Original subtitles

‫All right, so database software, we keep talking about this, we keep talking about databases being

‫the data we store and it being stored in a specific way called the model.

‫But we never really dove deep into what actually makes this happen.

‫Well, that is called the database management software.

‫And it's a piece of software that basically says, OK, I am going to manage your database, I'm going

‫to be your supervisor.

‫I know all of the rules about the way you want to store your data.

‫I know your model.

‫And when you give me an actual query, I know exactly how to get your data and give it back to you.

‫It's kind of like your mediator or your manager.

‫It's there and it knows everything and it's kind of like a referee.

‫It's like, hey, hey, hey, you can't store things this way.

‫Hey, hey, hey, don't do this.

‫I am going to enforce very specific rules on you.

‫It's like if you took an Excel sheet and you made it a bit smarter, well, this software says I'm going

‫to follow a model.

‫Whatever model that is, it can differ between the database softwares.

‫And I'm going to enforce these rules for you and I'm going to use school as a way for you to talk to

‫me, and I'm going to make sure that your database is safe and secure and that I manage it the correct

‫way.

‫So if we look at what a database management software system can do while we're talking about create,

‫read, update or delete crud operations, OK, let's take a step back here.

‫What do I mean by that?

‫Well, because your database management software is between Ezekial and your database, it's basically

‫the one that's saying, OK, you want to create a database, let's create you a database.

‫OK, you want to create some data.

‫Let me put some data in your database, OK?

‫You want to read some of the data.

‫You want to send me an actual query?

‫Well, I'll give you back the right data.

‫All you want to update something.

‫There's some data in there that doesn't match your expectations.

‫Cool.

‫I'll do that for you.

‫And it can even delete some stuff.

‫OK, we accidentally added a student that isn't going to be part of the school.

‫Let's quickly remove them from the system, create, read, update, delete.

‫But this is an acronym that you will often hear when talking about school and databases, because this

‫is the bulk of what school is going to do for you when you talk to your database management software.

‫And this is the bulk of what the database management software intends to do for you.

‫But on top of that, I talked about the database management software doing a bit more.

‫A database management software not only allows you to do those CRUD operations, but what it's also

‫going to do is it's going to manage your data.

‫It's going to make sure that it's saved in the right place, is going to make sure that it knows on

‫what hard drives is going to put what it's going to secure your data.

‫It's going to make sure that not everyone can touch them.

‫It's going to put in place the right security policies and the right permissions, and it's even going

‫to do something called transaction management.

‫This is something fairly complicated that we're going to get into later.

‫But transaction management is basically like, hey, I want to update something and someone else wants

‫to update something.

‫And they're updating the exact same thing at the same time, while the database management software

‫is going to basically say, oh, something happened here, I'm going to quickly undo the change because

‫that's not what we meant to do.

‫It's going to do way more complex scenarios.

‫It's going to handle those for you.

‫Database management software is basically there to guarantee that your data is always going to stay

‫safe and always going to be accessible.

‫Basically, when we used to build our own custom software, what could happen?

‫Well, some developer could push a change and it could corrupt some data or could do something wrong

‫in a certain operation.

‫And some specific record of a user could go missing record meaning like a specific part of data, like

‫you had a user's address.

‫And when we built the custom software, remember the file processing systems, let's say a developer

‫committed a piece of code that was supposed to update your address and something went wrong there because

‫a database management software is removed from that custom built.

‫And it has one sole responsibility.

‫We're always guaranteed that is going to do these things to the best of its abilities and not the rigorously

‫tested.

‫So this database management software is very good at doing these tasks, both the CRUD operations as

‫well as the security management, and making sure that your data and the people that are interacting

‫with your data do the right things.

‫That is very, very, very key to a database management software.

‫And that is what makes it so powerful because it has a sole responsibility to maintain your database,

‫maintain your data.

‫So who is making database software?

‫Well, Microsoft has SQL Server.

‫IBM has a couple of solutions.

‫We all know Maisky well fairly well.

‫There is Oracle out there.

‫And some of you may have heard of PostgreSQL, which is an open source variation of a database management

‫software.

‫But these are the companies that basically the biggest companies that make database software and they

‫all make it slightly different from each other.

‫You see, each and every one of these companies makes a database software that is, in essence going

‫to maybe follow the relational model or maybe follow some other model of storing data.

‫But they also have different features that they're all trying to compete with each other.

‫So when we talk about MySQL versus what Microsoft brings out, which is ask you all server, they're

‫both using well, for us to talk to it, but they may have slightly different features to kind of up

‫you.

‫Hey, we do this slightly better here.

‫We do transaction management a bit better.

‫Hey, we do security a bit better or we have the best this or that.

‫They, in essence, compete with each other on features.

‫But at the end of the day, there is a core to them.

‫Well, and a certain model of storing data.

‫So, again, what can it do?

‫Well, we talked about the database management software managing the database and all of these players

‫competing with each other in order to allow you all to talk to the software.

‫Right.

‫They all have slightly different variations of skill.

‫They could add some special little things in there.

‫But what we are going to focus on is the core of a school.

‫We want to give you the toolset and the core of the language to be able to go to any of these vendors

‫and be functional.

‫Sure.

