如何从MongoDB文档中获取电子邮件ID并使用print()显示
为此，请使用forEach()和print()来显示电子邮件ID值。让我们创建一个包含文档的集合-
> db.demo690.insertOne({"UserName":"John","UserEmailId":"John@gmail.com"});
{
"acknowledged" : true,
"insertedId" : ObjectId("5ea6db31551299a9f98c939c")
}
> db.demo690.insertOne({"UserName":"Bob","UserEmailId":"Bob@gmail.com"});
{
"acknowledged" : true,
"insertedId" : ObjectId("5ea6db3c551299a9f98c939d")
}
> db.demo690.insertOne({"UserName":"David","UserEmailId":"David@gmail.com"});
{
"acknowledged" : true,
"insertedId" : ObjectId("5ea6db47551299a9f98c939e")
}在find()方法的帮助下显示集合中的所有文档-
> db.demo690.find();
这将产生以下输出-
{ "_id" : ObjectId("5ea6db31551299a9f98c939c"), "UserName" : "John", "UserEmailId" : "John@gmail.com" }
{ "_id" : ObjectId("5ea6db3c551299a9f98c939d"), "UserName" : "Bob", "UserEmailId" : "Bob@gmail.com" }
{ "_id" : ObjectId("5ea6db47551299a9f98c939e"), "UserName" : "David", "UserEmailId" : "David@gmail.com" }以下是从MongoDB文档获取电子邮件ID并使用以下命令进行打印的查询print()-
> db.demo690.find().forEach(function(document) {
... print(document.UserEmailId);
... });这将产生以下输出-
John@gmail.com Bob@gmail.com David@gmail.com