Mongodb remove item from array

问题

I'm trying to remove an element from an array using Java and haven't been successful...

I have a "emailsInApp" collection and inside I have this:

{ "_id" : "750afe", "list" : [ "John@gmail.com", "Mike@gmail.com" ] }
{ "_id" : "711850", "list" : [ "example@gmail.com" ] }

It holds for each id the registered emails.

What I would like to do is: given an id and an email, remove that email from that appId.

This is what I have atm and when I run it it doesn't change the array at all:

DBCollection emailsApp = db.getCollection(EmailsInAppColl);
BasicDBObject queryEmail = new BasicDBObject();
queryEmail.put("_id", appId);
BasicDBObject updateEmailCommand = new BasicDBObject();
updateEmailCommand.put("$pull", new BasicDBObject("list", email));
emailsApp.update(queryEmail, updateEmailCommand, true, true);

Could you point me in the right direction please?

Edit: As reccomended by @Constantine if I debug it this is what I get:

DBCollection emailsApp = db.getCollection(EmailsInAppColl);
queryEmail.put("_id", appId);
DBCursor cursor = emailsApp.find(queryEmail);
System.out.println("######*****"+cursor.next());

In the console:

#####*****{ "_id" : "711850" , "list" : [ "example@gmail.com" , "peanut@gmail.com" , "chewie@gmail.com" , "gold@gmail.com"]}

The search query is correct but it does not remove the item...

回答1:

Try something, like this:

BasicDBObject match = new BasicDBObject("_id", appId); //to match your direct app document
BasicDBObject update = new BasicDBObject("list", email);
coll.update(match, new BasicDBObject("$pull", update));

It should work.

来源：https://stackoverflow.com/questions/17061665/mongodb-remove-item-from-array