Automating SQL Migrations with Excel-Driven Engines in Spring Boot

The Problem

When a billing platform deprecates objects across hundreds of queries, manual migration is a nightmare. On the Zuora Order Upgrade project, I needed to migrate deprecated object references to new API equivalents — automatically.

The Solution: Excel as a Migration Config

Instead of hardcoding mappings, I used an Excel file as the config layer. Non-technical stakeholders could update the mapping sheet, and the engine would re-generate all SQL.

How It Works

Excel Sheet (mapping config)
      ↓
Apache POI (parse mappings)
      ↓
Migration Engine (Java 21, Spring Boot WebFlux)
      ↓
Auto-generated SQL with JOINs + aliases
      ↓
Validated against Zuora tenant

Key Engineering Decisions

Multi-target Table Mapping

A single deprecated object could map to multiple new tables. The engine resolves this by generating the appropriate JOIN chains automatically.

Automatic JOIN Generation

// Pseudocode: auto JOIN resolution
if (mappingHasMultipleTargets(field)) {
    query.addJoin(resolveJoinPath(sourceTable, targetTables));
}

Alias Handling & Foreign Key Protection

The engine detects aliases in existing queries and preserves them. Foreign key constraints are checked before any transformation is applied.

Results

Migrated hundreds of deprecated Zuora queries automatically
Reduced manual migration effort by 70%+
Caught and fixed critical bugs: pagination failures, notification duplication

Tech Stack

Java 21 · Spring Boot WebFlux · Apache POI · Next.js · PostgreSQL · Docker

Takeaway

Excel-driven config engines are underrated for enterprise automation. They give non-developers control without exposing code — and they scale surprisingly well when backed by a robust Java engine.