,550 And then here we have these two coats here and then put space inside these coats. 46 00:02:58,700 --> 00:03:02,850 And now we need to specify the type of this are the key. 47 00:03:03,050 --> 00:03:03,670 OK. 48 00:03:03,690 --> 00:03:05,160 It is going to be of the interior right. 49 00:03:05,160 --> 00:03:12,960 The idea is going to be off that I so I can say integer primary key primary key auto increment auto 50 00:03:13,500 --> 00:03:14,250 increment. 51 00:03:14,250 --> 00:03:21,570 So when I say integer primary key auto increment it means that the value of the ID of each marshal is 52 00:03:21,570 --> 00:03:27,900 going to be of that integer primary key auto increment means that it is going to be actually incremented 53 00:03:27,930 --> 00:03:33,390 automatically the ID is going to be specified for each marginal object automatically. 54 00:03:33,390 --> 00:03:36,430 We do not have to worry about this idea anymore. 55 00:03:36,480 --> 00:03:39,810 When I say integer primary key auto increment. 56 00:03:40,030 --> 00:03:44,380 OK so for not just here this is the type of this ID. 57 00:03:44,430 --> 00:03:44,850 Right. 58 00:03:44,850 --> 00:03:50,800 This is the type of this ID you need to specify this search and actually row. 59 00:03:50,820 --> 00:03:53,610 So let me create a new line here. 60 00:03:53,670 --> 00:03:57,920 So let me just create a new line here so that you can see these values better. 61 00:03:58,140 --> 00:04:02,680 So first you say create table space marshal or table plus. 62 00:04:02,700 --> 00:04:04,100 And then we need to specify the rows. 63 00:04:04,100 --> 00:04:05,430 So this is the first throw. 64 00:04:05,700 --> 00:04:11,870 I put up a and in practice this year space the key plus and I put two coats here. 65 00:04:11,910 --> 00:04:13,320 I put up space here. 66 00:04:13,320 --> 00:04:15,580 Integer primary key auto increment. 67 00:04:15,600 --> 00:04:20,040 So now after this is called I put another concatenation operator. 68 00:04:20,130 --> 00:04:26,990 Let's create a new line here and I put two coats here and here I need to specify the second row. 69 00:04:27,090 --> 00:04:28,590 So I just put a comma here. 70 00:04:28,590 --> 00:04:35,760 This is really important comma space and after these codes I put a plus operator here and then I'm going 71 00:04:35,760 --> 00:04:40,360 to refer to the second row name which is going to be this one Name Key. 72 00:04:40,470 --> 00:04:43,770 So I can see Name Key plus. 73 00:04:43,980 --> 00:04:50,100 And here I must specify that data type of this name which is of type strange but in S2 let me say it 74 00:04:50,100 --> 00:04:51,720 is of type text. 75 00:04:51,780 --> 00:04:56,110 So I just put two quotes here space and here I want to say text. 76 00:04:56,130 --> 00:04:58,030 Right this means that this is of type. 77 00:04:58,080 --> 00:04:58,970 Strange. 78 00:04:59,040 --> 00:05:07,210 So after this code I put a plus OPERATOR Two quotes comma space and then after this goes again I put 79 00:05:07,210 --> 00:05:08,580 another plus operator. 80 00:05:08,830 --> 00:05:13,220 So now we need to specify the other key which is the price key. 81 00:05:13,330 --> 00:05:16,570 So I can't say price key right. 82 00:05:16,870 --> 00:05:19,950 And then he had a full A-plus OPERATOR Two coats. 83 00:05:19,960 --> 00:05:25,360 And here I put our space and now I need to specify that data type of this. 84 00:05:25,370 --> 00:05:27,780 Press TV is going to be of type float. 85 00:05:27,970 --> 00:05:31,130 So data in a school like we say that it is a big deal. 86 00:05:31,150 --> 00:05:34,600 So I can't say really all right. 87 00:05:35,090 --> 00:05:37,730 And then here I put another plus. 88 00:05:37,730 --> 00:05:38,880 Operator. 89 00:05:39,170 --> 00:05:40,640 Let me create a new line. 90 00:05:40,820 --> 00:05:42,760 So now we need to specify the final row. 91 00:05:42,830 --> 00:05:47,830 So again just put two coats here comma space plus. 92 00:05:47,900 --> 00:05:54,800 So the final row is going to be the color key so color key plus two code so it is going to be of type 93 00:05:54,800 --> 00:05:55,250 string. 94 00:05:55,250 --> 00:06:05,180 So just type in here text and now after this code is put another plus operator to coats space and just 95 00:06:05,210 --> 00:06:10,230 close this plant this is the end in Prentice's here and finally put a semicolon here. 96 00:06:10,280 --> 00:06:14,460 So this is our Eski will come on right create table. 97 00:06:14,660 --> 00:06:21,350 And this is the name of it of the table martial arts table plus I put actually two coats here and I 98 00:06:21,350 --> 00:06:24,290 put this open in parenthesis here plus ID key. 99 00:06:24,290 --> 00:06:26,220 So this is the first row plus. 100 00:06:26,240 --> 00:06:31,400 And here inside the coats I put a space first and then we specify the data type of this ID which is 101 00:06:31,400 --> 00:06:33,990 integer primary key also increment plus. 102 00:06:34,040 --> 00:06:38,780 And then I put two coats come on space plus add and this is the second row which is going to be the 103 00:06:38,780 --> 00:06:41,020 name key plus space. 