What is a Database

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Introduction to Data storage

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Learn Database Design with MySQL

A Complete Course to Master Database Design using MySQL

06:14:45 of on-demand video • Updated December 2018

  • To Learn Database design Process
  • To Learn Database Normalization
  • To Learn Database development using MySQL
  • To Master SQL
  • To Learn to use PHP with MySQL
English [Auto] Welcome to Chapter 1 Section 1 in this section we're going to talk about what a database actually is. And this may seem like an obvious answer especially if you have experience with my ask well or any other kind of database. But the reason that I want to start with this is because the term data base it can actually be very vague and it can mean different things to different people. All right so the bottom line the simple Dumbed-Down definition of a database is an ordered collection of data. OK. So that doesn't have to be Mya's. Well it doesn't even have to be a relational database with tables. You could actually have a notepad file with data or in that in that would actually be a flat database file. So it doesn't have to look like like my ask. Well usually when people say the word database they tend to they tend to mean one or more of these three things and these things are the data which is the actual data itself. Numbers strings dates whatever the database management system also called a DBMSs and that is what my as well as postgresql. Well Maria D-B there's a whole bunch of them that can also be referred to as the database and then sometimes people might mean the database application which is the we could say Pietsch PMI admin or my school workbench are just an interface that you use to interact with the data in that database. OK. So I don't think in my personal opinion I don't think that any of these are right or wrong. They could all in fact be called the database. In my opinion. All right. So what I want to talk about is database management systems which are also called DBMSs and that's that's what my as well is there's a whole bunch of them a devious DBMS's software that's designed to model data and provide interaction with a user. All right. So we can interact with a data base management system usually through a command line as well as Gooley tools. All right so. So we could actually use something like Pietsch my admin which we'll learn about later where we can create databases and tables and all that. All right. So data is normally stored in one or more files. These are just some quick facts about DBMS's data is usually stored in tables. Right so tables contain rows and columns and these this can look much like an Excel spreadsheet or another spreadsheet program where you have headings which would be the columns and then you have rows of data. All right. And that's looked at as a table the data can be cross-referenced among tables. All right. And this is true if it's a relational database and we're going to be talking about relational databases more in this section. So I don't want to get too deep into that but basically you can relate to one or more tables together. In my ask you owl is probably the most popular relational database that's available. Here are some other popular database management systems. All right. We have my ask you all obviously postgresql you well I've used it as is very similar to my as well in my opinion. Su all light is is a little different. You don't actually have a system it's actually pretty much just a bunch of files and it's it's really lives obviously. It's why it's called as light. Microsoft Eskew all server which is pretty much Microsoft's version of one of these of my Escudo Oracle which is a big name in relational databases. And over here we have systems that I personally have not use. We have SAP Fox pro dbase in Maria DVH and I can't tell you too much about these because I would never use them but these are just some of the popular management systems that are available. All right. So I just put together an extremely simple table that you would see inside of a relational database. And like I said we will be going into this more will create more more located and in-depth tables but this is a simple table for let's say a customer a customer management system I'd say you might have a database called my store. All right in that database you have a bunch of tables and you have a users table. All right so that's what this is. This is the users table inside of the my store database. Now inside of the users table you have columns are sometimes called fields. And in this example these fields are ID first name last name and email. And when you create your tables in your columns you should generally use either this kind of format with lowercase with an underscore separating words or use camel case which would be starting with a lower case and then the second word would have a capital in and third word would have a capital and so on. So much like javascript syntax. And then inside of those columns you have rows or sometimes called records or just data that the actual data. All right so in this table we have three users. So we have three rows with which have obviously have an ID first name. Last thing in e-mail. All right so that's a very dumbed down example of what a table is. All right. So interacting with the database we can do this with what's called the client. All right. When you install my ask you well it's actually a server it's a database server and you can use clients to connect to that database whether it's locally or remote and you can do many different things. This is just an example of some common actions that you can run against a database. You could define data or the actual database in data or inside it you can create data. You can select certain data run queries which does all of this really you can run select queries insert update delete. All right so we can do those things as well and we can do this to single fields. We can do this to a clump of fields we could do this to the table to a column name all kinds of things so we can basically do whatever we want with that data. All right. And the way that we do that in my school is through as well which stands for sorry structured query language in what it is it's a special purpose language that allows developers to interact with the data in a database. All right so all those things that we just went over we'll do that through this structured query language. It's based on relational algebra and tuple relational calculus which I'm not really familiar with. I'm obviously familiar with as well but I've never dealt with this relational calculus so I can tell you too much more about that data definition. It's a definition in data manipulation language. And we can perform a lot of different operations. But the most popular being create read update and delete. All right. And that's for sure called crud. And let's say you have a blog and you have a post table. Now you'll be able to create posts all right to insert into your blog read obviously your blog or web site will display the data in the blog to read. You can update a post and you can also delete a post. All right so every resource we create or every table we create in the database we can run these operations on our common database models. So first we have relational databases which is the most popular type of database. Obviously my school is a relational database. We have object oriented databases where everything is represented as an object object relational databases distributed databases. We have no you all databases like Mongo D-B. These are much different in my school and relational databases. Basically you don't have to define a. It's very it's very lightweight not strict but there's certain things that you don't want to use this type of database for. For instance if you have an application that performs a lot of different queries and calculations and you want to use something like my task Well I haven't use this these knows all too much. I do have some experience with Mongo DVH but that's about it. I haven't used any other ones. Multimedia databases to hold images and videos and all that flat database which is basically just a file right. So you could have just files with data in them network database and or higher hierarchial databases. And I haven't used some of these so I can't really elaborate on them but basically we'll be focusing on relational databases. All right so that's it for just a basic summary of what a database actually is. So in the next video we'll talk about my ask you all in general and what it does what it can offer us and what it can be used for.