Update document with its value

Question

Need to update a document based its value

var filter = Builders<UnitTravelHistory>.Filter.Empty;
var update = Builders<UnitTravelHistory>.Update.Set(i => i.JobDuration, i.A-i.B)
DBContext.ClientDb.Repository<UnitTravelHistory>(collection).UpdateMany(filter, update);

here A and B are 2 fields in the collection. Can anyone suggest a solution?

score 0 · Answer 1 · answered Mar 12 '20 at 17:18

0

you need to use pipeline updates in order to refer to fields of the document being updated like so:

var pipelineStage = BsonDocument.Parse("{$set:{JobDuration:{$subtract:['$A','$B']}}}");

collection.UpdateMany(
    _ => true, 
    Builders<UnitTravelHistory>.Update.Pipeline(new[] { pipelineStage })
);

here's an alternative

answered Mar 12 '20 at 17:18

Dĵ ΝιΓΞΗΛψΚ

5,068
3
13
26

Update.Pipeline not available – user2972244 Mar 13 '20 at 05:42
am using MongoDB.Driver, Version=2.4.3.23, – user2972244 Mar 13 '20 at 07:02
looks like you need at least [driver v2.9](https://mongodb.github.io/mongo-csharp-driver/2.9/apidocs/html/M_MongoDB_Driver_UpdateDefinitionBuilder_1_Pipeline.htm) and server v4.2 – Dĵ ΝιΓΞΗΛψΚ Mar 13 '20 at 09:18
is there any solution with .Driver, Version=2.4.3.23 and mongodb 4 – user2972244 Mar 13 '20 at 10:01
@user2972244 not that I'm aware of. – Dĵ ΝιΓΞΗΛψΚ Mar 13 '20 at 11:34

Update document with its value

1 Answers1