‫In each and every one of these, you may need to learn some of the tips and tricks that go with the

‫software because each of these softwares are different.

‫But the baseline of a school is abstracted away from this software.

‫This software is supposed to understand the school and school is supposed to talk to the software.

‫So even if the software is a bit different between these, they all do the same thing.

‫At the end of the day, they do the CRUD operations, the security, the management, and they may all

‫do it slightly differently.

‫But we are going to give you the foundation to be able to interact with any of these.

‫And that is what is so powerful and we're going to do that through school.

‫So if I were to take a database management system and I work to put it in a simple analogy, because

‫analogies are so powerful, let's say that your database management software was a chef and that school

‫was the customer and that the database was a type of cooking.

‫Well, if the database management software is a chef, we all know that chefs do things differently.

‫You can go to three restaurants, you can order the exact same dish, the exact same pizza, margherita,

‫spaghetti Bolognese, a steak.

‫And each and every one of these chefs may do it slightly differently.

‫So each chef has their own, quote unquote, database of cooking, and they may all store the data in

‫their head slightly differently.

‫They'll do steps differently.

‫They'll do this differently, that differently.

‫But at the end, when you ask them to make you a pizza, you are going to get a pizza.

‫I hope that makes a bit of sense.

‫And if we were to stretch that analogy a bit further and you asked the chef for a recipe, you ask the

‫chef, OK, how are you going to do this?

‫If we looked into that, every chef is going to do their recipe a bit differently.

‫They're going to write down steps differently.

‫Each of them thinks differently.

‫And the same is true for a database management software.

‫Each and every one of these interacts differently with the database, interact differently with how

‫they're going to store the data, what hard drives they're going to use, where they're going to put

‫certain files and how they're going to take your query, make me a pizza and how they're going to process

‫that to give you the pizza.

‫That really simplifies the way that we have to look at this, because a database management software

‫is basically the one interacting with both ends.

‫If we took this and we put it at a 10000 foot view.

‫A user is interacting with Eskil and is firing some kind of query and the database management system

‫is interacting with a certain database, it can store multiple databases.

‫You can have databases for multiple, multiple reasons.

‫You can have a school database.

‫You can have a recipe database.

‫And the database management system is just storing these.

‫And then at the hardware level, some hard drive or multiple hard drives or multiple systems are storing

‫the data for you.

‫And the database management system is taking your query and figuring out, OK, I need to talk to this

‫database and I need to go to this hard drive to get the data.

‫And this is how I need to break it down.

‫That's basically how it looks from a high level view.

‫Now, on the Internet, you may see our DBMS, so DBMS stands for database management software and database

‫management software is the general term for a software that is going to manage your databases.

‫But then the R portion, we've already spoken a little bit about the relational model and what the relational

‫model is in a very, very brief way.

‫We'll dive deeper into that as we go along.

‫But when you see RDBMS, you're looking at a database management software that's specializing in relational

‫databases.

‫So it's focusing on one single model.

‫And this one single model was developed by a developer at IBM in the early 80s and then taken by two

‫of his colleagues who invented the original version of school, as well as the very first database management

‫software.

‫They took his ideas and basically built the very first version of school in the very first version of

‫a database management software.

‫But because they were following the relational model and because we were already spoken about the database

‫management software being your referee, being your security, implementing the specific rules that

‫you need to follow.

‫Edgar Chod, the person who came up with the relational model, as well as the database management system,

‫wrote 13 rules that needed to be followed in order for a database management software to be considered

‫a relational database management software.

‫He coined the 13 rules of.

‫Now, we're not going to go into the specifics of them because they're very much at a high level understanding.

‫They're basically rules that need to be followed to build a database management software.

‫They are the rules that the database management software is going to enforce on you when you get an

‫error, when you're trying to do something that doesn't follow these rules.

‫That's what the database management software is doing.

‫It's following these rules in order to give you some constraints and give you a way to save in a relational

‫way.

‫And when we see a relational way, we're talking about the relational model.

‫We're talking about storing things in tables and columns and rows and enforcing that these rules are

‫followed.

‫The database management software is going to enforce them.

‫So now that we know so much about what a database model is and how a database management system is going

‫to be your connecting piece, your referee, your middleman in terms of getting data into the system

‫and pulling data out and enforcing all of these rules, let's take a closer look at this relational

‫model and how we are going to store data so that we can form a full picture of, OK, this is a database.

‫This is my database management software, and this is the model I'm going to follow.

‫This is how I'm going to store my data.

‫And once we have that, once we have that full picture, we will understand how to use ask you well

‫to interact with software like Oracle, like PostgreSQL, like MySQL to store and retrieve data.

‫Now, that being said, there are multiple models out there you can follow.

‫But each database management software worth its salt will focus on one single model.

‫You may have heard of terms like NQ Well and other variations of that hierarchical databases and so

‫forth.

‫Don't focus on any of those.

‫We will dive into those individually to explain how they differ from relational models down the line.

‫But right now we really want to slim down and focus solely on the relational model so that we can really

‫get a solid foundation on a single model, a single way of storing data and using Ezekial with that

‫model.

‫And once we have that solid foundation with one model, when you want to expand to different models,

‫it'll be easier than you think.