Update elements inside a array MongoDB using Java

Question

A sample JSON Document

{
"_id" : "ab85cebc-8c7a-43bf-8efc-1151ccaa4f84",
"address" : {
    "city" : "Bangalore",
    "postcode" : "560080",
    "countrycode":"in",
    "street" : "SADASHIVNAGAR,SANKEY TANK RD"
},
"brand" : "Shell",
"prices" : [ 
    {
        "fuelType" : "DIESEL",
        "price" : 52.7
    }, 
    {
        "fuelType" : "PETROL",
        "price" : 67.05
    }
]
}

I have around 20 docs for brand:Shell with different location in and around Bangalore.
For all those I have to update Diesel and Petrol price.

Say current DIESEL and PETROL prices are 57.9 and 71.4 respectively?

How do I update all document with these latest price using JAVA (using Eclipse IDE)

Code (in complete)

public class UpdateGasstationFuelPrice {

public static void main(String[] args) {
    MongoClient client = new MongoClient("localhost",27017);
    MongoDatabase db = client.getDatabase( "notes" );

    MongoCursor<Document> cursor = db.getCollection( "gasstation" ).find( new BasicDBObject( "address.countrycode","in" )
        .append("address.city","Bangalore")
        .append("brand","Shell")).iterator();

    if (cursor.hasNext()){
        Document doc = cursor.next();
    }
    client.close();
}
}

Update with Query

  db.getCollection("gasstation").update({"address.countrycode":"in","address.city":"Bangalore","brand":"Shell"},   
            //Query to get the position
            { 
              "prices":  { $exists: true }  
            },
            // Use the positional $ operator to update specific element (which matches your query    
            { 
              $set: 
                  { 
                    //set value specific to elements field/key
                    "prices" : [
                        {
                            "fuelType" : "DIESEL",
                            "price" : 502.7
                        }, 
                        {
                            "fuelType" : "PETROL",
                            "price" : 607.05
                        }
                      ] 
                  } 
            } 
        );

Can you show us what you have tried so far to update? Have you read docs of updating array fields? — Shrabanee
– Shrabanee, Commented Jun 15, 2016 at 6:18
Possible duplicate of Updating a specific key/value inside of an array field with MongoDB — Shrabanee
– Shrabanee, Commented Jun 15, 2016 at 6:28
@titi23 This query i have written to fetch the doc from MongDB MongoCursor<Document> cursor = db.getCollection( "gasstation" ).find( new BasicDBObject("address.city","Bangalore") .append("brand","Shell")).iterator(); — Shreyas Rao B
– Shreyas Rao B, Commented Jun 15, 2016 at 6:30
Please add it in the question and try serching in SO. You can find some solution. — Shrabanee
– Shrabanee, Commented Jun 15, 2016 at 6:32

Amol M Kulkarni · Accepted Answer · 2016-06-15 10:50:40Z

1

You cannot updated util you know the position of the element which you want to update.

So basically what you can do is:

You need to query to seek the position.
Use the positional operator and update the array.

db.gasstation.update(    
    //Query to get the position
    { 
      "prices.fuelType":  "DIESEL"  
    },
    // Use the positional $ operator to update specific element (which matches your query    
    { 
      $set: 
          { 
            "prices.$" : 
              //Element/new value to update
               {
                 "fuelType" : "DIESEL",
                 "price" : 999.7
               } 
          } 
    } 
);

If you want just to update only specific field inside the json element embedded in the array you can do as follows:

db.gasstation.update(    
    //Query to get the position
    { 
      "prices.fuelType":  "DIESEL"  
    },
    // Use the positional $ operator to update specific element (which matches your query    
    { 
      $set: 
          { 
            //set value specific to elements field/key
            //i.e. Update documents in an Array
            "prices.$.price" : 999.7 
          } 
    } 
);

Updates based on comments:

db.gasstation.update(    
    //Query to match
    {
      "address.city":"Bangalore",
      "brand":"Shell",
      "countrycode":"in",
      "prices": { $exists: true }
    },
    // Use $set operator & overwrite entire array
    { 
      $set: 
          { 
            //Overwrite value
            "prices" : [
                {
                    "fuelType" : "DIESEL",
                    "price" : 502.7
                }, 
                {
                    "fuelType" : "PETROL",
                    "price" : 607.05
                }
              ] 
          } 
    } 
);

edited Jun 15, 2016 at 10:50

answered Jun 15, 2016 at 6:33

Amol M Kulkarni

21.7k34 gold badges125 silver badges165 bronze badges

Sign up to request clarification or add additional context in comments.

11 Comments

Shreyas Rao B Over a year ago

How do i do it for Petrol and Diesel together and also for 20 documents in a single command? is it possible?

Amol M Kulkarni Over a year ago

@ShreyasRaoB You can frame your query such that it gets all the 20 or more elements and update the same way. Its actually easier further to tweak based on the above mentioned code in your way

Amol M Kulkarni Over a year ago

@ShreyasRaoB: Actually if you are updating both together, why you need to find/ seek positions, you can blindly set both of them like a overwrite. Doesn't it that work for you?

Shreyas Rao B Over a year ago

I am new, Bit confused on how to write query too. I need to use find/ seek position beacuse fuelprice are different for both fuletype. So if one doc contain both DIESEL and PETROL the i have to update prices specificalyy to each one.

Shreyas Rao B Over a year ago

Now it worked!!!! Thanks for letting me know how to solve the problem...

|

Collectives™ on Stack Overflow

Update elements inside a array MongoDB using Java

1 Answer 1

11 Comments

Your Answer

Linked

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

11 Comments

Your Answer

Sign up or log in

Post as a guest

Linked

Related