MongoDb: add element to array if not exists [duplicate]
You can use $addToSet operator to check exist before append element into array.
db.tags.update( {name: 'sport'}, {$addToSet: { videoIDs: "34f54e34c" } });In this update statement example, mongoDB will find the TAG document which matches name == sport, and then check whether the videoIDs array contains 34f54e34c. If not, append it to the array.
Detail usage of $addToSet please read here.
I didn't test it, but you can try something like:
yourDb.find({ name: "sport", videoIDs: { $in: ["34f54e34c"] } }) .update({$addToSet: { videoIDs: "34f54e34c" }});If you need how: MongoDb in nodeJs implementation, you can start with:
$addToSet operator check for the empty or existing array in document.
db.col_name.update({name :"name_for_match"},{$addToSet : { videoId : "video_id_value"}})