Migration Patterns Skill

TEMPLATE: This skill uses {{PLACEHOLDER}} tokens. Replace with your project values before use.

Purpose

Guide database migration creation with mandatory RLS policies, following security-first architecture and approval workflow.

When This Skill Applies

Creating database migrations
Adding new tables (all tables need RLS)
Updating ORM schema
Adding GRANT statements
Schema impact analysis
Data migration planning

Stop-the-Line Conditions

FORBIDDEN Patterns

-- FORBIDDEN: RLS policies in separate file
-- RLS MUST be in the same migration file as the table creation

-- FORBIDDEN: Table without RLS
CREATE TABLE user_data (...);
-- Missing: ALTER TABLE user_data ENABLE ROW LEVEL SECURITY;

-- FORBIDDEN: Resolve applied migrations (bypasses verification)
-- npx prisma migrate resolve --applied "migration_name"
-- alembic stamp head

-- FORBIDDEN: Missing user_id index
CREATE TABLE payments (...);
-- Missing: CREATE INDEX idx_payments_user_id ON payments(user_id);

-- FORBIDDEN: Schema changes without ARCHitect approval
-- All migrations require approval before PR

CORRECT Patterns

-- CORRECT: Complete migration with RLS in same file
CREATE TABLE user_data (
  id UUID PRIMARY KEY DEFAULT gen_random_uuid(),
  user_id TEXT NOT NULL,
  data JSONB,
  created_at TIMESTAMPTZ DEFAULT NOW()
);

-- Enable RLS (SAME FILE - MANDATORY)
ALTER TABLE user_data ENABLE ROW LEVEL SECURITY;

-- User policy
CREATE POLICY user_data_user_select ON user_data
  FOR SELECT TO {{PROJECT}}_app_user
  USING (user_id = current_setting('app.current_user_id', true));

-- Index for RLS performance (MANDATORY)
CREATE INDEX idx_user_data_user_id ON user_data(user_id);

-- Grant permissions
GRANT SELECT, INSERT, UPDATE ON user_data TO {{PROJECT}}_app_user;

Migration Workflow (MANDATORY)

Step 1: Get ARCHitect Approval

Before ANY schema change:

1. Document proposed changes
2. Get ARCHitect approval (create issue or discussion)
3. Only proceed after explicit approval

Step 2: Create Migration

# For Prisma
npx prisma migrate dev --name descriptive_name

# For Alembic
alembic revision --autogenerate -m "descriptive_name"

# Verify migration file created
ls {{MIGRATIONS_DIR}}/

Step 3: Add RLS to Migration

Edit the generated migration to include:

ALTER TABLE ... ENABLE ROW LEVEL SECURITY
User SELECT policy
User INSERT policy (if applicable)
User UPDATE policy (if applicable)
Admin policies (if needed)
System policies (for background jobs)
Index on user_id column
GRANT statements

Step 4: Verify Locally

# Test migration
{{MIGRATION_RUN_COMMAND}}

# Verify RLS is enabled
psql -c "SELECT tablename, rowsecurity FROM pg_tables WHERE schemaname = 'public';"

Step 5: Update Documentation

After successful migration:

Update docs/database/DATA_DICTIONARY.md (MANDATORY)
Update RLS policy catalog if new policies added
Document in ticket

RLS Policy Templates

User Read Policy

CREATE POLICY {table}_user_select ON {table}
  FOR SELECT TO {{PROJECT}}_app_user
  USING (user_id = current_setting('app.current_user_id', true));

User Write Policy

CREATE POLICY {table}_user_insert ON {table}
  FOR INSERT TO {{PROJECT}}_app_user
  WITH CHECK (user_id = current_setting('app.current_user_id', true));

Admin Policy

CREATE POLICY {table}_admin_all ON {table}
  FOR ALL TO {{PROJECT}}_app_user
  USING (current_setting('app.user_role', true) = 'admin');

System Policy (Background Jobs)

CREATE POLICY {table}_system_all ON {table}
  FOR ALL TO {{PROJECT}}_app_user
  USING (current_setting('app.context_type', true) = 'system');

Migration Checklist

Before PR:

Production Migration Requirements

For production migrations:

POPM/lead must be present (MANDATORY)
Backup taken before migration
Rollback plan documented
Post-migration validation steps defined
Data integrity checks planned

Authoritative References

Migration SOP: docs/database/RLS_DATABASE_MIGRATION_SOP.md (MANDATORY)
Data Dictionary: docs/database/DATA_DICTIONARY.md (update after changes)
RLS Implementation: docs/database/RLS_IMPLEMENTATION_GUIDE.md
RLS Policies: docs/database/RLS_POLICY_CATALOG.md
Security First: docs/guides/SECURITY_FIRST_ARCHITECTURE.md

migration-patterns