leo-claude-mktplace/plugins/saas-db-migrate/commands/db-migrate-generate.md

name, description, agent

name	description	agent
db-migrate generate	Generate migration from model diff	migration-planner

/db-migrate generate - Migration Generator

Skills to Load

• skills/orm-detection.md
• skills/naming-conventions.md
• skills/visual-header.md

Visual Output

Display header: DB-MIGRATE - Generate

Usage

/db-migrate generate <description> [--auto] [--empty]

Arguments:

• <description>: Short description of the change (e.g., "add_orders_table", "add_email_to_users")
• --auto: Auto-detect changes from model diff (Alembic/Prisma only)
• --empty: Generate empty migration file for manual editing

Prerequisites

Run /db-migrate setup first. Reads .db-migrate.json for tool and configuration.

Process

1. Read Configuration

Load .db-migrate.json to determine:

• Migration tool (Alembic, Prisma, raw SQL)
• Migration directory path
• Model directory path (for auto-detection)
• Naming convention

2. Detect Schema Changes (--auto mode)

Alembic:

• Compare current SQLAlchemy models against database schema
• Identify new tables, dropped tables, added/removed columns, type changes
• Detect index additions/removals, constraint changes
• Generate upgrade() and downgrade() functions

Prisma:

• Run prisma migrate diff to compare schema.prisma against database
• Identify model additions, field changes, relation updates
• Generate migration SQL and Prisma migration directory

Raw SQL:

• Auto-detection not available; create empty template
• Include commented sections for UP and DOWN operations

3. Generate Migration File

Create migration file following the naming convention:

Tool	Format	Example
Alembic	{revision}_{description}.py	a1b2c3d4_add_orders_table.py
Prisma	{timestamp}_{description}/migration.sql	20240115120000_add_orders_table/migration.sql
Raw SQL	{sequence}_{description}.sql	003_add_orders_table.sql

4. Include Safety Checks

Every generated migration includes:

• Transaction wrapping (BEGIN/COMMIT or framework equivalent)
• Data preservation warnings for destructive operations
• Rollback function/section (downgrade in Alembic, DOWN in raw SQL)
• Comments explaining each operation

5. Validate Generated Migration

Run safety checks from skills/migration-safety.md on the generated file before presenting to user.

Output Format

+----------------------------------------------------------------------+
|  DB-MIGRATE - Generate                                               |
+----------------------------------------------------------------------+

Tool: Alembic
Mode: auto-detect
Description: add_orders_table

Changes Detected:
  [+] Table: orders (5 columns)
  [+] Column: orders.user_id (FK -> users.id)
  [+] Index: ix_orders_user_id

Files Created:
  [+] alembic/versions/a1b2c3d4_add_orders_table.py

Migration Preview:
  upgrade():
    - CREATE TABLE orders (id, user_id, total, status, created_at)
    - CREATE INDEX ix_orders_user_id ON orders(user_id)
    - ADD FOREIGN KEY orders.user_id -> users.id

  downgrade():
    - DROP INDEX ix_orders_user_id
    - DROP TABLE orders

Safety Check: PASS (no destructive operations)

Next Steps:
  - Review generated migration file
  - Run /db-migrate validate for safety analysis
  - Run /db-migrate plan to see execution plan

Important Notes

• Auto-detection works best with Alembic and Prisma
• Always review generated migrations before applying
• Destructive operations (DROP, ALTER TYPE) are flagged with warnings
• The --empty flag is useful for data migrations that cannot be auto-detected