MongoDB查询以获取嵌套字符串数组？
要在MongoDB中获取嵌套字符串数组，请在中使用点符号find()。让我们创建一个包含文档的集合-
> db.demo89.insertOne(
... { id: 101, Details: [ { Name: "Chris", Marks: 45 }, { Name: "David", Marks: 55, Subjects : ["MySQL", "MongoDB", "Java", "C"] } ]
... }
... );
{
"acknowledged" : true,
"insertedId" : ObjectId("5e2c163b79799acab037af51")
}
> db.demo89.insertOne(
... { id: 102, Details: [ { Name: "Mike", Marks: 48 }, { Name: "Bob", Marks: 98, Subjects : ["C++", "MySQL"] } ]
... }
... );
{
"acknowledged" : true,
"insertedId" : ObjectId("5e2c163c79799acab037af52")
}在find()方法的帮助下显示集合中的所有文档-
> db.demo89.find();
这将产生以下输出-
{ "_id" : ObjectId("5e2c163b79799acab037af51"), "id" : 101, "Details" : [ { "Name" : "Chris", "Marks" : 45 }, { "Name" : "David", "Marks" : 55, "Subjects" : [ "MySQL", "MongoDB", "Java", "C" ] } ] }
{ "_id" : ObjectId("5e2c163c79799acab037af52"), "id" : 102, "Details" : [ { "Name" : "Mike", "Marks" : 48 }, { "Name" : "Bob", "Marks" : 98, "Subjects" : [ "C++", "MySQL" ] } ] }以下是获取嵌套字符串数组的查询-
> db.demo89.find({ "Details.Subjects": "MongoDB"});这将产生以下输出-
{ "_id" : ObjectId("5e2c163b79799acab037af51"), "id" : 101, "Details" : [ { "Name" : "Chris", "Marks" : 45 }, { "Name" : "David", "Marks" : 55, "Subjects" : [ "MySQL", "MongoDB", "Java", "C" ] } ] }