Querying in Hyperledger Composer

Question

When I try to make the query:

query PapersFromAPoll
{
    description: "retrieve all the papers from a poll"
    statement:
         SELECT org.acme.democracity.Paper 
          WHERE(poll.pollId == _$id)
}

I am not able to get any rows, here is the fragment where I make this query:

return query('PapersFromAPoll',{id : count.poll.pollId})

It is strange because when I erase the WHERE statement and I make a simple query without any parameters it works perfectly.

Paper and Poll in model.cto file:

asset Paper identified by paperId {
    o String paperId
    o String[] fields
    --> Poll poll  //Paper related with a poll
}

asset Poll identified by pollId {
    o String pollId
    o Ask[] asks
}

TheOkayCoder · Accepted Answer · 2017-10-26T14:18:29.707

5

query PapersFromAPoll
{
  description: "retrieve all the papers from a poll"
  statement:
    SELECT org.acme.democracity.Paper 
      WHERE(poll == _$pollId)
}

So you can filter by the Poll asset by giving a reference to that Poll asset. When you try to query with the pollId it will have to be a reference to the resource resource:org.acme.democracity.Poll#{insert_id}

edited Oct 26 '17 at 14:18

answered Oct 26 '17 at 13:46

TheOkayCoder

127
7

You´re right, I've updated the question by adding Poll and Paper models, so you can see why I'm using poll.pollId. That's because Paper has a Poll field within. – Santiago de Diego Oct 26 '17 at 13:52
I have updated by answer above, hope this helps more! – TheOkayCoder Oct 26 '17 at 14:22
It seems that it´s working. Now I can assure it´s retrieving the row but I get the error message: `Error: Object with ID 'pollId:poll1111' in collection with ID 'Asset:org.acme.democracity.Poll' does not exist` – Santiago de Diego Oct 26 '17 at 14:32
I saw it´s a problem ahead this part so I´ll try to fix it by myself, thanks for your help! – Santiago de Diego Oct 26 '17 at 14:53

Querying in Hyperledger Composer

1 Answers1