Extending Arrays - by storing Objects in the arrays... about nedb HOT 5 CLOSED

Currently, you can put objects in arrays in NeDB. You can then query the array field as usual (that is, query it like a normal field and if any element of the array matches there is a match). The cool thing is that NeDB does deep-equality matching for basic queries on objects, so you can write queries like this:

var db = new Datastore({ inMemoryOnly: true });

db.insert({ a: 5, b: [ 'yo', { bloup: 'blip' }, 7 ] }, function (err, newDoc) {
  // First element of the array, a native type string)
  db.findOne({ b: 'yo' }, function (err, doc) {
    console.log(doc);  // Will return newDoc
  });

  // Second element, an object. Deep equality is used
  db.findOne({ b: { bloup: 'blip' } }, function (err, doc) {
    console.log(doc);   // Will also return newDoc
  });

  // You can also use comparator queries
  db.findOne({ b: { $gt: 6 } }, function (err, doc) {
    console.log(doc);   // Will also return newDoc
  });
});

You don't yet have the power to query for the objects in an array, such as elemMatch, and I may implement that in the future but there is still more basic work to do so I'll close this issue in the meantime :)

Also, note that when I never used arrays containing non-primitive types when I used MongoDB for tldr.io. Instead, I used "foreign keys" (storing an array of ids) and used two queries (one for the main document, the other to get the documents in the array). Mongoose made this process easy.

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I'm guessing that comparator queries on properties of objects in arrays don't work - probably a bit much to ask but this doesn't seem to

{"key": "A","tags": [{"tag": 1},{"tag": 2},{"tag": 3}]}
{"key": "B","tags": [{"tag": 1},{"tag": 3}]}
{"key": "C","tags": [{"tag": 1},{"tag": 2}]}

db.find({"tags": {"tag": {$gt: 2}}},...

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No, but MongoDB doesn't either. That seems like elemMatch to me.

from nedb.

You're probably right there :)

On 21 June 2013 14:06, Louis Chatriot [email protected] wrote:

No, but MongoDB doesn't either. That seems like elemMatch to me.

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Reply to this email directly or view it on GitHubhttps://github.com//issues/32#issuecomment-19814618
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MongoDb does searches in array objects and that's one of its benefits.
For your case right query will be: db.find({"tags.tag": {$gt: 2}})

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