在MongoDB上搜索子字段？
要在MongoDB中搜索子字段，可以将双引号和点符号一起使用。首先让我们创建一个包含文档的集合-
> db.searchSubFieldDemo.insertOne(
... {
... "UserDetails":
... {"UserEmailId":"John123@gmail.com","UserAge":21}
... }
... );
{
"acknowledged" : true,
"insertedId" : ObjectId("5cd3d909edc6604c74817ce2")
}
> db.searchSubFieldDemo.insertOne( { "UserDetails": {"UserEmailId":"Carol@yahoo.com","UserAge":26} } );
{
"acknowledged" : true,
"insertedId" : ObjectId("5cd3d9a4edc6604c74817ce3")
}以下是在find()方法的帮助下显示集合中所有文档的查询-
> db.searchSubFieldDemo.find().pretty();
这将产生以下输出-
{
"_id" : ObjectId("5cd3d909edc6604c74817ce2"),
"UserDetails" : {
"UserEmailId" : "John123@gmail.com",
"UserAge" : 21
}
}
{
"_id" : ObjectId("5cd3d9a4edc6604c74817ce3"),
"UserDetails" : {
"UserEmailId" : "Carol@yahoo.com",
"UserAge" : 26
}
}以下是在MongoDB上搜索子字段的查询-
> db.searchSubFieldDemo.find({"UserDetails.UserEmailId":"Carol@yahoo.com"});这将产生以下输出-
{ "_id" : ObjectId("5cd3d9a4edc6604c74817ce3"), "UserDetails" : { "UserEmailId" : "Carol@yahoo.com", "UserAge" : 26 } }