How can MongoDB ObjectIds be used to find documents based on their creation date?

Finding Documents by Creation Date Using MongoDB ObjectIds

MongoDB ObjectIds hold the timestamp of the document creation within its 12-byte representation. To aid in querying documents based on their creation date, this feature can be leveraged.

Consider the following scenario: you wish to find all documents created after midnight on May 25th, 1980. To accomplish this, you can employ the following approach:

JavaScript Code for Generating Time-Embedded ObjectIds:

<code class="javascript">/* Function creates an ObjectId embedded with a given datetime (Date object or string) */
function objectIdWithTimestamp(timestamp) {
    timestamp = typeof timestamp == 'string' ? new Date(timestamp) : timestamp;
    var hexSeconds = Math.floor(timestamp / 1000).toString(16);
    return ObjectId(hexSeconds + "0000000000000000");
}</code>

Query Example:

<code class="javascript">/* Find documents created after midnight on May 25th, 1980 using the generated ObjectId */
db.mycollection.find({
    _id: {
        $gt: objectIdWithTimestamp('1980/05/25')
    }
});</code>

This query will return all documents with an ObjectId that represents a time greater than the given timestamp. By this means, you can efficiently isolate documents based on their creation date.

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