R :Opdatering af en post i mongodb ved hjælp af mongolite

mongo$update() funktion tager en query og en update argument. Du bruger query for at finde de data, du vil opdatere, og update for at fortælle det, hvilket felt den skal opdatere.

Overvej dette eksempel

library(mongolite)
    
## create some dummy data and insert into mongodb
df <- data.frame(id = 1:10,
  value = letters[1:10]
)
    
mongo <- mongo(collection = "another_test", 
  db = "test", 
  url = "mongodb://localhost")
    
mongo$insert(df)
    
## the 'id' of the document I want to update
mongoID <- "575556825dabbf2aea1d7cc1"
    
## find some data
rawData <- mongo$find(query = paste0('{"_id": { "$oid" : "',mongoID,'" }}'), 
  fields = '{"_id" : 1, 
  "id" : 1, 
  "value" : 1}'
)
    
## ...
## do whatever you want to do in R...
## ...

## use update to query on your ID, then 'set' to set the 'checkedByR' value to 1

mongo$update(
  query = paste0('{"_id": { "$oid" : "', mongoID, '" } }'),
  update = '{ "$set" : { "checkedByR" : 1} }'
)

## in my original data I didn't have a 'checkedByR' value, but it's added anyway

Opdatering

rmongodb biblioteket er ikke længere på CRAN, så nedenstående kode virker ikke

Og for mere komplekse strukturer og opdateringer kan du gøre ting som

library(mongolite)
library(jsonlite)
library(rmongodb)  ## used to insert a non-data.frame into mongodb
    
## create some dummy data and insert into mongodb
lst <- list(id = 1,
  value_doc = data.frame(id = 1:5,
  value = letters[1:5],
  stringsAsFactors = FALSE),
  value_array = c(letters[6:10])
)
    
## using rmongodb
mongo <- mongo.create(db = "test")
coll <- "test.another_test"
    
mongo.insert(mongo, 
  ns = coll, 
  b = mongo.bson.from.list(lst)
)
    
mongo.destroy(mongo)

## update document with specific ID
mongoID <- "5755f646ceeb7846c87afd90"
    
## using mongolite
mongo <- mongo(db = "test", 
  coll = "another_test", 
  url = "mongodb://localhost"
)
    
    
## to add a single value to an array
mongo$update(
  query = paste0('{"_id": { "$oid" : "', mongoID, '" } }'),
  update = '{ "$addToSet" : { "value_array" :  "checkedByR"  } }'
)
    
## To add a document  to the value_array
mongo$update(
  query = paste0('{"_id": { "$oid" : "', mongoID, '" } }'),
  update = '{ "$addToSet" : { "value_array" : { "checkedByR" : 1} } }'
)
    
## To add to a nested array
mongo$update(
  query = paste0('{"_id": { "$oid" : "', mongoID, '" } }'),
  update = '{ "$addToSet" : { "value_doc.value" :  "checkedByR" } }'
)
    
rm(mongo); gc()

se mongodb-opdatering dokumentation for yderligere detaljer