WEBVTT 00:07.460 --> 00:07.850 All right. 00:07.850 --> 00:14.720 So let's go ahead and assign phones to our students is in the foreign key constraint which we created 00:14.720 --> 00:16.280 in the previous lecture. 00:16.370 --> 00:19.130 Now let's go ahead and see at tables. 00:19.130 --> 00:26.840 So select uh oh from students. 00:26.840 --> 00:32.810 And then this you can see that uh each of these students, none of them have a phone assigned to them. 00:32.810 --> 00:36.590 So only the phone ID, it is actually nothing there. 00:36.590 --> 00:47.030 And then let's go ahead and see the phone on this guy and say select uh oh from phone and put a semicolon 00:47.030 --> 00:47.540 at the end. 00:47.540 --> 00:49.010 And let's go ahead and check it out. 00:49.070 --> 00:54.320 Now we have to know how I made and Samsung and want to assign one of these. 00:54.350 --> 00:55.250 Let's go ahead and see. 00:55.250 --> 00:58.400 I'm going to assign some song to George Steve. 00:58.400 --> 01:04.120 And if I want to do that how can I be able to do that using the foreign keys. 01:04.480 --> 01:13.090 If I want to assign a form to Steve, or I need to do is to go ahead and say update, and I'm going 01:13.090 --> 01:16.120 to update the students table. 01:16.120 --> 01:26.770 So update students and I'll go ahead and set this form, the form table, which is here. 01:26.770 --> 01:35.950 And go ahead and say set a form underscore ID uh equal to. 01:35.980 --> 01:37.570 I'll go ahead and select three. 01:37.600 --> 01:43.510 If I select three that means I want to assign the ID three which is Samsung, to Steve. 01:43.510 --> 01:44.830 And that is three. 01:44.830 --> 01:49.120 And then I'm going to assign that via this ID is equal to one. 01:49.120 --> 01:53.440 So go ahead and say assign that where id is equal to one. 01:53.440 --> 01:58.360 And put a semicolon and the id where id which is stress ID. 01:58.720 --> 02:00.190 Go ahead and delete this. 02:00.190 --> 02:06.090 We are Students underscore ID is equal to one. 02:06.390 --> 02:06.750 All right. 02:06.780 --> 02:11.370 So if you go ahead and hit enter we can see we have update. 02:11.370 --> 02:18.510 And let's go ahead and uh select oh from. 02:22.740 --> 02:23.250 Students. 02:23.250 --> 02:25.350 And put a semicolon at the end and hit enter. 02:25.350 --> 02:33.960 And right now you can see that Steve has uh some song which is ID uh, font ID three assigned to it. 02:33.990 --> 02:36.990 So you can see that we have assigned this to Judge Steve. 02:36.990 --> 02:45.330 And if I want to assign Motora to maybe to Toby or Lulu, I'll go ahead and say, okay, we're going 02:45.330 --> 02:49.380 to assign this to Lulu, and I'm going to assign it to Lulu. 02:49.380 --> 02:55.320 And then what I need to do is that, uh, the ID of row is two added ID the font ID is one. 02:55.320 --> 02:59.220 So I'll go ahead and say update. 03:01.340 --> 03:04.880 The streets. 03:04.910 --> 03:05.900 The table. 03:05.930 --> 03:14.750 Then go ahead and set the phone underscore ID equal to that is your phone underscore ID is one for Motorola. 03:14.750 --> 03:20.960 And uh go ahead and see where the stress ID. 03:24.020 --> 03:30.530 Where the students underscore ID is equal to that is zero is equal to three. 03:30.530 --> 03:36.980 So when I say stress underscore ID is equal to three, I'll put a semicolon at the end and hit enter. 03:36.980 --> 03:38.630 And we have this updated. 03:38.660 --> 03:45.830 Now if I go ahead and uh select oh from. 03:47.900 --> 03:48.410 Stress. 03:48.410 --> 03:50.840 And put a semicolon at the end and hit enter. 03:50.840 --> 03:59.300 You can see that uh, George has some song which is uh, the ID three for Samsung assigned to it while 03:59.330 --> 04:08.960 rural has, uh, this, which is, a muttaburra and that is the ID one assigned to it. 04:08.960 --> 04:11.690 So we have to stress assign phones. 04:11.720 --> 04:22.790 Now let me go ahead and see that maybe we want to assign this some song and some song is ID three. 04:22.820 --> 04:24.470 I'll go ahead and drag this down a little bit. 04:24.500 --> 04:25.820 Samsung is ID three. 