Spring boot mongodb : Updating multiple records with custom value using updateMulti

Question

I have a list of records. Each record needs to have 2 fields: temp(temperature in Celcius) and temp_F(temperature in Fahrenheit). temp field is available in mostly all records. But temp_F is missing in most of the records. I want to populate missing temp_F value in the record using the temp value of the record. Here is what i am doing:


Query updateTempFQuery = Query.query(Criteria.where("temp_F").isNull());
        List<TelemetryReport>reports = mongoTemplate.find(updateTempFQuery,TelemetryReport.class);

        for(TelemetryReport report:reports){
            if(report.getTemp() == null) continue;
            Double fahrenHeitValue = new BigDecimal("32").add(new BigDecimal("1.8").multiply(new BigDecimal(report.getTemp().toString()))).doubleValue();
           // temperature in fahrenheit = 32 + 1.8*(temp in celcius)
            Update applyUpdate = new Update().set("temp_F",fahrenHeitValue);
            mongoTemplate.updateFirst(updateTempFQuery,applyUpdate,TelemetryReport.class);
        }

But the code is throwing timeout error because of huge number of records. I want to do it using updateMulti and aggregation or some other similar methods. But i am unable to find some solution. Please help.

smeds · Accepted Answer · 2023-11-14 07:57:31Z

1

You could easily do this with a simple updateMany command.

db.collection.updateMany(
   { "temp_F": { "$exists": false } },
   [
      {
         "$set": {
            "temp_F": {
               "$add": [
                  { "$multiply": [ 1.8, "$temp" ] },
                  32
               ]
            }
         }
      }
   ]
)

With the Java API, the MongoDB command would transform in the following code:

Bson filter = Filters.eq("temp_F", null);
Bson update = Updates.combine(
    Updates.set("temp_F", 
        new Document("$add", Arrays.asList(
            new Document("$multiply", Arrays.asList(1.8, "$temp")),
            32
        ))
    )
);
UpdateResult result = collection.updateMany(filter, update);

answered Nov 14, 2023 at 7:57

smeds

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3 Comments

Kanhaiya Over a year ago

Can u please add import statement for Document ?

smeds Over a year ago

You need to import it via the org.bson.Document package.

Stefania Nov 28, 2024 at 11:45

I have a similar problem: is there no way to let it work with spring boot lib?

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