RDBMS Concepts

Quick reference

• 00:04 In this video I want to talk about RDBMS concepts, and
• 00:08 that's Relational Database Management System Concepts.
• 00:12 Basically, what is a database,
• 00:14 what's it made up of, what are the parts involved in it on a very basic level.
• 00:18 So we're going to look at core concepts like the structure of a database,
• 00:21 such as tables, columns, rows, and things like that.
• 00:24 So, really drilling down to the bare bones of what is a database, and
• 00:28 what you can expect to find in them.
• 00:29 And it doesn't really matter what type of database you're going to use: SQL,
• 00:34 MySQL, Postgres,
• 00:36 any type of major SQL based database is gonna have this same structure.
• 00:40 So what I've done here is I've opened up just Microsoft Excel.
• 00:43 And Excel is just a spreadsheet program, but it's very popular.
• 00:47 Likely you've seen or used it before in the past.
• 00:49 And when you really think about it, Excel and
• 00:52 really any spreadsheet is sort of like mini database.
• 00:55 It has the same structure, the same components, and the same layout as
• 00:59 a database, so it's a good tool to sort of use to show these concepts.
• 01:03 So I've just gotta a basic Excel spreadsheet open and
• 01:06 you see we have all these squares, right?
• 01:09 Well, this thing is made up of columns.
• 01:11 That's this.
• 01:13 And rows, which go across like this.
• 01:16 And that's the basic layout.
• 01:18 So think of this spreadsheet, think of Excel as a database.
• 01:22 The whole big thing is a database.
• 01:25 Now down here, we have these different tabs.
• 01:27 So we have Sheet 1, Sheet 2, and Sheet 3.
• 01:29 So if we're on Sheet 1, if I type some stuff.
• 01:32 I click on the Sheet 2.
• 01:33 It's empty, I can type more stuff.
• 01:36 Sheet 3 doesn't have anything at all.
• 01:38 So think of each of these sheets as a table.
• 01:41 Everything on this screen is a table, right?
• 01:44 And your database, Excel, the main program can have lots of different tables,
• 01:50 lots of different worksheet, okay?
• 01:52 So that's the first concept, databases are made up of tables.
• 01:56 The tables, the individual tables are like the units that you need to be aware of,
• 02:01 it's the main unit of a database.
• 02:03 So you have the database Excel.
• 02:04 For our purposes,it doesn't do much but hold the tables, right?
• 02:08 So it's in the tables themselves where you're gonna be doing most of your work,
• 02:12 where you keep all your data.
• 02:14 And you can have lots of different tables.
• 02:15 You can have a table for current customers, past customers,
• 02:18 potential customers.
• 02:20 Whatever you wanna do, however you wanna label these different tables,
• 02:22 you can do that.
• 02:24 Let's rename this sheet.
• 02:26 Just to make things clear, current customers, right?
• 02:30 So our table is current customers and inside that we have columns.
• 02:34 So let's say, first name, last name,
• 02:39 email address, phone number, mailing address.
• 02:45 And we can click on each of these to resize these a bit,
• 02:48 just to make things clear.
• 02:52 Each of these columns is a major thing we wanna record, first name, last name,
• 02:56 email address, right?
• 02:57 So in sort of database lingo, we call these columns, but we also call them
• 03:02 a field and we call these rows, but we also call them a record, right?
• 03:06 So each row is its own record, sort of important to understand.
• 03:10 We can have John Elder.
• 03:15 Now everything in this row goes together.
• 03:18 This is all data from one record, right?
• 03:22 One person, in this case, John Elder, me, my email address, my phone number, and
• 03:27 my mailing address.
• 03:27 So, whenever we want to look up something, we'll often look up something from
• 03:32 a certain row or we might say, give me all the rows.
• 03:35 Or we might say give me all the rows with first name John or whatever.
• 03:38 And our SQL stuff allows us to do these things.
• 03:40 But this right here,
• 03:42 what we're looking at right now is basically pretty much everything.
• 03:45 I mean this is the main concepts of databases.
• 03:47 This is what you gotta wrap your head around.
• 03:49 You have Excel here, in this case, which is the overall database.
• 03:54 Inside the database, we have different worksheets.
• 03:58 We can have as many worksheets as we want.
• 04:01 And inside each worksheet, we have columns and rows, columns or fields.
• 04:06 So each of these is a field, right?
• 04:07 An email address field, a phone number field, a mailing address field.
• 04:13 And each of these rows is a record.
• 04:15 And everything in the row goes together.
• 04:18 And one more thing to note, each of these items of data, and
• 04:21 we'll talk about this in the next video, deals with a certain type of data.
• 04:25 Like this phone number, these are numbers obviously.
• 04:28 This last name is text.
• 04:30 And each field has different characteristics.
• 04:32 And we'll talk about that in the next video.
• 04:33 But that's pretty much it.
• 04:35 So if you can understand this basic concept,
• 04:38 you're most of the way to understanding how databases work.
• 04:41 And it's really not any more complicated that this.
• 04:43 In the next video, we'll talk about each of these fields and their data type.

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