Implement Change Detection and Version Control

[Oddonline]

Change Detection Implementation

Overview

Need to implement a robust change detection system that can identify differences between XML data sets and generate differential updates.

Requirements

Version Control

• Implement SQLite database for version tracking
• Store hashes of processed entities
• Track changes at entity level
• Maintain change history

Change Detection

• Compare XML files with previous versions
• Identify added/modified/deleted entities
• Generate differential data sets
• Handle schema variations

Data Storage

• Archive previous versions
• Store differential updates
• Maintain data integrity
• Implement cleanup policies

Technical Details

Database Schema

CREATE TABLE entity_versions (
    id INTEGER PRIMARY KEY,
    entity_type TEXT,
    entity_id TEXT,
    hash TEXT,
    version TEXT,
    last_modified DATETIME,
    is_active BOOLEAN
);

CREATE TABLE change_history (
    id INTEGER PRIMARY KEY,
    entity_type TEXT,
    entity_id TEXT,
    change_type TEXT,
    old_hash TEXT,
    new_hash TEXT,
    changed_at DATETIME
);

Change Types

• Added
• Modified
• Deleted
• No Change

Notes

• Must handle large XML files efficiently
• Need to consider memory usage
• Should support rollback capabilities
• Must maintain data consistency