MongoDB中的deleteOne()和findOneAndDelete()操作之间有什么区别？
deleteOne()从集合中删除单个文档。
让我们看一个示例并创建包含文档的集合-
> db.demo448.insertOne({"Name":"Chris","Age":21});{
"acknowledged" : true,
"insertedId" : ObjectId("5e7a291cbbc41e36cc3caeca")
}
> db.demo448.insertOne({"Name":"David","Age":23});{
"acknowledged" : true,
"insertedId" : ObjectId("5e7a2926bbc41e36cc3caecb")
}
> db.demo448.insertOne({"Name":"Bob","Age":22});{
"acknowledged" : true,
"insertedId" : ObjectId("5e7a2930bbc41e36cc3caecc")
}在find()方法的帮助下显示集合中的所有文档-
> db.demo448.find();
这将产生以下输出-
{ "_id" : ObjectId("5e7a291cbbc41e36cc3caeca"), "Name" : "Chris", "Age" : 21 }
{ "_id" : ObjectId("5e7a2926bbc41e36cc3caecb"), "Name" : "David", "Age" : 23 }
{ "_id" : ObjectId("5e7a2930bbc41e36cc3caecc"), "Name" : "Bob", "Age" : 22 }以下是实现deleteOne()的查询-
> db.demo448.deleteOne({_id:ObjectId("5e7a2926bbc41e36cc3caecb")});这将产生以下输出-
{ "acknowledged" : true, "deletedCount" : 1 }在find()方法的帮助下显示集合中的所有文档-
> db.demo448.find();
这将产生以下输出-
{ "_id" : ObjectId("5e7a291cbbc41e36cc3caeca"), "Name" : "Chris", "Age" : 21 }
{ "_id" : ObjectId("5e7a2930bbc41e36cc3caecc"), "Name" : "Bob", "Age" : 22 }以下是实现findOneAndDelete()的查询-
> db.demo448.findOneAndDelete({"_id":ObjectId("5e7a2930bbc41e36cc3caecc")});这将产生以下输出-
{ "_id" : ObjectId("5e7a2930bbc41e36cc3caecc"), "Name" : "Bob", "Age" : 22 }在find()方法的帮助下显示集合中的所有文档-
> db.demo448.find();
这将产生以下输出-
{ "_id" : ObjectId("5e7a291cbbc41e36cc3caeca"), "Name" : "Chris", "Age" : 21 }