Forum | Appery.io

I am trying to use MongoDB's projection feature to rename a field that I am returning from a query as described near the end of http://docs.mongodb.org/manual/refere...

In the example that is provided in that document, the field "copies" is renamed to "copiesSold" in the result.

I have created a test table with the default columns and a string column named "name". It can be seen in the attached screenshot.

When I use projection without the renaming feature, everything works as expected:

precurl -X GET -H "X-Appery-Database-Id: 54011bace4b055c018db1489" -G --data-urlencode 'proj={"name":1}' https://api.appery.io/rest/1/db/collections/projectme

Response: [{"_id":"54011bd9e4b055c018db148d","name":"hello"}]/pre

However, if I try to rename the column the projection fails silently and omits the requested column, but still returns the "_id" column.

precurl -X GET -H "X-Appery-Database-Id: 54011bace4b055c018db1489" -G --data-urlencode 'proj={"new_name":"$name"}' https://api.appery.io/rest/1/db/collections/projectme

Response: [{"_id":"54011bd9e4b055c018db148d"}]/pre

Eventually I would like to do more than just rename columns, but actually use the dot notation to access members of an embedded document, but for the test case I am simply using the feature to rename a field.

Hi -

Thanks for pointing on this issue, we'll investigate this case and we'll let you know when have more information from developers team.

Hi axkrishnan,

Currently Appery.io support only restriction in return object:
You can read more here:

http://devcenter.appery.io/documentat...

Also you can read about it on mongo DB: http://docs.mongodb.org/manual/tutori...

I see you use mongo db "$project (aggregation)" that's not currently supports by Appery.io.

http://docs.mongodb.org/manual/refere...

Regards.

Ok thanks. That's too bad, it would be a handy feature. I wish the documentation was more clear on exactly which mongo features are and aren't supported, because I've definitely used a few mongo features that aren't mentioned in the docs but still works, so I incorrectly assumed that this would too.

You can go ahead and mark this question as resolved for now.

Hello Axkrishnan,

Thank you for the update.