104 00:06:41,060 --> 00:06:45,460 And here you can see in say the course space text plus coats. 105 00:06:45,500 --> 00:06:51,310 And here we have a comma space plus Kreisky plus two coats. 106 00:06:51,350 --> 00:06:57,580 Space real plus two coats come on space plus color key plus. 107 00:06:57,680 --> 00:06:59,920 And here this is that data type of this color. 108 00:06:59,930 --> 00:07:01,450 So I just put two codes. 109 00:07:01,490 --> 00:07:02,560 Space takes. 110 00:07:02,660 --> 00:07:09,080 And finally I put another concatenation operator and I put two coats and I put space here and I close 111 00:07:09,140 --> 00:07:11,300 this plant is this semi-colon. 112 00:07:11,330 --> 00:07:16,200 So this is our rescue l.com and this is very important that it must be like this here. 113 00:07:16,460 --> 00:07:21,920 Otherwise our leader when we want to actually just referred to our database or application is going 114 00:07:21,920 --> 00:07:22,420 to crash. 115 00:07:22,430 --> 00:07:28,250 If you just type it in a runway for example if you forget to put a comma here your application is going 116 00:07:28,250 --> 00:07:29,210 to crash. 117 00:07:29,210 --> 00:07:29,660 Right. 118 00:07:29,660 --> 00:07:34,400 It is very important so just make sure that your command is the same as mine here. 119 00:07:34,410 --> 00:07:40,470 This is how you create a table if you want to use as you are as you like in order to save your data 120 00:07:40,470 --> 00:07:42,430 or to your database. 121 00:07:42,500 --> 00:07:43,210 So that's it. 122 00:07:43,220 --> 00:07:48,800 So here you can see that we have this argument of type as you are Escuela database that we actually 123 00:07:48,800 --> 00:07:50,340 get from this uncreate method. 124 00:07:50,600 --> 00:07:53,790 So we have a reference to the actual database right. 125 00:07:53,810 --> 00:08:01,110 So I can say D-B that execute as well just call this in effect and B and here we just need to pass there 126 00:08:01,240 --> 00:08:03,130 as you l.com and which is of type string. 127 00:08:03,200 --> 00:08:07,700 So if we have this come on here create a database Escurial that's it. 128 00:08:07,700 --> 00:08:12,780 So it's going to create that database for us by using this as tool here. 129 00:08:12,880 --> 00:08:13,780 This will come in. 130 00:08:13,820 --> 00:08:19,050 So now after this uncreate Smurfette I am going to actually create another method. 131 00:08:19,160 --> 00:08:23,680 So here we must override and another actually method here. 132 00:08:23,720 --> 00:08:27,260 And this is called an upgrade on upgrade. 133 00:08:27,290 --> 00:08:28,450 So through this method. 134 00:08:28,700 --> 00:08:36,600 So this method is going to be actually called when our current database religion is updated. 135 00:08:36,710 --> 00:08:39,530 This is because this is actually the first version of our database. 136 00:08:39,530 --> 00:08:44,360 This is the Smurfette is not going to be called but later on for example when you want to update your 137 00:08:44,360 --> 00:08:45,530 database. 138 00:08:45,530 --> 00:08:48,580 And when you want to upgrade your database this method is going to be called. 139 00:08:48,590 --> 00:08:50,580 So let's put some logic here. 140 00:08:50,600 --> 00:08:54,960 So here I can see D.V. that execute as well. 141 00:08:55,100 --> 00:08:59,520 And inside Apprentice's just put two double quotes at inside the code. 142 00:08:59,540 --> 00:09:00,320 Just type in here. 143 00:09:00,320 --> 00:09:06,190 Drop table if exists I then put my space here. 144 00:09:06,390 --> 00:09:11,640 So now after these courts just put A-plus plus operator and then referred to the martial arts table. 145 00:09:11,910 --> 00:09:12,540 Right. 146 00:09:12,780 --> 00:09:18,510 If you want to for example upgrade our database version it's going to drop the current version of the 147 00:09:18,510 --> 00:09:22,340 database and then we are going to call the uncreate method again. 148 00:09:22,590 --> 00:09:26,210 So uncreate So we actually overlay these uncreate here right. 149 00:09:26,220 --> 00:09:30,020 So we need to pass a value of that as soon as you light it up. 150 00:09:30,030 --> 00:09:32,040 So we get that from this method. 151 00:09:32,080 --> 00:09:33,950 DB Right. 152 00:09:34,050 --> 00:09:34,730 So that's it. 153 00:09:34,740 --> 00:09:40,950 These are the methods that are necessary in order to if you want to actually work with the light help 154 00:09:41,250 --> 00:09:42,770 open helper class. 155 00:09:42,960 --> 00:09:45,010 We must override these two methods. 156 00:09:45,020 --> 00:09:50,040 So now you can see that we have no errors inside this class in the next story or we're going to go ahead 157 00:09:50,070 --> 00:09:57,960 and we're going to actually create some Misfit's in order to add a modular object to the database in 158 00:09:57,960 --> 00:10:00,200 order to delete almost an object from the database. 159 00:10:00,210 --> 00:10:05,030 And another method in order to update the current marshal or object. 160 00:10:05,060 --> 00:10:06,510 So thank you very much for watching. 161 00:10:06,510 --> 00:10:07,830 And I see in the next tutorial.