couchdb view to select records with key contained in array in document

Question

Trying to get my head around couchdb... first time using a database that isn't SQL.

Trying to figure out how to write a view that returns all users in a particular team....

User docs are like this:

{
   "_id": "e3031a9eb16dd879fbe78b61f800378b",
   "_rev": "3-8aaf2d203b92b684fbd7a27a7dff9108",
   "type": "user",
   "userid": "myuserid",
   "password": "mypassword",
   "email": "myemail@myjob.com",    
   "firstname": "joe",
   "lastname": "smith",
   "org": "companyname",
   "teams": [
       "team2",
       "otherTeam"
       ]
}

You can see the teams array there...

I've been trying stuff like:

function(doc) {
    if (doc.type == 'user') {
        if ((doc.teams.indexOf(searchString) > -1){
            emit(doc.user, doc)
        }
    }
}

But thats not it. I know...

I've had success with other views (like find a user by userid) and calling them with nano like:

db.view('users', 'by_userid', {'key': userid, 'include_docs': true},     
  function(err, body) {
    .. etc
});

But I'm pretty confused as to how to do this one...

db.view('users', 'by_team', {'key': teamName, 'include_docs': true},     
  function(err, body) {
    .. etc
});

Any help greatly appreciated.

score 3 · Answer 1 · answered Dec 18 '15 at 10:32

CouchDb map function creates a view = simple dictionary of key-value pairs. Builtin emit function takes 2 parameters, the first one will be a key in the view, and second one will be a value. So after your map, view 'by_team' should looks like

team2 : {document where team2 is in the teams arr},
team2 : {other document where team2 is in the teams arr},
team2 : {and other document where team2 is in the teams arr},
otherTeam : {document where otherTeam is in the teams arr},
otherTeam : {etc}

And when you query with {'key': 'team2'} db.view just select values with specified key. You also can use {keys : [array, of, keys]} for querying multiply keys

btw you can emit (doc.teams[curTeam], null) and query with {'key': 'team2', 'include_docs': true} this approach will reduce the size of your view if needed.

Thank you very much.. that is all getting a bit clearer now. — Vida, Dec 18 '15 at 15:06
Ok! So the penny finally dropped... When I query a view .. I'm not trying to plug values into the view definition (like in a SQL stored proc).. I'm querying the OUTPUT of the view !! So 'key' is checked against the first column of the output of the view... Doh! Okay.. now I'm gettin it! Thanks again.. — Vida, Dec 18 '15 at 16:50

score 0 · Answer 2 · edited May 23 '17 at 12:15

Just FYI, found the answer via this post:

CouchDb view - key in a list

My code looks like this for the view:

function(doc) {
   if(doc.teams) {
      for (var curTeam in doc.teams) {
        emit (doc.teams[curTeam],doc);
      }
  }
}

And then called like this:

db.view('users', 'by_team', {'key': 'team2'},function(err, body) {
  if (!err) {
    body.rows.forEach(function(doc) {
      console.log(doc);
    });
  }
});

I still don't fully understand it.. but it works... heh... If anyone can explain how 'team2' gets used in the view.. I'd appreciate it..

couchdb view to select records with key contained in array in document

2 Answers2