Question

我有这个简单的更新api调用：这是我的文件：

{
        "_id" : ObjectId("577a5b9a89xxx32a1"),
        "oid" : {
                "a" : 0,
                "b" : 0,
                "c" : NumberLong("1260351143035")
        },
        "sessions" : [
                {

                }
        ]
}

然后我尝试在会话数组中插入1个元素：

db.getCollection('CustomerInfo').update({"oid.c":1260351143035},{$push:{"sessions.$.asessionID":"test123"}})

但我得到了这个错误：

WriteResult({
        "nMatched" : 0,
        "nUpserted" : 0,
        "nModified" : 0,
        "writeError" : {
                "code" : 16837,
                "errmsg" : "The positional operator did not find the match needed from the query. Unexpanded update: sessions.$.asessionID"
        }
})

使用$ set即可获得相同的错误

Answer 1

如错误所示，

＆＃34;位置操作员未找到查询所需的匹配项。未更新的更新：会话。$。asessionID＆＃34;，

如果the array to be updated is also part of the query，位置运算符将起作用。在您的情况下，查询仅涉及嵌入的文档oid。在您的情况下使用的最佳更新运算符是 $set 。

您可以在查询中包含sessions数组，例如：

db.getCollection('CustomerInfo').update(
    { 
        "oid.c": 1260351143035,
        "sessions.0": {} // query where sessions array first element is an empty document
        /* "sessions.0": { "$exists": true } // query where sessions array first element exists */
    },
    {
        "$set": { "sessions.$.asessionID": "test123" }
    }
)

Answer 2

正如 documentation 所说，您可以执行以下操作：

#toy df
set.seed(1)
df <- data.table(
  date = rep(seq(as.Date("2020-01-01"),as.Date("2020-01-05"),by="day"),each=6),
  k = rep(c("A.mean","A.median","A.min","B.mean","B.median","B.min"),5),
  v = runif(30,0,50)
  ) %>%
  pivot_wider(names_from = k, values_from = v)

df %>% head

  date       A.mean A.median  A.min B.mean B.median B.min
  <date>      <dbl>    <dbl>  <dbl>  <dbl>    <dbl> <dbl>
1 2020-01-01   13.3     18.6 28.6    45.4      10.1 44.9 
2 2020-01-02   47.2     33.0 31.5     3.09     10.3  8.83
3 2020-01-03   34.4     19.2 38.5    24.9      35.9 49.6 
4 2020-01-04   19.0     38.9 46.7    10.6      32.6  6.28
5 2020-01-05   13.4     19.3  0.670  19.1      43.5 17.0 

#pivot longer by group prefix
df %>%
  select(date,matches("A\\.")) %>%
  rename_with(~str_replace(.x,"A\\.","")) %>%
  mutate( k = "A") %>%
  bind_rows(
    df %>%
      select(date,matches("B\\.")) %>%
      rename_with(~str_replace(.x,"B\\.","")) %>%
      mutate( k = "B")
  )

   date        mean median    min k    
   <date>     <dbl>  <dbl>  <dbl> <chr>
 1 2020-01-01 13.3    18.6 28.6   A    
 2 2020-01-02 47.2    33.0 31.5   A    
 3 2020-01-03 34.4    19.2 38.5   A    
 4 2020-01-04 19.0    38.9 46.7   A    
 5 2020-01-05 13.4    19.3  0.670 A    
 6 2020-01-01 45.4    10.1 44.9   B    
 7 2020-01-02  3.09   10.3  8.83  B    
 8 2020-01-03 24.9    35.9 49.6   B    
 9 2020-01-04 10.6    32.6  6.28  B    
10 2020-01-05 19.1    43.5 17.0   B

mongodb开始简单$ push位置运算符没有找到查询所需的匹配项

2 个答案: