Track Changes in Frappe

Many of you are likely familiar with the 'Track Changes' option in a Frappe DocType. But have you ever pondered over the mechanics behind it? Even if you haven't, understanding how it works can be a valuable asset.

When 'Track Changes' is enabled for a DocType, each time a document of that type undergoes an update, a corresponding record is generated in the 'Version' DocType. This record encapsulates the additions, deletions, and modifications made during that specific save instance. The interesting aspect of a 'Version' document lies in its storage format—it preserves the data as a JSON by comparing the document before and after the update. The JSON structure looks like this:

{

"added": [],       // Contains newly added data

"changed": [],     // Contains modifications with before and after values

"data_import": null,

"removed": [],     // Contains removed data

"row_changed": [], // Contains added, changed, and removed data for child table entries

"updater_reference": null

}

Each element encompasses every metadata detail of the modified data upon the document update. Essentially, Versioning acts as a form of backup, though not as user-friendly for restoration with a single click. Despite this, it stands as a powerful feature in Frappe, serving as a fail-safe in case of issues with database backups. While its primary purpose is to visualize document changes for end users, its backup capabilities add an extra layer of reassurance.