WEBVTT 00:00.090 --> 00:06.380 So the next couple of videos are all about tables which are the most important part of sequel. 00:06.390 --> 00:12.390 They are the true heart of using sequel and in this first video we'll start off by setting the stage 00:12.390 --> 00:19.080 or setting the table if you will let me get away with that for how they work what they are and then 00:19.080 --> 00:24.360 we'll dive into data types next and then will actually create tables and see the code that you use to 00:24.360 --> 00:25.330 create them. 00:25.350 --> 00:27.470 So let's get started. 00:27.600 --> 00:32.400 The first thing you should know is that a database is just a bunch of tables. 00:32.430 --> 00:36.450 So we've already created a couple of empty databases and deleted them as well. 00:36.750 --> 00:39.530 But what goes in them are just a bunch of tables. 00:39.750 --> 00:43.400 That's where the data is stored as a short aside. 00:43.470 --> 00:50.250 This is in a relational database So everything we're talking about uses sequel things like my Escudo 00:50.460 --> 00:56.760 postscripts sequel like those are relational databases and they use tables they use tabular data but 00:56.790 --> 00:59.120 not every single database in the world does. 00:59.190 --> 01:05.040 And we'll see some examples of those later on this course is not about those types of databases but 01:05.130 --> 01:08.970 it helps to kind of bring them in to show you some contrast to what you're learning. 01:08.970 --> 01:10.490 So we'll see that later on. 01:10.680 --> 01:12.440 Just a short caveat there. 01:13.650 --> 01:14.930 So tables hold the data. 01:14.940 --> 01:19.080 That's my definition if you want the boring Wikipedia definition. 01:19.110 --> 01:20.410 It looks like this. 01:20.520 --> 01:26.310 Tables are a collection of related data held in a structured format within a database. 01:26.310 --> 01:28.110 Hopefully you're still awake after that. 01:28.530 --> 01:32.680 But let's take a quick example using CAS. 01:33.090 --> 01:36.790 So we're going to model some cat data using a table. 01:37.060 --> 01:37.660 OK. 01:37.890 --> 01:40.760 So let's take a quick look at the cats table. 01:40.780 --> 01:42.430 Drum roll please. 01:42.550 --> 01:44.070 That or die. 01:44.970 --> 01:46.730 I know it's pretty hilarious. 01:47.160 --> 01:49.030 You're probably falling out of your chair. 01:49.620 --> 01:49.950 All right. 01:49.950 --> 01:55.200 So the real cats table at least in this context doesn't have an apostrophe. 01:55.380 --> 01:56.680 Look something like this. 01:56.700 --> 02:02.530 And of course there's a million different ways we could break down the data for cat for modeling cats. 02:02.670 --> 02:06.730 In my case I just went with a name breed and age. 02:07.020 --> 02:16.060 So we could do plenty of other things like location gender is spayed is neutered that sort of thing. 02:16.200 --> 02:18.630 But just doing name breed and age. 02:19.710 --> 02:22.530 So I've put a couple of cats in here. 02:22.650 --> 02:23.540 We've got flu. 02:23.620 --> 02:25.560 Who's this Scottish Fold who's one year old. 02:25.710 --> 02:26.670 That's my cat. 02:26.890 --> 02:30.110 I've got rocket who is a Persian who's three years old. 02:30.240 --> 02:34.200 Totally made up Monte who is a tabby who is 10 years old. 02:34.260 --> 02:36.380 That is my childhood cat. 02:36.450 --> 02:40.050 He's still kicking and biting people. 02:40.080 --> 02:42.720 We've got Sam who is a munchkin. 02:42.720 --> 02:46.470 If you don't know what that breed is look them up they're pretty hilarious. 02:46.470 --> 02:51.940 Although Pender's said they have really stubby legs who is five years old also made that cat. 02:52.200 --> 02:59.280 So some terminology when we're talking about tables and you hear the term columns it's referring to 02:59.280 --> 03:01.230 the headers on that table. 03:01.260 --> 03:06.380 So what are the different components of data the different pieces that have to be there. 03:06.420 --> 03:09.840 In our case we have name breed and age. 03:09.840 --> 03:14.870 So those are the columns and then the rows are the actual data in the table. 03:14.880 --> 03:16.440 So here a row. 03:16.440 --> 03:22.290 Blue Cat is one row rocket is another row Monte is another row Sam. 03:22.350 --> 03:23.430 It's another row. 03:23.430 --> 03:28.480 I really wish those lined up correctly but I just drove myself nuts trying to get it to work. 03:28.560 --> 03:29.940 Please forgive me. 03:29.940 --> 03:34.480 Anyways so databases are made up of lots and lots of these tables. 03:34.500 --> 03:36.380 It's usually not just one. 03:36.630 --> 03:42.640 And if you have a really really simple app and you're just storing one thing then it will just be one 03:42.870 --> 03:47.430 but usually apps are pretty complicated and data is complicated. 03:47.550 --> 03:49.180 All that we modeled there was cat. 03:49.200 --> 03:55.890 But imagine if this was actually an app let's say it was a pet sitting app and cats were one thing that 03:55.890 --> 03:56.890 we had to keep track of. 03:57.000 --> 04:03.720 But we also have to keep track of owners and the pet sitters and addresses and dates and appointments 04:03.750 --> 04:06.630 and payments and those are all going to be tables. 04:06.690 --> 04:09.090 Some of them might even even be multiple tables. 04:09.210 --> 04:12.120 But for now we're not going to really worry too much about that. 04:12.180 --> 04:18.550 But just to show you sometimes it does get crazy you can click this link or I'll click it follow my 04:18.550 --> 04:25.960 own instructions to see the breakdown of some of the tables that Facebook's database or a social network 04:26.470 --> 04:28.570 might use in their database. 04:28.570 --> 04:30.670 So this is not actual. 04:30.780 --> 04:32.310 It's not 100 percent accurate. 04:32.320 --> 04:37.750 There are things that are missing or incomplete but this just shows all the different tables or at least 04:37.750 --> 04:41.170 some of the different tables involved in a pretty complex app. 04:41.170 --> 04:43.700 So as you can see there is a bunch of them here. 04:43.720 --> 04:51.620 Things like accounts and events and message notification Web site screen name address blah blah blah 04:51.640 --> 04:55.100 all these different things to take into consideration. 04:55.210 --> 04:56.640 So things can get messy. 04:56.830 --> 05:02.440 And as you progress in this course you will start working with multiple tables you'll see how they connect. 05:02.440 --> 05:05.070 But we haven't even seen how to create a single table yet. 05:05.110 --> 05:09.170 So we're going to focus just on individual tables and then we'll move on from there.