---
url: "https://vueda.dev/v3/reference/api/py/vueda.workflow.management.commands.makeworkflowmigrations/RecordDelta.md"
title: "RecordDelta"
---

# RecordDelta

## Overview

What differs between two events, and the two events themselves.

A pghistory event model holds the tracked row's own columns and nothing that compares them, so
the comparison lives here. Everything downstream reads ``changes``, ``old_record``, and
``new_record``.

## `__init__` {#--init--}

### Signature {#--init---signature}

`__init__(changes, old_record, new_record)`

#### Parameters {#--init---parameters}

| Name | Type | Required | Default | Description |
| --- | --- | --- | --- | --- |
| <span id="--init---param-changes">changes</span> |  | yes |  |  |
| <span id="--init---param-old_record">old_record</span> |  | yes |  |  |
| <span id="--init---param-new_record">new_record</span> |  | yes |  |  |

### Source {#--init---source}

`server/vueda/workflow/management/commands/makeworkflowmigrations.py:1143`

## `changes` {#changes}

## `new_record` {#new_record}

## `old_record` {#old_record}

## Source

`server/vueda/workflow/management/commands/makeworkflowmigrations.py:1133`