SLM Database Migrator

A lightweight, local CPU-optimized Database Schema Migrator and ORM Generator. It allows developers to diff SQL schemas, generate database migrations, produce SQLAlchemy/SQLModel classes, and verify safety inside an isolated SQLite memory sandbox.

Features

• Schema Diffing & Migration SQL: Generates exact DDL migration queries (e.g. ALTER TABLE, CREATE INDEX) to reconcile schemas.
• ORM Declarative Mapping: Auto-generates SQLAlchemy/SQLModel classes representing the target database schema.
• SQLite Sandbox Verification: Runs generated DDL statements inside an in-memory sandboxed database connection to catch syntax errors or constraint violations before applying.
• 100% Offline & Local: Relies on local structural matching and offline verification loops.

Installation

pip install -e ./slm_db_migration

API Reference

SLMDBMigrator

from slm_db_migration import SLMDBMigrator

migrator = SLMDBMigrator()

generate_migration(from_schema_sql: str, to_schema_sql: str) -> dict

Generates migration SQL, SQLAlchemy classes, and validates execution inside a sandbox database.

• Arguments:
  • from_schema_sql (str): DDL for the source schema.
  • to_schema_sql (str): DDL for the target schema.
• Returns:
  • dict:

    {
        "success": True/False,
        "migration_sql": str,      # Generated DDL Migration statements
        "sqlalchemy_code": str,     # SQLAlchemy model classes
        "sandbox_result": str       # Status message from SQLite sandbox verification
    }
    

Usage Example

from slm_db_migration import SLMDBMigrator

migrator = SLMDBMigrator()

source_ddl = "CREATE TABLE users (id INT PRIMARY KEY, name TEXT);"
target_ddl = "CREATE TABLE users (id INT PRIMARY KEY, name TEXT, email TEXT);"

result = migrator.generate_migration(source_ddl, target_ddl)

print(f"Success: {result['success']}")
print(f"Migration DDL:\n{result['migration_sql']}")
print(f"SQLAlchemy Models:\n{result['sqlalchemy_code']}")
print(f"Sandbox Verification: {result['sandbox_result']}")

Input & Output Example

Input (Source Schema):

CREATE TABLE users (id INT PRIMARY KEY, name TEXT);

Input (Target Schema):

CREATE TABLE users (id INT PRIMARY KEY, name TEXT, email TEXT);

Output:

{
  "success": true,
  "migration_sql": "ALTER TABLE users ADD COLUMN email TEXT;",
  "sqlalchemy_code": "from sqlalchemy import Column, Integer, String\nfrom sqlalchemy.orm import declarative_base\n...\nclass User(Base):\n    __tablename__ = 'users'\n    id = Column(Integer, primary_key=True)\n    name = Column(String)\n    email = Column(String)",
  "sandbox_result": "Migration verified successfully in SQLite sandbox."
}