mongodbwrite 能不能按字段更新

mongodbwrite writemode isreplace 是直接覆盖整条记录的所有字段。。。。 有没有办法做到 update 某几个字段。。就类似sql 一样。。 update table set filed='' where key=''

Begin by locating the MongoDBWrite implementation and its isreplace writemode handling, then trace how record keys and fields are passed to MongoDB. Done means the issue's requested field-level update behavior is defined and implemented without replacing unspecified fields, with coverage for the chosen update conditions.

Written by the indexing model from the issue text.