I'm using MongoDB with the Java driver and have a Collection 'Questions' with the following format for each entry:
{
"question" : "How are you?",
"category" : "personal",
"isTrain" : true,
"processed" : true
}
What I want to do is take every entry with both "processed" and "isTrain" equal to true, and I want to set their "processed" value to false. The code in which I'm trying to use for this is:
public void markUnprocessed(boolean isTrain) {
BasicDBObject queryObj = new BasicDBObject();
queryObj.put("processed", true);
queryObj.put("isTrain", isTrain);
BasicDBObject updateObj = new BasicDBObject();
updateObj.put("processed", false);
collection.updateMulti(queryObj, updateObj);
}
Calling this function from my code seems to have no effect, and I'm not sure why. Any help on the matter would be greatly appreciated.
Thanks,
Chris Covert
You need to do a partial using $set, not a full update.
With current statement you would be losing all the other fields.
BasicDBObject updateObj = new BasicDBObject();
updateObj.put("$set", new BasicDBObject("processed", false));
Also note that you should turn on safe writes (using WriteConcern.SAFE) so that your app gets notified of any error from server.
Related
Was trying to change the data type of all values in a specific field, without use of iterators.
Here tid is the field name
I tried running the code in Mongo using
var ch ={"$addFields" : { "tid" : { "$convert":{"input":"$tid" , "to" : 2}}}}
db.test.aggregate(ch);
Where test is my collection
Java Code :
BasicDBObject fieldObject = new BasicDBObject();
fieldObject.put("$convert",new BasicDBObject().append("input",
"$tid").append("to", 2));
BasicDBObject addField = new BasicDBObject("$addFields",new
BasicDBObject("tid",fieldObject));
System.out.println(addField);
List<BasicDBObject> options = new ArrayList<>();
options.add(addField);
details.aggregate(options);
When I ran the code in mongo command line, the data types are changing from Integer to String.
But no change when I run the same through java code. Is there any issue with my Java Code.
currently I'm trying to learn dealing with MongoDB in Java. I created the collection "plots" and inserted a document:
final Document plotObj = new Document();
plotObj.put(DataKey.PLOT_UUID.getKey(), plot.getUniqueId());
plotObj.put(DataKey.REGION_ID.getKey(), plot.getRegionId());
plotObj.put(DataKey.REGION_WORLD.getKey(), plot.getRegionWorld());
plotObj.put(DataKey.REGION_OWNER.getKey(), plot.getPlotOwner().isPresent() ? plot.getPlotOwner() : null);
plotObj.put(DataKey.PLOT_TRUSTED.getKey(), new BasicDBList().addAll(plot.getTrusted()));
this.collection.insertOne(plotObj);
"DataKey.PLOT_UUID.getKey()" represents a String. "plot.getUniqueId()" represents a java.util.UUID. After inserting this Document, I want to query it:
public boolean hasPlot(UUID plotId){
final BasicDBObject query = new BasicDBObject(DataKey.PLOT_UUID.getKey(), new BasicDBObject("$eq", plotId));
return this.collection.find(query).iterator().hasNext();
}
However this methods always returns false event though the Document was successfully inserted.
Maybe this problem can be fixed with ease but nevertheless: thanks in advance! :)
According to the documentation you don't need the $eq
just write
new BasicDBObject(DataKey.PLOT_UUID.getKey(), plotId));
Here is the sample document of my MongoDB:
user:{
_id:1,
name:'xyz',
age:12,
mobile:21321312,
transaction:[{
trans_id:1,
prod:'a',
purchasedAt:ISODate("2015-02-01"),
},
{
trans_id:2,
prod:'b',
purchasedAt:ISODate("2015-02-01")
},
{
trans_id:3,
prod:'c',
purchasedAt:ISODate("2014-11-24")
}]
,...
}
My query looks like:
db.user.find({transaction:{$elemMatch:{prod:'a', purchasedAt:ISODate("2015-02-01")}}, transaction:{$elemMatch:{prod:{$nin:['b','c']}, purchasedAt:ISODate("2015-02-01")}}}).count()
I am trying to get the user count who have purchased product 'a' on date "2015-02-01" but not have purchased product b & c on same day.
