Add support for $slice in Update.push [DATAMONGO-832]

[spring-projects-issues]

Christoph Strobl opened DATAMONGO-832 and commented

Since mongodb 2.4 the $push operator can be used along with $slice

{ $push: { quizzes: { $slice: -5 } } }

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Reference URL: http://docs.mongodb.org/manual/reference/operator/update/push/

Attachments:

• DATAMONGO_832.patch (11.58 kB)

Issue Links:

• DATAMONGO-812 $pushAll is deprecated since mongo 2.4 move to $push $each

Referenced from: pull request #374

7 votes, 7 watchers

[spring-projects-issues]

Benjamin M commented

It's already supported (at least using Spring data MongoDB 1.4.0.M1):

update = new Update().push(...)
query = new Query().fields().slice(...)

Use that with MongoTemplate: mongoTemplate.updateMulti(query, update, class);

[spring-projects-issues]

Christoph Strobl commented

Assume you got a document like

{
  "_id" : 1,
  "values" : [ "one" ]
}

And an update with $push $each $slice

db.sample.update(
  {"_id" : 1},
  { 
    $push: { "values" : { $each : ["two", "three", "four", "five"], $slice: -2 } }
  }
)

Then the above would push only the last two entries to the document

[spring-projects-issues]

Alexander Suslov commented

Benjamin M solution which you provide is not was expected. It is a projection modifier, while requested one is update modifier. It means that with solution provided by you array will still be unlimited and only will be sliced when fetched. By desired behavior as I can understand (and what required in my case) is not have a limited array in the storage. In the attachment you will find an implemented of this modifier