R:使用mongolite更新mongodb中的条目

Question

我有一个mongo数据库,其中包含我要传递给某些R脚本进行分析的信息.我目前正在使用该mongolite包将信息传递mongo给R.

我在每个mongo条目中都有一个字段checkedByR,它是一个二进制文件,指示条目是否已经由R脚本分析.具体来说,我正在通过各自的mongo ID收集mongo条目,在条目上运行脚本,为checkedByR字段分配a 1,然后继续.

为了完整起见,我使用以下请求查询数据库:

library(mongolite)

mongoID <- "1234abcd1234abcd1234"

m <- mongolite::mongo(url = "mongodb://localhost:27017",
                      collection = "collection",
                      db = "database")

rawData <- m$find(query = paste0('{"_id": { "$oid" : "',mongoID,'" }}'), 
                  fields = '{"_id" : 1, 
                             "checkedByR" : 1, 
                             "somethingToCheck" : 1}')

checkedByR <- 1

但是,我无法使用新checkedByR字段成功更新mongo条目.

我意识到包中update存在一个函数mongolite(请考虑:https://cran.r-project.org/web/packages/mongolite/mongolite.pdf),但我无法收集相关示例来帮助我完成更新处理.

任何帮助将不胜感激.

Answer 1

该mongo$update()函数接受一个query和一个update参数。您可以使用query来查找要更新的数据，并update告诉它要更新哪个字段。

考虑这个例子

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

更新

该rmongodb库不再在 CRAN 上，因此以下代码将不起作用

对于更复杂的结构和更新，您可以执行以下操作

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()

有关更多详细信息，请参阅mongodb 更新文档