Is it possible to update existing MongoDB collection with new data. I am using hadoop job to read write data to Mongo. Required scenario is :- Say first collection in Mongo is
{
"_id" : 1,
"value" : "aaa"
"value2" : null
}
after reading data from Mongo and processing data, MongoDB should contain
{
"_id" : 1,
"value" : "aaa"
"value2" : "bbb"
}
If possible, please provide some dummy code.
BasicBSONObject query=new BasicBSONObject();
query.append("fieldname", value);
BasicBSONObject update=new BasicBSONObject();
update.append("$set", new BasicBSONObject().append("newfield",value));
MongoUpdateWritable muw=new MongoUpdateWritable(query,update,false,true);
contex.write(key, muw);
query : is used for providing condition(matching condition).
update : is used for adding new field and value in existing collection.
MongoUpdateWritable: 3rd parameter is upsert value(same as mongodb)
4th parameter is multiple update in many documents in a collection.
Set in Driver class
job.setOutputValueClass(MongoUpdateWritable.class);
I have done it by extending org.apache.hadoop.mapreduce.RecordWriter and overriding write method of this class.
The Mongo-Hadoop Connector doesn't currently suppor this feature. You can open a feature request in the MongoDB Jira if you like.
