CODEWITHSUNDEEP
node.jsmongodbmongoosemongodb-query
Gank
Gank

Reputation: 4667

How to get only one item of a subdocument in mongoose?

ASchema={item:[BSchema]};
ASchema.findOne({item._id=xx})

It gets a array of BSchema, document.item is a array. how to get only one item which _id is xx?

Upvotes: 1

Views: 2185

Answers (2)

Neil Lunn
Neil Lunn

Reputation: 151112

You want the positional $ operator using query projection to just return your matched array element. For Mongoose you can do this:

ASchema.findOne({"item._id": itemId},"item.$",function(err,doc) {
    console.log( doc );
});

Or paired in an object:

ASchema.findOne({"item._id": itemId},{ "item.$": 1 },function(err,doc) {
    console.log( doc );
});

Mongoose supports the shorthand syntax with options like "-fieldname" for field removal which is the same as { "fieldname": 0 }. But you cannot mix inclusion and exclusion with the exception of the root _id field.

Therefore you must specify all of the fields you want to appear when using projection.

See also .select() in the mongoose documentation.

Upvotes: 6

Ray Stantz
Ray Stantz

Reputation: 276

I think your syntax for the query is wrong. Try:

ASchema.findOne({'item._id': xx})

This link is helpful for more examples: http://mongoosejs.com/docs/queries.html

Upvotes: 1

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