---

name: db-migrate description: Generate GORM database migration code. Use when modifying database schema. argument-hint: [migration-description]

DB Migration Generator

Generate migration for: $ARGUMENTS

Instructions

1. Review current schema in docs/REQUIREMENTS.md section 8
2. Generate GORM AutoMigrate compatible model changes
3. Handle both up and down migrations

GORM Model Convention

package persistence

import (
    "time"
    "github.com/google/uuid"
    "gorm.io/gorm"
)

// Infrastructure model (NOT domain entity)
type BookModel struct {
    ID         uuid.UUID  `gorm:"type:uuid;primary_key;default:gen_random_uuid()"`
    UserID     uuid.UUID  `gorm:"type:uuid;not null;index"`
    Title      string     `gorm:"type:varchar(255);not null"`
    Author     string     `gorm:"type:varchar(255);not null"`
    Status     string     `gorm:"type:varchar(50);not null;default:'unread'"`
    FinishedAt *time.Time `gorm:"type:timestamp"`
    CreatedAt  time.Time  `gorm:"autoCreateTime"`
    UpdatedAt  time.Time  `gorm:"autoUpdateTime"`
}

func (BookModel) TableName() string {
    return "books"
}

Rules

• Infrastructure models are SEPARATE from domain entities
• Include proper indexes for query performance
• Use UUID for all primary keys
• Use JSONB for flexible fields (pokemon_types)
• Add foreign key constraints
• Consider lock order when adding new tables