Add Oracle → PostgreSQL DWH migration tool with daily GitHub Actions schedule

[Copilot]

Implements a Python-based ETL tool to migrate tables from an Oracle DWH to PostgreSQL, schedulable daily via GitHub Actions.

Core modules

• migrate.py – entry point; streams rows from Oracle in configurable batches using oracledb, bulk-inserts into PostgreSQL via psycopg2.extras.execute_values; supports full (truncate+reload) and incremental (append) modes plus --dry-run
• type_mapping.py – Oracle → PostgreSQL type conversion; NUMBER(p,0) maps to SMALLINT/INTEGER/BIGINT/NUMERIC by precision; falls back to TEXT for unknown types
• config.py – all connection params and tuning knobs (PG_SCHEMA, MIGRATION_MODE, MIGRATION_BATCH_SIZE, …) via env vars; no credentials in source

GitHub Actions

• daily_migration.yml – cron 0 2 * * *; workflow_dispatch lets operators override table list, mode, and dry-run at trigger time; uses a production environment for secrets gating
• ci.yml – runs pytest tests/ on every push/PR

Usage

# Migrate all tables (full reload)
python migrate.py

# Targeted incremental run
python migrate.py --tables ORDERS,CUSTOMERS --mode incremental

# Validate connectivity without writing data
python migrate.py --dry-run

Notable design choices

• Oracle SELECT and PostgreSQL INSERT columns are double-quoted to handle reserved words and mixed-case identifiers
• PG_SCHEMA is decoupled from PG_USER; defaults to public
• Both workflow jobs set permissions: contents: read (least privilege)

Original prompt

Questo progetto serve a creare uno strumento di migrazione da DWH in Oracle a uno in Postgres. Vorremmo utilizzare uno script python per effettuare la migrazione e possibilmente schedulandola quotidianamente tramite github actions