MongoDB查询以从文档中删除子文档？
要从文档中删除子文档，请使用$pull和update()。首先让我们创建一个包含文档的集合-
> db.demo538.insertOne(
... {
... id:101,
... "details":
... {
... anotherDetails:
... [
... {
... "Name":"Chris",
... Age:21
... },
... {
... "Name":"David",
... Age:23
... },
... {
... "Name":"Bob",
... Age:20
... }
... ]
... }
... }
... );
{
"acknowledged" : true,
"insertedId" : ObjectId("5e8c8f0aef4dcbee04fbbc08")
}在find()方法的帮助下显示集合中的所有文档-
> db.demo538.find();
这将产生以下输出-
{ "_id" : ObjectId("5e8c8f0aef4dcbee04fbbc08"), "id" : 101, "details" : { "anotherDetails" : [
{ "Name" : "Chris", "Age" : 21 }, { "Name" : "David", "Age" : 23 }, { "Name" : "Bob", "Age" : 20 } ]
} }以下是从文档中删除子文档的查询-
> db.demo538.update({ id:101},
... {$pull : { "details.anotherDetails" : {"Age":23} } } )
WriteResult({ "nMatched" : 1, "nUpserted" : 0, "nModified" : 1 })在find()方法的帮助下显示集合中的所有文档-
> db.demo538.find();
这将产生以下输出-
{ "_id" : ObjectId("5e8c8f0aef4dcbee04fbbc08"), "id" : 101, "details" : { "anotherDetails" : [ {
"Name" : "Chris", "Age" : 21 }, { "Name" : "Bob", "Age" : 20 } ] } }