1 00:00:00,930 --> 00:00:02,700 Welcome back. 2 00:00:03,270 --> 00:00:05,160 We have the to do been. 3 00:00:06,300 --> 00:00:09,300 Let's say we have a to do table in the database. 4 00:00:09,840 --> 00:00:14,490 JPA allows us to map your bean to the database. 5 00:00:15,690 --> 00:00:21,150 The way you can do that is by adding a simple annotation called Add Entity. 6 00:00:22,500 --> 00:00:31,680 If you say the To-Do is an entity, it means that this bean is mapped to a database table. 7 00:00:31,740 --> 00:00:35,490 Let's just add in entity control one input. 8 00:00:36,700 --> 00:00:38,980 Jakarta persistence. 9 00:00:39,400 --> 00:00:43,240 So you'd see that Jakarta persistence not entities imported in. 10 00:00:45,490 --> 00:00:51,200 Whenever you have an entity, you would also need to have ID. 11 00:00:51,340 --> 00:00:53,230 So you need to define primary key. 12 00:00:54,300 --> 00:00:57,660 I'll add in at ID and say control one. 13 00:00:58,650 --> 00:00:59,210 Import it. 14 00:00:59,220 --> 00:01:00,810 Jakarta Persistence. 15 00:01:01,020 --> 00:01:01,800 Let's do that. 16 00:01:01,800 --> 00:01:04,680 And we would also want to generate this using a sequence. 17 00:01:04,690 --> 00:01:07,050 So I'll say generated value. 18 00:01:08,150 --> 00:01:10,280 So think about what we are doing in here. 19 00:01:10,610 --> 00:01:16,100 We are mapping to do been this been to a table in the database. 20 00:01:16,550 --> 00:01:19,310 That's what entities allow you to do. 21 00:01:19,790 --> 00:01:23,150 It allows you to map a bean to a database table. 22 00:01:23,180 --> 00:01:30,590 One of the magic of Springboard auto configuration is that if it sees any entities, then it would automatically 23 00:01:30,590 --> 00:01:32,990 start creating tables in H2. 24 00:01:33,560 --> 00:01:38,030 If you look at our Android XML, we have two database in here. 25 00:01:38,810 --> 00:01:40,310 So let's see where it is. 26 00:01:41,660 --> 00:01:45,980 If you look at Palm that XML, we have a database in here. 27 00:01:46,430 --> 00:01:53,150 And as soon as Springboard sees history database, what it does is it would start pre configuring it. 28 00:01:53,240 --> 00:01:57,770 One of the pre configuring steps is if it sees any entities. 29 00:01:57,800 --> 00:02:03,080 If it sees any entities like this, it would directly start creating tables for them. 30 00:02:03,110 --> 00:02:04,470 Let's see that in action. 31 00:02:04,490 --> 00:02:07,130 Let's go to Edge to console. 32 00:02:07,460 --> 00:02:09,259 Let's refresh. 33 00:02:10,300 --> 00:02:12,500 Let's re login by connecting. 34 00:02:12,520 --> 00:02:16,000 Make sure that you are using the right JDBC URL and say connect. 35 00:02:16,450 --> 00:02:19,210 Now you can see that there is a To-Do table in here. 36 00:02:19,600 --> 00:02:23,170 So what's happening in here is that Springboard auto configuration. 37 00:02:23,170 --> 00:02:30,490 Whenever it sees H2 or any in-memory database in the class path, it will directly create tables for 38 00:02:30,490 --> 00:02:31,960 all the entities. 39 00:02:32,110 --> 00:02:35,650 When you are defining your entity, you have a lot of flexibility. 40 00:02:35,770 --> 00:02:37,810 Let's say the name of the table. 41 00:02:37,810 --> 00:02:42,820 Let's say I would want to map two is not to do, but let's say I would want to map to something else. 42 00:02:43,330 --> 00:02:48,460 So I would say name is equal to to do ABC and save. 43 00:02:52,110 --> 00:02:53,730 Let's refresh this. 44 00:02:53,910 --> 00:02:54,740 Continue. 45 00:02:54,900 --> 00:02:55,650 Connect. 46 00:02:56,560 --> 00:02:59,950 You can see that the name of the table is not to do ABC. 47 00:03:00,190 --> 00:03:05,040 So we are mapping to a table called to do ABC, to do ABC. 48 00:03:05,050 --> 00:03:07,380 By default it will use the class name itself. 