What is the best way to retrieve random records from MongoDB?
I have come across various articles on StackOverflow discussing this topic, but I am struggling to grasp the concept. For instance:
db.yourCollection.find().limit(-1).skip(yourRandomNumber).next()
How can I implement this code in my own project? (assuming the collection is named User)
User.findOne(RANDOM PLAYER).then(result) {
console.log(result);
}
To select a random record from a set of matching records, we can utilize the findOne() method without specifying any criteria.
The next step is to randomly choose one entry from all the possible matches by following these steps:
Determine the total number of potential entries by using the count() function on the collection. It's worth noting that in version 4, the use of count is considered deprecated, and alternatives like estimatedDocumentCount or countDocuments are recommended for better precision and memory management. This Stack Overflow thread provides further insights into this topic.
Generate a random number within the count obtained.
Utilize the skip() method to move to the desired match position and retrieve that specific record.
Below is an excerpt adapted from this relevant Stack Overflow response:
// Obtain the total user count
User.count().exec(function (err, count) {
// Select a random entry
var random = Math.floor(Math.random() * count)
// Query all users once again, but fetch only the one at the randomized offset
User.findOne().skip(random).exec(
function (err, result) {
// Voilà! A random user is retrieved
console.log(result)
})
})
If you want to retrieve random documents from mongodb using mongoose.
limitrecords=10;
function getRandomArbitrary(min, max) {
return Math.ceil(Math.random() * (max - min) + min);
}
var userschema = new Schema({
name: String
});
User = mongoose.model('User', userschema);
User.count({your_query},function(err,count){
var skipRecords = getRandomArbitrary(1, count-limitrecords);
query.skip(skipRecords); // Random Offset
query.exec(function(err,result){
console.log(result); // 10 random users
});
});
This code snippet demonstrates fetching 10 random records, but you can adjust the "limitrecords" variable based on your needs.
Cheers!
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