1 00:00:04,700 --> 00:00:05,700 Welcome back. 2 00:00:06,500 --> 00:00:07,860 In the previous video, 3 00:00:07,860 --> 00:00:10,160 we added the code to the contracts class 4 00:00:10,460 --> 00:00:12,760 to upgrade our database to version 4. 5 00:00:13,560 --> 00:00:15,560 Version 3 contains a new view, 6 00:00:15,960 --> 00:00:18,660 and we've seen the upgrade from version 2 working. 7 00:00:18,660 --> 00:00:21,460 Of course, we don't know that it really works 8 00:00:21,460 --> 00:00:24,660 because we haven't written any code to use the view yet. 9 00:00:25,660 --> 00:00:29,660 But at least we know that the view gets created. Well, we think we know. 10 00:00:29,660 --> 00:00:31,160 There wasn't an error at least. 11 00:00:32,960 --> 00:00:35,560 To be sure we can examine the database on the phone, 12 00:00:36,060 --> 00:00:37,960 I'll do it from the terminal this time. 13 00:00:38,160 --> 00:00:41,760 But if you don't have access to your phone, you can copy the database 14 00:00:41,760 --> 00:00:43,120 back to your computer. 15 00:01:01,720 --> 00:01:06,490 With the database open, we can check the schema to make sure our view exists. 16 00:01:10,990 --> 00:01:13,590 That's fine, there's our view created. 17 00:01:14,250 --> 00:01:18,850 Some versions of SQLite add a comment to the end of the view when displaying the schema. 18 00:01:19,650 --> 00:01:23,310 That's helpful, but you shouldn't include it in your code to create the view. 19 00:01:23,860 --> 00:01:26,860 All right. Do we still have data in the database? 20 00:01:40,060 --> 00:01:44,420 It's important to test that your upgrade does preserve the existing data. 21 00:01:44,970 --> 00:01:49,170 Users won't be impressed if your app wipes out their data after updating itself. 22 00:01:49,830 --> 00:01:54,190 Okay, to test the upgrade from version 1 to version 3, 23 00:01:54,590 --> 00:01:58,390 we need to copy our version 1 database onto the device, 24 00:01:59,390 --> 00:02:00,690 quit SQLite. 25 00:02:04,690 --> 00:02:08,490 Also make sure the app isn't running on the emulator. 26 00:02:12,290 --> 00:02:16,290 Replacing the database file while the app's running could cause problems. 27 00:02:16,840 --> 00:02:20,740 So if it's running use the stop button in android studio to stop it. 28 00:02:21,540 --> 00:02:24,640 We've already seen how to copy files from the device 29 00:02:24,890 --> 00:02:26,490 using the device explorer. 30 00:02:27,290 --> 00:02:29,890 We can also copy files to the device. 31 00:02:30,770 --> 00:02:34,670 I'm going to replace the database with my version 1 database 32 00:02:34,670 --> 00:02:36,670 that I copied in an earlier section. 33 00:02:37,170 --> 00:02:39,370 We could be causing a problem here though. 34 00:02:40,030 --> 00:02:42,530 If there's a journal file from version 4, 35 00:02:42,930 --> 00:02:46,130 it could make our version 1 database unusable. 36 00:02:47,130 --> 00:02:50,330 It's a good idea to clear out the existing files first 37 00:02:50,730 --> 00:02:52,530 before copying the new database. 38 00:02:53,030 --> 00:02:57,690 I'll navigate to /data/data/learnprogramming 39 00:02:57,890 --> 00:03:01,990 .academy.tasktimer in the device file explorer, 40 00:03:02,350 --> 00:03:04,650 then expand the databases directory. 41 00:03:17,450 --> 00:03:20,650 I suggest you delete all the existing files 42 00:03:20,650 --> 00:03:23,010 before copying new ones onto the device. 43 00:03:24,010 --> 00:03:26,370 Select the task timer DB file 44 00:03:26,920 --> 00:03:29,280 and any journal files that may be present, 45 00:03:29,880 --> 00:03:32,280 then press the del button to delete them. 46 00:03:35,640 --> 00:03:38,000 You can also right click and choose delete, 47 00:03:38,550 --> 00:03:41,450 but I probably don't need to tell you that at this point in the course. 48 00:03:42,350 --> 00:03:46,850 After deleting the existing files, right click databases 49 00:03:46,850 --> 00:03:48,450 and choose upload. 50 00:03:54,050 --> 00:03:57,050 I want to copy my version 1 database, 51 00:03:57,410 --> 00:03:59,810 so I'll select all the files in my 52 00:03:59,810 --> 00:04:04,210 tasktimerdb-version1 directory before clicking okay. 53 00:04:17,910 --> 00:04:20,269 Device file explorer pops up a message 54 00:04:20,630 --> 00:04:24,630 at the bottom to let you know if the file transfer was successful or not. 55 00:04:25,290 --> 00:04:29,290 All right. Run the app again, and keep an eye on the logcat. 56 00:04:42,890 --> 00:04:46,250 I'll close the device file explorer because we don't need it at the moment. 57 00:04:49,610 --> 00:04:53,270 We should see the SQL commands to create the timings table 58 00:04:53,600 --> 00:04:57,700 and its trigger followed by the command to create the two views. 59 00:05:09,060 --> 00:05:13,610 Close the app down, and run SQLite 3 on the device again. 60 00:05:16,110 --> 00:05:18,110 My terminal is still in the device shell 61 00:05:18,610 --> 00:05:20,810 but you know how to get to the right place by now. 62 00:05:26,410 --> 00:05:28,770 We can check the data in our database. 63 00:05:36,770 --> 00:05:39,770 We've got the new table and the view 64 00:05:39,770 --> 00:05:41,970 and there's still data in the tasks table. 65 00:05:42,470 --> 00:05:44,970 The timings table should be empty, 66 00:05:49,330 --> 00:05:51,830 which is fine. It's only just been created. 67 00:05:52,490 --> 00:05:55,480 We can generate some timing data from the apps menu, 68 00:05:55,480 --> 00:05:58,080 so switch back to the emulator, and do that. 69 00:06:06,680 --> 00:06:08,680 Once a logcat stops updating, 70 00:06:10,180 --> 00:06:13,480 switch back to the terminal window and check the database. 71 00:06:21,780 --> 00:06:24,780 We've now got a version 4 database on the device 72 00:06:24,780 --> 00:06:26,980 upgraded from version 1. 73 00:06:27,970 --> 00:06:32,270 It won't do this, but we should also uninstall the app and run it again. 74 00:06:32,930 --> 00:06:35,530 That will test the database creation process. 75 00:06:36,030 --> 00:06:38,830 Remember that you'll have new users of the app 76 00:06:39,190 --> 00:06:42,190 not everyone will be upgrading from an earlier version. 77 00:06:42,490 --> 00:06:45,090 It's very important to test both processes; 78 00:06:45,450 --> 00:06:48,150 the upgrade and the new database creation. 79 00:06:48,650 --> 00:06:52,150 You should also test the upgrade from version 2 to version 4. 80 00:06:52,810 --> 00:06:55,210 Whichever database version you start with, 81 00:06:55,210 --> 00:06:59,310 you should end up with exactly the same database schema after the upgrade. 82 00:07:00,110 --> 00:07:03,310 Okay. Quit SQLite and the terminal. 83 00:07:07,310 --> 00:07:11,410 In the next video, we'll create the layouts to display the data 84 00:07:11,610 --> 00:07:12,610 for a new view. 85 00:07:13,270 --> 00:07:14,270 I'll see you in that one.