49 00:03:07,390 --> 00:03:08,320 I'll remove this. 50 00:03:08,590 --> 00:03:12,590 You also have flexibility in terms of customizing the column names as well. 51 00:03:12,610 --> 00:03:16,630 Instead of calling this user name, let's say I would want to give it a different name. 52 00:03:16,930 --> 00:03:21,040 I can say column and give it a name. 53 00:03:21,880 --> 00:03:23,770 The name is equal to a name. 54 00:03:24,070 --> 00:03:31,360 Right now, if you look at this, it's called user name, but if I save this and come back. 55 00:03:32,240 --> 00:03:35,180 To which to cancel, refresh it and connect it back. 56 00:03:36,150 --> 00:03:39,630 You would see that the name is enough name. 57 00:03:40,920 --> 00:03:43,590 So this field is now mapped to this. 58 00:03:44,400 --> 00:03:47,670 JP also supports mapping complex relationships. 59 00:03:47,670 --> 00:03:48,540 One, two, 112. 60 00:03:48,540 --> 00:03:51,540 Many, many to one, many too many and things like that. 61 00:03:51,570 --> 00:03:54,450 For now, let's remove the column so I'll remove this column. 62 00:03:54,450 --> 00:03:55,620 Name is equal to name. 63 00:03:56,010 --> 00:03:59,130 I would want to continue using the default values which are generated. 64 00:03:59,130 --> 00:04:03,270 Make sure that the entity name is also true and save it out. 65 00:04:04,020 --> 00:04:08,220 And when I actually refresh this, go back and say connect. 66 00:04:08,850 --> 00:04:16,680 I should see to do table in here with the usual column names id description done targeted user name. 67 00:04:16,680 --> 00:04:18,029 So these look good. 68 00:04:18,810 --> 00:04:22,770 One thing you would have observed is target date is target underscore date. 69 00:04:22,920 --> 00:04:26,670 The reason is because there is a init cap in here. 70 00:04:26,670 --> 00:04:28,140 So this is in caps. 71 00:04:28,140 --> 00:04:34,320 So what happens is in a database typically we separate words using underscore. 72 00:04:34,710 --> 00:04:36,420 We capitalized D in here. 73 00:04:36,420 --> 00:04:41,040 That's why the column name is created as target underscore date. 74 00:04:46,220 --> 00:04:49,310 Let's organize, import and save this. 75 00:04:51,310 --> 00:04:54,610 Now, I would want to populate some data to start off. 76 00:04:54,760 --> 00:04:57,790 So how can I populate some data to start off? 77 00:04:59,740 --> 00:05:02,920 I can create a file called Data dot SQL. 78 00:05:03,110 --> 00:05:04,840 So Search Main Resources. 79 00:05:04,870 --> 00:05:07,750 New SQL file. 80 00:05:09,140 --> 00:05:11,330 Data dot SQL. 81 00:05:12,320 --> 00:05:18,470 In the data dot SQL, I can create queries and these queries will be executed at startup. 82 00:05:19,530 --> 00:05:22,620 So I'll say insert into tattoos. 83 00:05:26,230 --> 00:05:29,890 Actually insert into To-Do values. 84 00:05:30,190 --> 00:05:32,140 And you can specify the values in here. 85 00:05:35,690 --> 00:05:37,790 The default generated values start with one. 86 00:05:37,790 --> 00:05:40,190 So I'll use 10,001 as the ID. 87 00:05:44,120 --> 00:05:45,830 The second one is description. 88 00:05:46,130 --> 00:05:50,150 I'll say learn or you can say get. 89 00:05:51,490 --> 00:05:53,830 A certified. 90 00:05:56,620 --> 00:05:57,340 And. 91 00:06:02,940 --> 00:06:04,140 The next one is done. 92 00:06:04,140 --> 00:06:04,860 Which is. 93 00:06:08,230 --> 00:06:09,130 False. 94 00:06:09,160 --> 00:06:11,080 The order of these does not look good. 95 00:06:11,080 --> 00:06:17,770 So what I do is I would define my own columns in here, so I would want to insert in the right order. 96 00:06:17,770 --> 00:06:20,920 So I would want to define my own thing in here. 97 00:06:21,040 --> 00:06:27,850 So I would say ID first ID, then description, then I would want to insert. 98 00:06:28,240 --> 00:06:30,850 Actually, before description, we need to have the username. 99 00:06:33,480 --> 00:06:35,520 ID username description. 100 00:06:35,760 --> 00:06:40,870 After that would be the target date and the last one is done. 101 00:06:40,890 --> 00:06:43,020 So let's insert values in the same way. 102 00:06:43,320 --> 00:06:52,950 So let's maximize this and 1001 user username is in 28 minutes or ranga you can insert for any of those 103 00:06:52,950 --> 00:06:57,750 users and use that specific user get certified the target date. 104 00:06:58,560 --> 00:07:02,100 Let's use a hedge to function called current date. 105 00:07:02,930 --> 00:07:04,910 And is it done? 106 00:07:05,760 --> 00:07:07,140 It's false. 