从MongoDB中的键值对列表更新一组文档
让我们创建一个包含文档的集合-
> db.demo227.insertOne({"_id":"101","Name":"Chris"});
{ "acknowledged" : true, "insertedId" : "101" }
> db.demo227.insertOne({"_id":"102","Name":"Bob"});
{ "acknowledged" : true, "insertedId" : "102" }在find()方法的帮助下显示集合中的所有文档-
> db.demo227.find();
这将产生以下输出-
{ "_id" : "101", "Name" : "Chris" }
{ "_id" : "102", "Name" : "Bob" }以下是从键值对列表中更新一组文档的查询-
> var bulkUpdateValue = [{"_id": "101", "Name": "Robert"},
... {"_id": "102", "Name": "Sam"}
...];
> var bulkUpdate = db.demo227.initializeUnorderedBulkOp();
> var updateCounter= undefined;
> for (var i = 0; i < bulkUpdateValue.length; i++){
... updateCounter = bulkUpdateValue[i];
... bulkUpdate.find( {_id: updateCounter._id} ).update( {$set: {Name: updateCounter.Name}} );
... }
> bulkUpdate.execute();
BulkWriteResult({
"writeErrors" : [ ],
"writeConcernErrors" : [ ],
"nInserted" : 0,
"nUpserted" : 0,
"nMatched" : 2,
"nModified" : 2,
"nRemoved" : 0,
"upserted" : [ ]
})在find()方法的帮助下显示集合中的所有文档-
> db.demo227.find();
这将产生以下输出-
{ "_id" : "101", "Name" : "Robert" }
{ "_id" : "102", "Name" : "Sam" }