如何在MongoDB中更新字符串的子集? [英] How to update subset of a string in MongoDB?

问题描述

我想更新monogdb中字符串的以下子集

I want to update the following subset of a string in monogdb

Collection: Paper
Field: URL

Document Current: 
   Name : House
   URL : www.home.com/300x300
Document Updated
   Name : House
   URL : www.home.com/600x600

我已经尝试过了，但是似乎不起作用:

I have already tried this but it doesn't seem to be working:

db.Paper.find({Name:"House"}).forEach(function(e,i) {
    e.URL=e.URL.replace("300","600");
    db.Paper.save(e);
});

有什么想法吗?

推荐答案

您可以使用以下聚合之一来查询和更新:

You can use one of the following aggregations to query and update:

db.test.aggregate( [
  {
      $match: {
           url: { $regex: "300x300" }
      }
  },
  { 
      $addFields: { 
          url: { $split: [ "$url", "300" ] } 
      } 
  },
  { 
      $addFields: { 
          url: { 
              $concat: [ 
                        { $arrayElemAt: [ "$url", 0 ] }, 
                        "600", 
                        { $arrayElemAt: [ "$url", 1 ] }, 
                        "600", 
                        { $arrayElemAt: [ "$url", 2 ] }
              ] 
          }
      }
 }
] ).forEach( doc => db.test.updateOne( { _id: doc._id }, { $set: { url: doc.url } } ) )

使用 MongoDB 4.2 + 版本，您可以使用

With MongoDB version 4.2+ you can specify the aggregation instead of an update operation with updateMany:

db.test.updateMany(
  { 
      url: { $regex: "300x300" }
  },
  [
    { 
      $addFields: { 
          url: { $split: [ "$url", "300" ] } 
      } 
    },
    { 
      $addFields: { 
          url: { 
              $concat: [ 
                        { $arrayElemAt: [ "$url", 0 ] }, 
                        "600", 
                        { $arrayElemAt: [ "$url", 1 ] }, 
                        "600", 
                        { $arrayElemAt: [ "$url", 2 ] }
              ] 
          }
      }
    }
  ] 
)

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