How Time Is Represented in a Source
Explore the ways that Visier defines time for records uploaded to our platform.
The following table defines key terms related to time in data uploads.
| Term | Definition |
|---|---|
| Timestamp | A time value added by a program or system to a file, message, or record indicating the time and date when the file, message, or record was created or last modified. |
| Time shifting | Modifying a timestamp via edit, script, or calculation. |
| Upload time | A timestamp for when a record was uploaded to the platform. |
| Snapshot time | A timestamp representing when a record was true in the source system. |
Snapshot time
The snapshot time represents when a record was true in the source system. This is often when the record was exported from the source system, such as an HRIS.
If the records are part of a file, then the file's properties record the snapshot time. When a user uploads the record to Visier, the platform overwrites the existing snapshot time with the upload time.
Example:
Let's say you exported a set of records from your HRIS on 2020 August 1 at 09:00:13.214Z. The time of the export is the snapshot time. If you upload these records to Visier on 2020 August 5 at 3:00PM, that is the upload time (UTC). Because the UTC overwrites the original snapshot time, there is a time difference of about four days and six hours later. As a result, you may want to adjust the snapshot time by minus 102 hours to represent the original snapshot time.
Visier's snapshot time adjustment
You may want to change the snapshot time to correct previously uploaded records. For example, if you uploaded a file three months ago and want to replace a record in that file by uploading a new file today, you can change the snapshot time of today's file to three months ago.
The loader can calculate the snapshot time from the upload time using the offset and snap to midnight settings. These settings can be enabled individually or simultaneously.
The offset value is an integer number of hours in the following equation:
Snapshot time = Upload time + Offset
Snap to midnight is a Boolean and, when enabled, the time of the snapshot time is zeroed. For example, 20200801 09:00:13.214Z becomes 20200801 00:00:00.000Z.