从MongoDB对象获取属性列表？
要从MongoDB对象获取属性列表，可以使用for循环来提取文档的键和值。让我们创建一个包含文档的集合-
>db.getAttributeListDemo.insertOne({"StudentId":101,"StudentName":"John","StudentAdmissi
onDate":new ISODate('2019-01-12'),"StudentSUbjects":["MongoDB","Java","MySQL"]});
{
"acknowledged" : true,
"insertedId" : ObjectId("5cbdfcc9ac184d684e3fa269")
}在find()方法的帮助下显示集合中的所有文档-
> db.getAttributeListDemo.find().pretty();
这将产生以下输出-
{
"_id" : ObjectId("5cbdfcc9ac184d684e3fa269"),
"StudentId" : 101,
"StudentName" : "John",
"StudentAdmissionDate" : ISODate("2019-01-12T00:00:00Z"),
"StudentSUbjects" : [
"MongoDB",
"Java",
"MySQL"
]
}以下是从MongoDB对象获取属性列表的查询-
> var myDocument = db.getAttributeListDemo.findOne();
> for (myKey in myDocument) {
... var originalValue = myDocument[myKey];
... print(myKey + "(" + typeof(originalValue ) + "): " + originalValue ) };这将产生以下输出-
_id(object): 5cbdfcc9ac184d684e3fa269 StudentId(number): 101 StudentName(string): John StudentAdmissionDate(object): Sat Jan 12 2019 05:30:00 GMT+0530 (India Standard Time) StudentSUbjects(object): MongoDB,Java,MySQL