Uniqueness of a tuple in couchdb query

Question

I am trying to make a query which I haven't been able to yet. My permanent view function is following:

function(doc) { 
    if('llweb_result' in doc){
         for(i in doc.llweb_result){ 
             emit(doc.llweb_result[i].llweb_result, doc);
         }
    }
}

Depending on the key, I filter the result. So, I need this key. Secondly, as you see, there is a for loop. This causes identical tuples in the result. However, I also need to do this for loop to check everything. In here, I just want to know how to eliminate identical tuples?

I am using couchdb-python. My related code is:

result = {}
result['0'] = self.dns_db.view('llweb/llweb_filter', None, key=0, limit = amount, startkey_docid = '000000052130')
result['1'] = self.dns_db.view('llweb/llweb_filter', None, key=1, limit=amount)
result['2'] = self.dns_db.view('llweb/llweb_filter', None, key=2, limit=amount)

As it is understood from key values, there are three different types of keys. I thought that I can extend the 'key' with [doc._id, llweb_result]. I need a key like [*, 2], but I don't know it is possible. Then, use reduce function to group them. This will definitely work, but at this time the problem is how to make a selection query by using only the values [0,1,2].

Edited in 16.08.12

Example for 'llweb_result' property of a couchdb record:

"llweb_result": {
   "1": {
       "ip": "66.233.123.15",
       "domain": "domain.com",
       "llweb_result": 1
   },
   "0": {
       "ip": "66.235.132.118",
       "domain": "domain.com',
       "llweb_result": 1
   }
}

there is only one domain name in one record, but ther could be multiple ips for it. You can consider the record as a dns packet.

I want to group records depending on llweb_result (0,1,2). I will do a selection query for them(e.g. I fetch records which contains '1'). But for the example above, there will be two identical tuples in the result.

Any help will be appriciated.

You should definitely give some more details. Please explain what problem you are trying to solve. And provide some sample doc. — Marcello Nuccio, Aug 16 '12 at 13:22

score 1 · Answer 1 · answered Aug 15 '12 at 00:26

1

If you get duplicate pairs in the query results, it means that you have the duplicate doc.llweb_result[i].llweb_result values in each document.

You can change the view function to emit only one of these values (as the key). One way to do so would be:

function(doc) {
    if ('llweb_result' in doc) {
         distinct_values = {};
         for (var i in doc.llweb_result) {
             distinct_values[doc.llweb_result[i].llweb_result] = true;
         }
         for(var dv in distinct_values) {
             emit(dv, doc);
         }
    }
}

answered Aug 15 '12 at 00:26

behnam

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It is not the thing that I am looking for. – Shnkc Aug 15 '12 at 19:48
1

Okay. So would you please elaborate? – behnam Aug 16 '12 at 06:07

score 0 · Answer 2 · answered Aug 15 '12 at 01:16

I don't know anything about couchdb-python but CouchDB supports either a single key or multiple keys in an array. So, take a look in your couchdb-python docs for how to supply keys=[0,1,2] as a parameter.

Regarding getting just the unique values, take a look at this section of CouchDB The Definitive Guide which explains how to add basically a NOOP reduce, so you can use group=true

Uniqueness of a tuple in couchdb query

2 Answers2