azure easy tables custom api - mysql

Question

I read in this post that easy tables can have relational database features like join etc for combining tables while querying data. Unfortunately I haven't been able to find much about how to go about doing this.
In my case i have an easy table user and another called subject choice having userid attribute in common and i need to retrieve information in a mobile service app based on info in both of these tables.
How do I go about this?

Answer 1

You can manipulate the easy tables query from the easy api script editor.
You will see a .json and .js file for each "easy table" you created. There will be a commented table.read function with the same signature as my example below. Uncommenting this function and modifying the content allows any kind of custom manipulation server side.
So to do a "Join" you COULD fetch the records from both tables yourself, and then return a "combined" json object.
Here is an example of fetching the data from the storage and deciding when to return:
table.read(function (context) {
var response = context.execute();
response.then(function (records)
{
console.log("Records Fetched: " , records);
// HERE YOU CAN MESS WITH THE DATA
context.res.status(200).send(records);
context.done();
}, function (error)
{
console.log(error);
context.res.status(500).send(error);
context.done();
});
});

Answer 2

According to your description, I followed this tutorial for getting started with the Easy Tables of Azure Mobile App. In my opinion, Easy Tables could provide you with a simple way to add back-end data storage for your mobile app.
We could wrap the operations to the specific table as follows:
public class UserDataService
{
MobileServiceClient mobileService;
IMobileServiceTable<User> userTable;
public void Initialize()
{
mobileService= new MobileServiceClient("http://<your-mobileapp-name>.azurewebsites.net/");
userTable = mobileService.GetTable<User>();
}
public async Task<User> GetUserAsync(string uid)
{
return await this.userTable.LoolupAsync(uid);
}
public async Task AddUserAsync(User user)
{
await this.userTable.InsertAsync(user);
}
}
easy tables can have relational database features like join etc for combining tables while querying data.
As far as I know, you could add a foreign key in a Easy Table for creating your relationships. But you couldn't retrieve data from multiple tables in a single query. For your scenario, you could invoke the methods UserDataService.GetUserAsync and SubjectChoiceDataService.GetByUserIdAsync to aggregate the data as you expected.