在MongoDB中更新许多文档
要更新许多文档，请使用UPSERT()和UPDATE()。让我们创建一个包含文档的集合-
> db.demo425.insertOne({"Name":"Chris","Age":21});
{
"acknowledged" : true,
"insertedId" : ObjectId("5e74ee4fbbc41e36cc3cae6c")
}
> db.demo425.insertOne({"Name":"David","Age":23});
{
"acknowledged" : true,
"insertedId" : ObjectId("5e74ee56bbc41e36cc3cae6d")
}
> db.demo425.insertOne({"Name":"Chris","Age":21});
{
"acknowledged" : true,
"insertedId" : ObjectId("5e74ee57bbc41e36cc3cae6e")
}
> db.demo425.insertOne({"Name":"Chris","Age":21});
{
"acknowledged" : true,
"insertedId" : ObjectId("5e74ee5cbbc41e36cc3cae6f")
}在find()方法的帮助下显示集合中的所有文档-
> db.demo425.find();
这将产生以下输出-
{ "_id" : ObjectId("5e74ee4fbbc41e36cc3cae6c"), "Name" : "Chris", "Age" : 21 }
{ "_id" : ObjectId("5e74ee56bbc41e36cc3cae6d"), "Name" : "David", "Age" : 23 }
{ "_id" : ObjectId("5e74ee57bbc41e36cc3cae6e"), "Name" : "Chris", "Age" : 21 }
{ "_id" : ObjectId("5e74ee5cbbc41e36cc3cae6f"), "Name" : "Chris", "Age" : 21 }以下是在MongoDB中上载许多文档的查询-
> var b1 = db.demo425.initializeUnorderedBulkOp();
> b1.find( { Name: "Chris" } ).upsert().update(
... {
... $setOnInsert: { id:101},
... $set: { Name: "Robert", Age:23 }
... }
... );
> b1.execute();
BulkWriteResult({
"writeErrors" : [ ],
"writeConcernErrors" : [ ],
"nInserted" : 0,
"nUpserted" : 0,
"nMatched" : 3,
"nModified" : 3,
"nRemoved" : 0,
"upserted" : [ ]
})在find()方法的帮助下显示集合中的所有文档-
> db.demo425.find();
这将产生以下输出-
{ "_id" : ObjectId("5e74ee4fbbc41e36cc3cae6c"), "Name" : "Robert", "Age" : 23 }
{ "_id" : ObjectId("5e74ee56bbc41e36cc3cae6d"), "Name" : "David", "Age" : 23 }
{ "_id" : ObjectId("5e74ee57bbc41e36cc3cae6e"), "Name" : "Robert", "Age" : 23 }
{ "_id" : ObjectId("5e74ee5cbbc41e36cc3cae6f"), "Name" : "Robert", "Age" : 23 }