107 00:07:08,420 --> 00:07:09,680 And say this. 108 00:07:13,040 --> 00:07:16,670 If you go to console right enough, you'd see an error. 109 00:07:17,030 --> 00:07:26,030 It's saying table two do not found by default Data dot SQL is executed before the entities are processed. 110 00:07:26,570 --> 00:07:29,360 Tables are created when the entities are processed. 111 00:07:30,510 --> 00:07:32,790 So data dot SQL is executed before. 112 00:07:34,550 --> 00:07:37,820 The table is created and we would want to change that. 113 00:07:37,850 --> 00:07:39,050 How do we change that? 114 00:07:39,260 --> 00:07:41,750 That's where we can make a change in the application. 115 00:07:41,760 --> 00:07:42,740 What properties? 116 00:07:44,840 --> 00:07:47,480 That's something we can configure in application of properties. 117 00:07:47,480 --> 00:07:49,490 So let's open up application of properties. 118 00:07:50,280 --> 00:07:57,420 And type in spring dot JPA dot defer hyphen data source. 119 00:07:59,120 --> 00:08:06,620 Any shirt light zation, make sure that you get the spelling right it springboard JPA defer hyphen data 120 00:08:06,620 --> 00:08:12,560 source hyphen initialization is equal to true and say save. 121 00:08:13,660 --> 00:08:18,040 When I stopped and started the application again, I saw an syntax exception. 122 00:08:18,070 --> 00:08:20,740 It says column in 28 minutes not found. 123 00:08:21,250 --> 00:08:26,980 The reason why it's throwing error is because in data or SQL you should use single quotes. 124 00:08:27,340 --> 00:08:30,340 So let me replace all this with single quotes. 125 00:08:30,640 --> 00:08:33,309 So instead of double quotes, let's use single quotes. 126 00:08:40,280 --> 00:08:41,240 And take this. 127 00:08:45,410 --> 00:08:46,920 Let's see it in action. 128 00:08:48,020 --> 00:08:49,610 Let's start it again. 129 00:08:50,390 --> 00:08:51,230 Enough. 130 00:08:51,410 --> 00:08:52,940 Everything looks hunky dory. 131 00:08:52,970 --> 00:08:54,560 The application has started up fine. 132 00:08:55,730 --> 00:09:02,240 Let's go to page two console refresh and connect again to the table. 133 00:09:02,840 --> 00:09:03,920 Do you have the data? 134 00:09:04,700 --> 00:09:06,890 Yep, We have the data in here. 135 00:09:08,250 --> 00:09:11,850 Let's add a few more tattoos to data skull. 136 00:09:14,880 --> 00:09:16,050 Control a. 137 00:09:17,490 --> 00:09:20,700 So let's add a few more ID should be increased. 138 00:09:20,700 --> 00:09:22,110 You cannot have duplicate IDs. 139 00:09:22,110 --> 00:09:22,800 So 1000. 140 00:09:22,800 --> 00:09:24,090 Three 1004. 141 00:09:26,130 --> 00:09:30,810 I led all the tutus for in 28 minutes itself will be make use of intimidating its ID. 142 00:09:30,840 --> 00:09:33,330 If you want, you can make use of the wrong idea as well. 143 00:09:33,570 --> 00:09:41,400 So let's say get your certified GCP certified and let's say learn full stack or DevOps, whatever you 144 00:09:41,460 --> 00:09:43,560 want to do or learn to dance. 145 00:09:43,770 --> 00:09:45,210 All right, so what do you want to do? 146 00:09:45,240 --> 00:09:50,730 You can put them in here, make sure that the IDs are unique and save them down. 147 00:09:52,510 --> 00:09:59,320 And go back and refresh connect and to do run. 148 00:10:00,960 --> 00:10:06,400 One thing you need to remember is that even H2 is an in-memory database when you restart the application. 149 00:10:06,420 --> 00:10:08,700 All the data in H2 will be lost. 150 00:10:09,330 --> 00:10:11,610 In this step, we got the H2 database ready. 151 00:10:11,610 --> 00:10:17,940 We have the table ready, we have the data ready, and now we would want to display these to DOS connecting 152 00:10:17,940 --> 00:10:19,350 to the H2 database. 153 00:10:19,350 --> 00:10:25,890 We want to use JPA, connect to the database and show the to dos in here and we would want to use JPA 154 00:10:25,890 --> 00:10:30,960 to perform all the operations as well, delete, update, add and a wide variety of them. 155 00:10:31,080 --> 00:10:34,050 Let's get started with that starting the next step.