1 00:00:00,697 --> 00:00:02,560 - [Narrator] Hi, and welcome back to the course. 2 00:00:02,560 --> 00:00:05,985 In this video we're going to look at deleting items. 3 00:00:05,985 --> 00:00:10,289 Once again, it's going to be the same as the create item. 4 00:00:10,289 --> 00:00:12,777 Only instead of inserting into a database, 5 00:00:12,777 --> 00:00:16,915 we are going to be deleting from a database. 6 00:00:16,915 --> 00:00:18,248 Let's go for it. 7 00:00:19,147 --> 00:00:23,079 Our current delete method takes in the global variable items 8 00:00:23,079 --> 00:00:26,377 which, as you remember, was our list of items, 9 00:00:26,377 --> 00:00:28,964 and then essentially filtered a name out. 10 00:00:28,964 --> 00:00:31,161 Filter the, an element out where 11 00:00:31,161 --> 00:00:34,109 the name didn't match the names. 12 00:00:34,109 --> 00:00:36,537 Or rather, filtered in all of the elements 13 00:00:36,537 --> 00:00:38,008 where the name didn't match the name. 14 00:00:38,008 --> 00:00:40,530 So essentially, ended up with an item less. 15 00:00:40,530 --> 00:00:42,219 We're no longer gonna do that. 16 00:00:42,219 --> 00:00:44,802 Instead what we're gonna do is, 17 00:00:46,090 --> 00:00:47,759 you guessed it, 18 00:00:47,759 --> 00:00:49,121 we're gonna copy this in this case 19 00:00:49,121 --> 00:00:51,533 because I don't wanna bore you too much. 20 00:00:51,533 --> 00:00:53,412 We're gonna initialise a connection, 21 00:00:53,412 --> 00:00:55,838 create a cursor, and then create a query. 22 00:00:55,838 --> 00:00:59,701 The query is going to delete from a table. 23 00:00:59,701 --> 00:01:03,150 So, you guessed it, delete from. 24 00:01:03,150 --> 00:01:05,015 We're gonna delete from items, 25 00:01:05,015 --> 00:01:07,500 but we're not gonna delete specific values, 26 00:01:07,500 --> 00:01:09,491 that's only used with columns, 27 00:01:09,491 --> 00:01:13,170 we're gonna delete from items where the name 28 00:01:13,170 --> 00:01:15,587 is equal to a specific value. 29 00:01:16,855 --> 00:01:18,072 Okay? 30 00:01:18,072 --> 00:01:19,572 And the name equal 31 00:01:22,038 --> 00:01:22,871 the name 32 00:01:24,291 --> 00:01:26,458 that is passed in the URL. 33 00:01:27,817 --> 00:01:31,907 Now this part here of the where clause is really important, 34 00:01:31,907 --> 00:01:33,432 really, really important. 35 00:01:33,432 --> 00:01:35,968 Because if you skip it, or you forget to type it in, 36 00:01:35,968 --> 00:01:38,307 that deletes everything from the table. 37 00:01:38,307 --> 00:01:42,041 And you most likely don't want to do that, okay? 38 00:01:42,041 --> 00:01:46,120 So make sure to have a where clause that is very specific. 39 00:01:46,120 --> 00:01:50,257 The name, in our case, is unique to each row. 40 00:01:50,257 --> 00:01:53,217 So if we delete where the name is equal to something, 41 00:01:53,217 --> 00:01:57,286 we know we're only ever gonna delete one row. 42 00:01:57,286 --> 00:01:59,712 You could do other things. 43 00:01:59,712 --> 00:02:02,211 For example imagine you have a table of students. 44 00:02:02,211 --> 00:02:06,378 You could delete where the age is greater than 15, say. 45 00:02:07,729 --> 00:02:10,464 And then that could delete many, many students. 46 00:02:10,464 --> 00:02:13,082 So that's usually not the way you want to delete things. 47 00:02:13,082 --> 00:02:15,947 It may be, but usually it isn't. 48 00:02:15,947 --> 00:02:18,850 Normally you want to delete a specific element, 49 00:02:18,850 --> 00:02:21,930 and that's how you make sure that you're doing that. 50 00:02:21,930 --> 00:02:26,097 Make sure that the where is using that unique column. 51 00:02:28,527 --> 00:02:32,110 Okay, that's it, for this video really. 52 00:02:32,110 --> 00:02:35,713 Let's save that, and go over to Postman. 53 00:02:35,713 --> 00:02:39,751 And once again we are going to create an item, 54 00:02:39,751 --> 00:02:42,334 which I think I have done here. 55 00:02:43,186 --> 00:02:44,852 We're going to create the item. 56 00:02:44,852 --> 00:02:46,718 Oh, it already exists, because we've not changed 57 00:02:46,718 --> 00:02:48,660 the date or gone DB, so now what we can do 58 00:02:48,660 --> 00:02:52,827 is go over to the delete endpoint, and put test in it. 59 00:02:53,827 --> 00:02:56,457 And now we get back item deleted. 60 00:02:56,457 --> 00:02:59,286 Now, there's no way for us to check, 61 00:02:59,286 --> 00:03:00,619 unless we go and 62 00:03:02,382 --> 00:03:04,299 get that specific item. 63 00:03:05,665 --> 00:03:06,498 What do you think's gonna happen 64 00:03:06,498 --> 00:03:10,132 when I do this, when I press send? 65 00:03:10,132 --> 00:03:11,632 Take a wild guess. 66 00:03:14,674 --> 00:03:17,447 Ah-ha! I'm sure you got that, because I just opened 67 00:03:17,447 --> 00:03:20,199 this get endpoint new, so it doesn't have 68 00:03:20,199 --> 00:03:22,677 the most recent header, so what we have to do 69 00:03:22,677 --> 00:03:26,844 is go to authenticate again and make sure to copy that. 70 00:03:27,729 --> 00:03:29,416 In a later video I'm gonna teach you a trick, 71 00:03:29,416 --> 00:03:31,597 so you don't have to do this every time. 72 00:03:31,597 --> 00:03:33,578 But, for now let's leave it as this. 73 00:03:33,578 --> 00:03:35,976 Let's go back to the get a specific item, 74 00:03:35,976 --> 00:03:40,526 and make sure in the header to put your JWT space 75 00:03:40,526 --> 00:03:43,819 and your access token, and now we can see 76 00:03:43,819 --> 00:03:48,198 that item is not found because we have deleted it. 77 00:03:48,198 --> 00:03:50,930 Okay, so that's everything for this video then. 78 00:03:50,930 --> 00:03:53,673 How to delete item is just the same as always, 79 00:03:53,673 --> 00:03:55,989 but deleting from the table 80 00:03:55,989 --> 00:03:58,777 instead of inserting or selecting. 81 00:03:58,777 --> 00:03:59,726 Hope you enjoyed it, and 82 00:03:59,726 --> 00:04:01,507 I'll see you in the very next video.