Updating multiple documents

[Abhishek kumar]

I have to update one of my collection, which is multi document update

Let collection "A"
A: has fields
{"_id", "field1", "field2", "field3"} // I needed to add
field3 in below update() if its not present or just update if its
present

basciDBObject.put("field1","field_value")

updateDate.put("field3","filed_value")

What I did
collection.update(basicDBObject,updateDate,false,true);

On running the command mongo is telling:
multi update only works with $ operators

Kindly help, what am I missing

[Karl Seguin]

multiple updates only work with the $ modifiers: http://www.mongodb.org/display/DOCS/Updating#Updating-ModifierOperations

This is probably what you want:

BasicDBObject updateDate = new BasicDBObject("$set", new BasicDBObject("field3", fieldValue));

If you did what you are trying, without a multi update, it would replace the entire document with {field3: fieldValue}...unlike SQL, updates in MongoDB don't work on individuals fields by default..it works on the entire document (which makes sense when you consider fields are "dynamic").

Karl

[Abhishek kumar]

thanks..