hello and a very warm welcome to the sub query  heroes course making the world's decentralized  
hello and a very warm welcome to the sub query  heroes course making the world's decentralized  

data more accessible first of all let's  jump in and take a look at what sub query is  
data more accessible first of all let's  jump in and take a look at what sub query is  

it's an open source project that allows developers  to do three main things to index transform  
it's an open source project that allows developers  to do three main things to index transform  

and query substrate chain data to power your  applications you can think of it like a google  
and query substrate chain data to power your  applications you can think of it like a google  

for blockchains where you can search for the data  that you need you can then transform it and then  
for blockchains where you can search for the data  that you need you can then transform it and then  

serve it up to your front end application very  easily and very quickly now what are the problems  
serve it up to your front end application very  easily and very quickly now what are the problems  

subquery is trying to solve first of all query  speed so if you want to grab data from the  
subquery is trying to solve first of all query  speed so if you want to grab data from the  

blockchain now it's actually quite challenging  first of all you may have to spin up your own  
blockchain now it's actually quite challenging  first of all you may have to spin up your own  

node and that can take quite a bit of time  particularly trying to synchronize the data  
node and that can take quite a bit of time  particularly trying to synchronize the data  

secondly once you have a node you need to  be able to connect to it typically via rpc  
secondly once you have a node you need to  be able to connect to it typically via rpc  

connection what sub query does is it provides  this intermediate layer where it will grab the  
connection what sub query does is it provides  this intermediate layer where it will grab the  

data for you the data will then be transformed  and indexed and made available via api this  
data for you the data will then be transformed  and indexed and made available via api this  

makes grabbing the data very easy and very quick  the second problem is around parachain diversity  
makes grabbing the data very easy and very quick  the second problem is around parachain diversity  

for example trying to query data from  different blockchains can be really challenging  
for example trying to query data from  different blockchains can be really challenging  

what parachain diversity does is it allows you to  grab data across different blockchains in a much  
what parachain diversity does is it allows you to  grab data across different blockchains in a much  

simpler fashion let's take a closer look at  this so traditionally the bitcoin blockchain is  
simpler fashion let's take a closer look at  this so traditionally the bitcoin blockchain is  

separate to say the ethereum blockchain however  in the polkadot world different blockchains  
separate to say the ethereum blockchain however  in the polkadot world different blockchains  

are called parachains and they are all  connected together in the polkadot network  
are called parachains and they are all  connected together in the polkadot network  

so for example here you can see bitfrost  and moonbeam and akala for example  
so for example here you can see bitfrost  and moonbeam and akala for example  

these are all parachains that run off the  polka dot system to be able to extract  
these are all parachains that run off the  polka dot system to be able to extract  

information from these different  blockchains what sub query does  
information from these different  blockchains what sub query does  

is it allows you to query across these different  para chains aggregate the data and be able to  
is it allows you to query across these different  para chains aggregate the data and be able to  

perform one simple query so the diagram on the  right you can see here we can quickly find out  
perform one simple query so the diagram on the  right you can see here we can quickly find out  

how much does alice have in her wallet across the  darwinia polkadot and a color substrate blockchain  
how much does alice have in her wallet across the  darwinia polkadot and a color substrate blockchain  

so that's the second advantage that subquery  provides now jumping into the overview of  
so that's the second advantage that subquery  provides now jumping into the overview of  

the course we first take a look at getting  started if we jump into the documentation here  
the course we first take a look at getting  started if we jump into the documentation here  

this follows the quick start guide where there is  a hello world project that you can follow to get  
this follows the quick start guide where there is  a hello world project that you can follow to get  

familiar with subquery to prepare your environment  and to get a project up and running really quickly  
familiar with subquery to prepare your environment  and to get a project up and running really quickly  

once you've had a taste of how things work  we then jump into the basics of sub query  
once you've had a taste of how things work  we then jump into the basics of sub query  

you can see here on the left hand side this covers  for example the manifest file the graphql schema  
you can see here on the left hand side this covers  for example the manifest file the graphql schema  

and the mappings file as well
and the mappings file as well

in module 3 we then look at relationships  
in module 3 we then look at relationships  

what this means is that inside our graphql schema  the very important file where you effectively  
what this means is that inside our graphql schema  the very important file where you effectively  

define the shape of your data and we'll talk  more about what this means in the course  
define the shape of your data and we'll talk  more about what this means in the course  

we explore the one to one the one to  many and the many to many relationships
we explore the one to one the one to  many and the many to many relationships

after that, we look at subquery  project and subquery explorer
after that, we look at subquery  project and subquery explorer

in the top right-hand corner, you'll see projects  
in the top right-hand corner, you'll see projects  

if I click on this subquery project is a place  where you can run your project hosted by subquery  
if I click on this subquery project is a place  where you can run your project hosted by subquery  

explorer is a place where you can search  for other projects created by the community  
explorer is a place where you can search  for other projects created by the community  

you can utilize the projects here you can search  and try to learn how other people have created  
you can utilize the projects here you can search  and try to learn how other people have created  

sub-query projects as well so it's an open  community where projects are being shared  
sub-query projects as well so it's an open  community where projects are being shared  

in module 5 we'll take a look at aggregation what  this means is once we have the data how do we  
in module 5 we'll take a look at aggregation what  this means is once we have the data how do we  

roll it up or sum or add together all  the data to for example get the balance  
roll it up or sum or add together all  the data to for example get the balance  

of a wallet and towards the end in module six  we'll look at tips and tricks on how you can  
of a wallet and towards the end in module six  we'll look at tips and tricks on how you can  

better build your subquery projects so with that  feel free to contact us at the various means  
better build your subquery projects so with that  feel free to contact us at the various means  

down below either on telegram Twitter Linkedin  medium or Github and we hope you enjoy the course
down below either on telegram Twitter Linkedin  medium or Github and we hope you enjoy the course