Remove an array entry in an object using spring data mongodb - mongodb

Question

I recently spent some time trying to use the $pull operator through Spring's Data MongoOperations interface, so I thought it would be nice to share my findings in case anyone bumps into a similar problem.
So here it goes...
I have 2 java POJOs like so :
#Document
public class OutterObject{
private String id;
private String name;
private List<InnerDocument> innerDocs;
//SETTERS - GETTERS Ommited
public class InnerDocument{
private String id;
private String name;
//SETTERS - GETTERS Ommited
This is stored in a Mongo collection like so :
"_id" : "doc2",
"_class" : "OutterObject",
"name" : "doc2",
"innerDocs" : [{
"_id" : "innerDoc21",
"name" : "innerDoc21"
}, {
"_id" : "innerDoc22",
"name" : "innerDoc22"
}]
I'm trying to use the $pull operator in order to remove all objects inside the innerDoc collection having a name value = "innerDoc22".
I know how to accomplish this using the mongo driver like so :
List<String> ids =
Arrays.asList("innerDoc22");
BasicDBObject find = new BasicDBObject();
match.put("innerDocs.name",
BasicDBObjectBuilder.start("$in", ids).get());
BasicDBObject update = new BasicDBObject();
update.put(
"$pull",
BasicDBObjectBuilder.start("innerDocs",
BasicDBObjectBuilder.start("name", "innerDoc22").get()).get());
DBCollection col= mongoOperations.getDb().getCollection("outterObject");
col.update(find , update);
I'm trying to accomplish the same thing using Spring's MongoOperations Interface.
Here is my code using the MongoOperations interface :
List<String> ids = Arrays.asList("innerDoc22");
Query removeQuery = Query.query(Criteria.where("innerDocs.name").in(ids));
WriteResult wc = mongoOperations.upsert(
removeQuery,
new Update().pull("innerDocs.name", "innerDoc22"),
OutterObject.class);
System.out.println(wc.getLastError());
I'm not getting any errors when calling getLastError() the update is simply not done in the database.
I know a similar question has already been asked here but the answer that was given does not use the MongoOperations interface.

Answer 1

After searching a bit and looking at the source code I realized that I needed to pass an InnerDocument object as a second parameter to the pull method so that the spring classes would be able to do the mapping correctly.
As it turns out I can navigate objects while selecting objects (I'm using "innerDocs.name" in the removeQuery) but I cannot (or havent found a way) do the same when updating a document.
Below is how I implemented the query using MongoOperations :
List<String> ids = Arrays.asList("innerDoc22", "innerDoc21");
Query removeQuery = Query.query(Criteria.where("innerDocs.name").in(ids));
WriteResult wc =
mongoOperations.upsert(removeQuery,
new Update().pull("innerDocs",
new InnerDocument("innerDoc22", null)),
OutterObject.class);
System.out.println(wc.getLastError());

Answer 2

You can also use the BasicDBObject instead of the InnerDocument I found this out by accident. By printing out the update object, you can see the actual mongo shell query json, which is super helpful for debugging.
:
Update updateObj = new Update()
.pull("innerDocs", new BasicDBObject("innerDocs.name","innerDoc22"));
System.out.println("UPDATE OBJ: " + updateObj.toString());
results in:
UPDATE OBJ: { "$pull" : { "innerDocs" : { "innerDocs.name" : "innerDoc22"}}}

Answer 3

I tried the solution given by med116 and I had to modify it to work :
Update updateObj = new Update().pull("innerDocs", new BasicDBObject("name","innerDoc22"));
Because otherwise there was no matching object in my array.

Answer 4

in spring data mongo,just like this:
//remove array's one elem
UpdateResult wc = mongoTemplate.upsert(removeQuery,new Update().pull("tags",Query.query(Criteria.where("tag").is("java"))),TestPull.class);
//remove array's multi-elem
UpdateResult wc1 = mongoTemplate.upsert(removeQuery,new Update().pull("tags",Query.query(Criteria.where("tag").in(Arrays.asList("mongo", "netty")))),TestPull.class);

Answer 5

If you simply want to remove an element from array which does not have any other property like name then write the query you wish and
Update update = new Update();
update.pull("Yourarrayname","valueyouwishtodelete");
mongoTemplate.upsert(query,update,"collectionname");

Answer 6

That's my solution - thanks to #ufasoli:
public Mono<ProjectChild> DeleteCritTemplChild(String id, String idch) {
Query query = new Query();
query.addCriteria(Criteria
.where("_id")
.is(id)
.and("tasks._id")
.is(idch)
);
Update update = new Update();
update.set("tasks.$", null);
return template
// findAndModify:
// Find/modify/get the "new object" from a single operation.
.findAndModify(
query, update,
new FindAndModifyOptions().returnNew(true), ProjectChild.class
);
}

Answer 7

This works for me!
UpdateResult updateResult = mongoTemplate.updateMulti(new Query(where("id").is(activity.getId())), new Update().pull("comments", new Query(where("id").is(commentId))), Activity.class);
It will generate:
Calling update using query: { "_id" : { "$oid" : "61f900e7c7b79442eb3855ea"}} and update: { "$pull" : { "comments" : { "_id" : "61fac32e3f9ab5646e016bc8"}}} in collection: activity