WEBVTT 00:00.270 --> 00:00.690 All right. 00:00.690 --> 00:07.260 So we're going to start off by taking a bit of a step back and talking about two very high level general 00:07.260 --> 00:12.960 questions that are pretty central to everything this course is about and they are. 00:12.960 --> 00:18.780 First off what is database seems like a pretty straightforward question but there is a little bit of 00:18.780 --> 00:21.060 terminology you need to discuss. 00:21.870 --> 00:24.670 And then secondly why do they matter. 00:24.810 --> 00:30.690 So let's start off with the first one what is a database what actually makes something database and 00:30.750 --> 00:33.830 there are a couple of definitions that we could go with here. 00:33.840 --> 00:38.410 I kind of synthesized some of them into my own definition that has two parts. 00:38.610 --> 00:45.200 And the first part is that it's a collection of data which seems pretty straightforward. 00:45.210 --> 00:51.090 There are all sorts of collections of data around us in the real world things like when you go to your 00:51.090 --> 00:57.810 doctor's office and there's a filing cabinet full of medical records or even just that a to do list 00:57.810 --> 01:04.260 or a list of things to buy at the grocery store qualifies as a collection of data or going back a little 01:04.260 --> 01:05.000 bit in time. 01:05.040 --> 01:12.360 If you remember what Rolodexes word a Rolodex full of different people's contact information that qualifies 01:12.360 --> 01:13.120 as a database. 01:13.140 --> 01:14.450 Under this definition. 01:14.610 --> 01:18.560 Speaking of archaic technology like a Rolodex. 01:18.630 --> 01:22.620 Another example of a database is a phone book. 01:22.770 --> 01:28.920 So I say this mainly jokingly but I actually have some siblings who don't know what phone book is or 01:28.920 --> 01:30.990 they've never seen one or used one before. 01:30.990 --> 01:36.670 It's a gigantic book basically that you look up people's phone numbers based off of their name. 01:37.050 --> 01:40.920 So it's usually organized by last name alphabetically for people. 01:40.950 --> 01:45.090 So you would look through the book until you find someone's last name and then you would try and match 01:45.090 --> 01:47.300 the first name and then you find the phone number. 01:47.340 --> 01:49.700 So let's take a quick example here. 01:49.710 --> 01:51.610 This is a fictional phonebook. 01:51.750 --> 01:56.800 Think of it as just a little section of a phone book that has tens of thousands of entries. 01:57.030 --> 02:01.020 And these are fictional characters alphabetically organized by their last name. 02:01.020 --> 02:06.150 So Archie Andrews comes in for Betty Cooper who comes before Ned Flanders and so on. 02:06.510 --> 02:08.600 And then we have corresponding phone numbers. 02:09.490 --> 02:12.780 So imagine you have a gigantic phonebook with this information in it. 02:12.910 --> 02:19.390 And I asked you to do something like find Ned Flanders phone number Well it's actually pretty straightforward 02:19.750 --> 02:23.660 as long as you're comfortable using the alphabet in alphabetical order. 02:23.830 --> 02:29.380 You look through the book until you find f f l and so on until you find Ned Flanders and then you find 02:29.380 --> 02:30.570 his phone number. 02:30.600 --> 02:32.550 It's what the phone book is made for. 02:32.920 --> 02:38.920 However it gets a little trickier or a lot trickier it really if I ask you to do something like find 02:38.950 --> 02:41.330 everyone in the phone book who has the first name. 02:41.360 --> 02:45.360 Ned there isn't an easy way to do this. 02:45.560 --> 02:50.820 You basically would have to go through every entry in the book and check for how many thousands there 02:50.820 --> 02:53.180 are is this person's name. 02:54.860 --> 02:58.670 So I have a couple other questions that are similarly difficult. 02:58.760 --> 03:04.240 So the point here is just if you were to find all phone numbers with a particular area code or to find 03:04.240 --> 03:09.390 all people who have a three letter first name it's not easy and it would take a lot of time. 03:09.670 --> 03:11.560 Like a ton of time. 03:11.780 --> 03:17.410 So that brings me to the next component of the definition of what makes something a database. 