How to Get Epoch/UNIX Timestamp in MongoDB

In MongoDB, you can get Epoch timestamps by working with BSON date objects. This article explores different ways to retrieve and use Epoch timestamps in MongoDB and provides practical use cases.

Using BSON Date Objects

In MongoDB, you can work with BSON date objects to represent and manipulate timestamps. BSON date objects provide a rich way to interact with time-related data.

Example Query

To obtain the current Epoch timestamp using BSON date objects, you can use the following MongoDB query:

db.timestamps.insert({ timestamp: new ISODate() });

This query inserts a BSON date object into a collection called "timestamps" with the current timestamp.

Use Case 1: Logging Timestamps

To log data with timestamps, you can utilize BSON date objects in MongoDB. Here's an example query:

db.sensor_data.insert({
    data: "Sensor data reading...",
    timestamp: new ISODate()
});

In this query, sensor data is logged along with the current Epoch timestamp in a collection named "sensor_data."

Use Case 2: Time Duration Calculation

If you need to measure the time taken for a task, you can record start and end times using BSON date objects. Here's how you can calculate the time elapsed in seconds:

db.task_log.insert({
    task_description: "Task started",
    start_time: new ISODate()
});

// Perform a task or operation

var endTime = new ISODate();
db.task_log.update(
    { task_description: "Task started" },
    { $set: { end_time: endTime } }
);

var startTimestamp = db.task_log.findOne({ task_description: "Task started" }).start_time.getTime();
var endTimestamp = endTime.getTime();
var timeElapsedInSeconds = (endTimestamp - startTimestamp) / 1000;
print("Time taken: " + timeElapsedInSeconds + " seconds");

This query records the start time when a task begins and the end time when it ends. It then calculates the time elapsed in seconds using BSON date objects.

Use Case 3: Expiry Timestamp for Cache

If you need to set an expiry timestamp for cache data, you can use BSON date objects in MongoDB. Here's an example query:

var currentTimestamp = new ISODate();
var expiryTimestamp = new ISODate(currentTimestamp.getTime() + 600 * 1000);

db.cached_data.insert({
    data: "Cached data...",
    expiry_timestamp: expiryTimestamp
});

In this query, the current Epoch timestamp is obtained using a BSON date object, and then 600 seconds (10 minutes) are added to it to determine the cache expiry time. The data is inserted into a collection named "cached_data."

Use Case 4: Event Scheduling

To schedule an event to occur in the future, you can use BSON date objects in MongoDB. Here's an example query:

var eventTimestamp = new ISODate();
eventTimestamp.setTime(eventTimestamp.getTime() + 3600 * 1000); // 1 hour from now

while (new ISODate() < eventTimestamp) {
    // Waiting for the event to occur
}

print("Event occurred!");

This query calculates the event time as one hour from the current time using BSON date objects. It then waits for the event to occur using a loop and prints a message when the event occurs.

These code examples illustrate how to get Epoch/UNIX timestamps in MongoDB using BSON date objects and showcase their applications in practical scenarios. Whether you need to log data with timestamps, calculate time durations, set cache expiry times, or schedule events, BSON date objects are versatile tools in MongoDB for time-related operations.