Database Migration Fails During Deployment

1. Migration depends on column that doesn't exist yet
2. Adding NOT NULL column to table with existing rows
3. Foreign key constraint violation from old data
4. Migration file has syntax errors
5. Migrations applied in wrong order due to filename issues

When adding NOT NULL column to existing data, use safe migration pattern:

-- Step 1: Add column with default
ALTER TABLE users ADD COLUMN role TEXT DEFAULT 'user';

-- Step 2: Update existing rows
UPDATE users SET role = 'user' WHERE role IS NULL;

-- Step 3: Add NOT NULL constraint
ALTER TABLE users ALTER COLUMN role SET NOT NULL;

Use Supabase Migrations dashboard to review and rollback if needed.