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Welcome to the section of the course on utilizing databases with Python and flask we now understand

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how to grab user information through forms with flask.

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Well we're going to do now is Bill on top of this understanding by linking our flask applications to

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a database so we can actually save user information.

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So let's talk about databases just in general.

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We're going to be using Escudo or sequel databases and they allow us to store data in a tabular format

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essentially a really large Excel spreadsheet where there's an index columns 0 0 0 1 2 and that's a numeric

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column for every row.

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And then we have values for each column.

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So for example we can have a name column for name of a puppy the breed of the puppy and then the eye

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color of the puppy and each individual row represents a user or a single data point that typically when

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you're working with any Escudo or sequel database you're actually going to need to learn sequence statements.

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So sequel stands for structured query language.

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And that's actually it's own syntax in order to query essentially ask the database for information back

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and that sort of syntax looks something like this.

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Select Asterix from puppies maybe puppies is the name of the table and so on.

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Now luckily with the aid of some useful libraries we're going to be able to use pure python.

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So you don't actually need to learn the structure to create language in order to have a database working

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if your flask application instead will be able to do very similar commands through python.

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So even though we're using as well with our database and our flask application we don't actually need

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to learn the structure language syntax that goes along for typical Escuela database.

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Instead we'll be doing that all through python making our lives a lot easier.

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Now Python and Flast can connect to a variety of sequel database engines.

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So sequel comes in many flavors so to speak including post sequel My sequel sequel light Microsoft sequel

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server and a lot more we're going to be using sequel lite.

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It's a really simple as cool database engine that comes a flask and can handle all our needs and as

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quick point you've probably heard me say both sequel and Eskew all it's really up to you how you prefer

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to say it.

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I sometimes switch back and forth.

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So just keep that in mind.

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So sequel lite despite its name it can actually scale quite well for basic applications.

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If you're running a web application that gets around 100000 hits per day sequela I can handle any issues

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and don't think of a hundred thousand as some sort of hard cap limit.

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It's just a kind of upper limit as far as what you should expect sequel like to be able to handle.

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It's not a hard cap at hundred thousand hits and over it's going to stop working.

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It's just a general range of what it can do.

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So that's pretty good scale.

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Now to get a python flask and a skill together we're going to need what's known as an o r.m and that's

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an object relational mapper.

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Essentially something that allows us to convert Python code to those sequel commands that we talked

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about earlier.

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So as I just mention mentioned or M is going to allow us to directly as Python instead of a sequel syntax

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to create edit update and delete from our database.

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And the most common or M for Python is called sequel alchemy flask sequel.

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Alchemy is an extension off of that that actually allows for an easy connection of flask with sequel

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alchemy.

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So at the end of the day you can see that we simply have layers of abstraction.

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We have the CULE database and then on top of that we're going to abstract further with Python's sequel

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alchemy and then on top of that we have a higher level abstraction called flask sequel alchemy.

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So we're really going to be working on a flat sequel alchemy which is going to allow us to very easily

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connect Python code inside of a flask application to create a sequel database and then we can create

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new rows in that database update the zeros delete those rows and so on.

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So in order to do that you need to actually install flask sequel alchemy.

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It's already in the requirements of text files if you using that you're good to go.

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But in case you haven't used that you can just say Pipp install flask sequel alchemy.

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And you can just do a google search for a flask of alchemy to check out their documentation.

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All right so that's a very brief introduction to just databases and Python in general.

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Coming up next we're going to have a further discussion on how we actually work with flask in particular

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with sequel alchemy.

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We'll see at the next lecture.