在MongoDB中使用$ push更新数组
updateOne()在MongoDB中使用。让我们创建一个包含文档的集合-> db.demo526.insertOne(
... {
...
... "CountryName": "US",
... "TeacherName": "Bob",
... "StudentInformation": [
... {
... "Name": "Chris",
... "Subject": "MySQL",
... "ListOfMailId":[]
... },
... {
... "Name": "David",
... "Subject": "MongoDB",
... "ListOfMailId":[]
...
... }
... ]
... }
... );
{
"acknowledged" : true,
"insertedId" : ObjectId("5e8af031437efc8605595b6b")
}在find()方法的帮助下显示集合中的所有文档-
> db.demo526.find();
这将产生以下输出-
{ "_id" : ObjectId("5e8af031437efc8605595b6b"), "CountryName" : "US", "TeacherName" :
"Bob", "StudentInformation" : [ { "Name" : "Chris", "Subject" : "MySQL", "ListOfMailId" : [ ] }, {
"Name" : "David", "Subject" : "MongoDB", "ListOfMailId" : [ ] } ] }以下是使用$push更新数组的查询-
> db.demo526.updateOne(
... {
... _id:ObjectId("5e8af031437efc8605595b6b"),
... "StudentInformation": { "$elemMatch": { "Name": "David", "Subject": "MongoDB" }}
... },
... {
... "$push": { "StudentInformation.$.ListOfMailId": { "MailId": "David@gmail.com" }}
...
... }
... )
{ "acknowledged" : true, "matchedCount" : 1, "modifiedCount" : 1 }在find()方法的帮助下显示集合中的所有文档-
> db.demo526.find();
这将产生以下输出-
{ "_id" : ObjectId("5e8af031437efc8605595b6b"), "CountryName" : "US", "TeacherName" : "Bob", "StudentInformation" : [
{ "Name" : "Chris", "Subject" : "MySQL", "ListOfMailId" : [ ] },
{ "Name" : "David", "Subject" : "MongoDB", "ListOfMailId" : [ { "MailId" : "David@gmail.com" } ] }
] }