Clever Geek Handbook

How do I add and remove elements in an array in Mongo using Java?

So, I have an object:

"_id" : 1,
"employee_id" : [2, 3, 4, 5],
"project_name" : "qwerty"

And I want to remove from "employee_id"

array [3, 5]

and add a new array [13, 6, 8]

. And the result will be:

"_id" : 1,
"employee_id" : [2, 4, 13, 6, 8],
"project_name" : "qwerty"

I am using this Java code:

DB database = mongoClient.getDB("employee_service");
DBCollection collectionProject = database.getCollection("project");

DBObject query = new BasicDBObject();
query.put("_id", project.getId());

DBObject projectMongoObject = new BasicDBObject();
projectMongoObject.put("project_name", project.getProjectName());

//something
collectionProject.update(query, projectMongoObject);

So how to set to a projectMongoObject

new array and delete an array?

+3


source to share


1 answer


Use $ pullAll to remove fields, and a combination of $ push and $ each to add new fields to the array.



   DBObject query = new BasicDBObject();
   query.put("_id", project.getId());   
   DBObject projectMongoObject = new BasicDBObject();
   projectMongoObject.put("$set", new BasicDBObject("project_name",
                                                     project.getProjectName()));
   projectMongoObject.put("$pullAll", 
                          new BasicDBObject("employee_id", new int[]{3,5}));
   collectionProject.update(query, projectMongoObject);
   projectMongoObject = new BasicDBObject();
   projectMongoObject.put("$push", 
                            new BasicDBObject("employee_id",
                                              new BasicDBObject("$each",
                                                            new int[]{13,6,8})));
   collectionProject.update(query, projectMongoObject);
+2


source






More articles:


All Articles