04:25.820 --> 04:32.240 And once I assign that to maybe topi and topi which has not anything assigned to it. 04:32.270 --> 04:34.790 If we go ahead and do that, let's see what is going to happen. 04:34.820 --> 04:35.840 Go ahead and say. 04:38.210 --> 04:39.170 Updates. 04:41.540 --> 04:42.320 Strains. 04:43.250 --> 04:50.810 Uh, table and dashboard and uh, sets phone underscore ID equal to. 04:50.840 --> 05:03.040 And that is three for the Samsung where the students underscore ID is equal quote tool. 05:03.160 --> 05:06.040 Let me say maybe it's for 2 or 3 for two. 05:06.310 --> 05:09.490 That is the flow. 05:09.520 --> 05:11.920 And put the semicolon at the end and hit enter. 05:11.920 --> 05:16.990 And now you can see we have a duplicate key value versus the unique constraint. 05:16.990 --> 05:20.470 Because we make that issue so that we have a phone assigned to them. 05:20.470 --> 05:25.330 So if we want to do that we have to go ahead and insert a new phone right in here. 05:25.360 --> 05:30.010 Or we go ahead and insert email because no two students will have the same phone. 05:30.040 --> 05:30.700 All right. 05:30.730 --> 05:33.940 That is it because the IDs are separate. 05:33.940 --> 05:38.650 So you're not going to send ID, which I've assigned to a student to another student. 05:38.680 --> 05:45.610 But if I go ahead and copy everything right in here and go ahead and paste it here, and I change the 05:45.640 --> 05:48.400 ID of the phone and we have one of them remaining. 05:48.400 --> 05:54.250 And that is two for I met and I changed it up to two and put a semicolon and hit enter. 05:54.280 --> 05:59.200 And uh let's see okay. 05:59.200 --> 06:03.360 So we have this where the stress ID is equal to two. 06:03.390 --> 06:05.940 So we're talking about the font we have assigned the font. 06:05.970 --> 06:13.080 When I press this and I'll go right in here and change the font ID to white and change this font ID 06:13.410 --> 06:14.820 to two. 06:15.720 --> 06:16.320 All right. 06:16.320 --> 06:21.450 And now let's go ahead and uh hit enter and see what happens. 06:21.480 --> 06:23.130 Now I have updated that. 06:23.130 --> 06:33.270 So go back and uh select uh oh from students and put a semicolon at the end and hit enter. 06:33.270 --> 06:36.300 And now you can see that Toby has. 06:36.300 --> 06:38.850 Now I made a sign to him. 06:39.060 --> 06:43.980 So now two strings are going to have the same phone, uh, with font ID assigned to them. 06:43.980 --> 06:46.530 And that is the part of foreign keys. 06:46.530 --> 06:52.710 So we are referencing the two tables, and you can see that you cannot assign a foreign which you are 06:52.710 --> 06:56.010 assigned to a students already to another student. 06:56.040 --> 06:56.700 All right. 06:56.700 --> 07:05.570 And uh, let's go ahead and say maybe backward slash DC to see everything and to have these two tables 07:05.570 --> 07:06.290 right in here. 07:06.290 --> 07:09.530 And these two tables are actually communicating. 07:10.310 --> 07:15.650 So if you go ahead and let me go ahead and say, I want to view this table, because that is where the 07:15.650 --> 07:22.700 foreign key is actually is going in and say, uh, backward slash D and then go ahead and view students 07:22.700 --> 07:23.720 and hit enter. 07:23.750 --> 07:26.210 Now you can see we have foreign key constraint. 07:26.210 --> 07:31.640 And that is trans underscore foreign aid underscore f uh t. 07:31.700 --> 07:34.550 And that is the foreign L. 07:34.580 --> 07:37.010 The phone ID cannot be assigned to two persons. 07:37.010 --> 07:40.040 And you can see that is the foreign key references. 07:40.040 --> 07:44.660 So every students need to have a unique phone ID assigned to them. 07:44.660 --> 07:46.190 So I hope that is cool. 07:46.280 --> 07:47.360 Go ahead and put this down. 07:47.390 --> 07:48.080 Foreign rotate. 07:48.080 --> 07:51.380 And if you have any question go ahead and use the question and answer section. 07:51.380 --> 07:53.780 And I'm going to get back to you as soon as possible. 07:53.810 --> 07:54.710 Thank you so much. 07:54.710 --> 07:57.680 And I'm going to see you in the next video lecture.