So while trying to do this in Java with the query:
coll.find(new BasicDBObject().append("transaction", new BasicDBObject("$elemMatch", new BasicDBObject("prod", 'a').append("purchasedAt", Date))).append("transaction", new BasicDBObject("$elemMatch", new BasicDBObject("prod", new BasicDBObject("$nin",['b','c'])).append("purchasedAt", Date)));
I have also tried:
coll.find(new BasicDBObject("transaction", new BasicDBObject("$elemMatch", new BasicDBObject("prod", 'a').append("purchasedAt", Date))).append("transaction", new BasicDBObject("$elemMatch", new BasicDBObject("prod", new BasicDBObject("$nin",['b','c'])).append("purchasedAt", Date)));
where Date is "2015-02-01" in util.Date object.
I found out that Java ignores the $in part of the query, i.e. it ignores {transaction:{$elemMatch:{prod:'a', purchasedAt:ISODate("2015-02-01")}} & performs only $nin part.
I found out it by DBCursor object.
Here's the output of the cursor:
Cursor: Cursor id=0, ns=mydb.user, query={ "transaction" : { "$elemMatch" : { "prod" : { "$nin" : [ "b" , "c"]} , "purchasedAt" : { "$date" : "2015-02-01T00:00:00.000Z"}}}}, numIterated=0, readPreference=primary
Because of this my result is inaccurate. I wonder why the exact same query works well in Mongo shell but doesn't with Java API. Is there anything wrong with my query structure?
My guess is that this question is now moot, but, if you still do not consider it answered, are you looking for the "$not" operator, which can check for non-existance sort of.
I need two to add new items to the existing data in mongo db.
This is mongo db I have the following data.
{
"_id" : ObjectId("53ce11e7d0881d32d9fa935f"),
"name" : "massive riots",
"lastFeachedTime" : "Jul 15, 2014 12:55:27 PM"
}
Here I have to find the data based on name and the I have to add another two items two it.
Here is my code.
DBObject queryObject = new BasicDBObject().append("name", keyword);
if (null == newFetchTime) {
}
DBObject updateObject = new BasicDBObject();
updateObject.put("nextPageToken", nextPageToken);
updateObject.put("prevPageToken", prevPageToken);
Utils utils = new Utils();
DBCollection collection = utils.getStaging().getCollection("test");
collection.update(queryObject, updateObject, true, false);
But I am do update the existing value get removed and the new data get added.
Can any one tell me how to add the items to the existing data in mongo db.
You want the $set operator in your update. This allows the specified fields to be altered without affecting any of the existing fields in the document, unless the specified field exists in which case that field is overwritten:
DBObject update = new BasicDBObject(
"$set", new BasicDBObject()
.append("nextPageToken",nextPageToken)
.append("prevPageToken",prevPageToken)
);
Works out to the equivalent in shell:
{ "$set" : { "nextPageToken" : nextPageToken , "prevPageToken" : prevPageToken }}
I would like to get some information which is in a mongoDB except some attributes.
I tried it in cmd and it worked:
db.orders.find({name:"chabeee"},{_id:0, name:1, worksAt:1})
Then I get this result:
{ "name" : "chabeee", "worksAt" : "jobAtBp" }
{ "name" : "chabeee", "worksAt" : "jobAtRE" }
Its okay, but I want to get in a Java Program. How can I do that?
You have to create one additional BasicDBObject, which will be used for pointing out which exact keys to be fetched. And finally the DBCollection#find(DBObject ref, DBObject keys) method has to be invoked in order to pass the desired projection keys.
BasicDBObject query = new BasicDBObject("name", "chabeee");
BasicDBObject keys = new BasicDBObject();
keys.put("_id", 0);
keys.put("name", 1);
keys.put("worksAt", 1);
BasicDBCursor result = collection.find(query, keys);
Then you just have to iterate over the BasicDBCursor and verify the result.
while (cursor.hasNext()) {
System.out.println(cursor.next());
}