03:17.690 --> 03:21.380 In my opinion which is not just a collection of data. 03:21.500 --> 03:26.310 It also contains a method for accessing and manipulating that data. 03:26.330 --> 03:32.720 So going back to this phone book we would want a way some sort of program or code that would allow us 03:32.720 --> 03:38.060 to do things like find everybody with the first name net or find all people who have a three letter 03:38.060 --> 03:45.980 first name or even do things like add a new person into the phone book or change area codes or change 03:45.980 --> 03:51.040 phone numbers or get crazy and just delete people from our phone book or delete everybody if we wanted 03:51.050 --> 03:57.260 to we would have some sort of program or code as part of our database that would help with that that 03:57.260 --> 04:00.220 would allow us to interface with the data. 04:00.770 --> 04:05.310 So I did say we were going to dive a little bit into the jargon and terminology. 04:05.450 --> 04:09.710 I usually try to stay away from that early on while I try and stay away from that in general but especially 04:09.710 --> 04:11.140 early on in the course. 04:11.530 --> 04:17.480 Basically if you've read about databases if you've used one before if you've read a blog post about 04:17.480 --> 04:23.600 them you may have come across the term database management system or relational database management 04:23.600 --> 04:29.170 system or DMX or RB DNS all these different acronyms. 04:29.450 --> 04:36.110 Basically this right here what I have on the screen database versus database management system refers 04:36.110 --> 04:42.260 to the fact that what I just talked about having data collection of data and then having an interface 04:42.260 --> 04:45.270 for that data are two different things. 04:45.380 --> 04:47.900 So let me show you a quick example. 04:47.900 --> 04:50.240 Imagine that you have an application. 04:50.600 --> 04:57.350 Let's say it is a dating app and then you have a database and you're storing all sorts of information 04:57.380 --> 05:03.080 all the different users all the different messages that have been sent the photos whatever else goes 05:03.080 --> 05:05.320 into your dating app but on its own. 05:05.360 --> 05:08.390 The database here is basically like our phone book. 05:08.390 --> 05:16.250 It's a gigantic collection of data which is great for storing data but it really doesn't do very much. 05:16.250 --> 05:19.940 You can almost think of it as if it was a gigantic file on your computer. 05:19.940 --> 05:28.070 So for our application to be able to do things like Update somebody's username in the database or edit 05:28.100 --> 05:34.700 their profile photo or delete a user if they want to leave our application whatever it is there's a 05:34.700 --> 05:39.140 database management system that allows us to interface with that database. 05:39.170 --> 05:43.900 So it's just the code to the program that does the talking to our database for us. 05:43.910 --> 05:48.360 So we talked to our database management system and it talks to the database. 05:48.380 --> 05:48.800 OK. 05:48.830 --> 05:52.170 So for the most part we're out of the weeds with the jargon here. 05:52.190 --> 05:58.940 The reason I brought this up though is that oftentimes when people talk about data rates you actually 05:58.940 --> 06:01.700 hear them referring to both of these things. 06:01.700 --> 06:07.190 The database management system and the database together just as a database. 06:07.580 --> 06:12.240 So what I have right here is a list of some of the more common databases you'll run into. 06:12.560 --> 06:17.110 And actually I just did it there when I was just talking about these four things. 06:17.160 --> 06:20.760 PostgreSQL my Eskew Well Oracle sequel lite. 06:20.810 --> 06:22.730 They're not technically databases. 06:22.850 --> 06:25.470 They're actually database management systems. 06:25.850 --> 06:29.160 But for the most part people just call them databases. 06:29.360 --> 06:34.700 So when we say things like my as well as one of the most commonly used databases it's actually one of 06:34.700 --> 06:37.820 the most commonly used database management systems. 06:37.910 --> 06:42.380 So it's not the end of the world if you forget about that but it is important because it will help you 06:42.380 --> 06:47.810 understand later on when we actually start talking about a sequel when we start talking about some of 06:47.810 --> 06:50.860 the code that you write to interact with the database. 06:50.900 --> 06:55.730 I think it will help you understand what you're doing and that you're giving commands to this database 06:55.730 --> 07:02.130 management system which then goes and gives commands to the actual data itself or to the database itself. 07:02.480 --> 07:08.360 OK so to wrap everything up here's a little bit of a synthesized definition. 07:09.560 --> 07:10.520 What is a database. 07:10.580 --> 07:15.930 Well it's a structured set of computerized data with an accessible interface.