prisma-migrations

# Prisma Migrations Skill

Patterns for managing database migrations with Prisma.

## Migration Workflow

### Development Flow

```bash
# Create and apply migration
npx prisma migrate dev --name add_user_role

# Create migration without applying (for review)
npx prisma migrate dev --create-only --name add_phone

# Apply pending migrations
npx prisma migrate dev

# Reset database (drops and recreates)
npx prisma migrate reset
```

### Production Flow

```bash
# Apply migrations in production
npx prisma migrate deploy

# Check migration status
npx prisma migrate status

# Resolve migration issues
npx prisma migrate resolve --applied "migration_name"
npx prisma migrate resolve --rolled-back "migration_name"
```

## Schema Changes

### Adding Fields

```prisma
// Before
model User {
  id    String @id @default(uuid())
  email String @unique
}

// After - add optional field
model User {
  id    String  @id @default(uuid())
  email String  @unique
  phone String?  // Nullable, no migration issue
}

// After - add required field with default
model User {
  id     String @id @default(uuid())
  email  String @unique
  status String @default("active")  // Has default
}
```

### Renaming Fields

```prisma
// Step 1: Add new field
model User {
  id       String @id @default(uuid())
  name     String   // Old field
  fullName String?  // New field (nullable initially)
}

// Step 2: Run data migration (in code or SQL)
// UPDATE users SET full_name = name;

// Step 3: Make new field required, drop old
model User {
  id       String @id @default(uuid())
  fullName String  // Now required
}
```

### Changing Field Types

```prisma
// Be careful - may lose data!
// Before
model Product {
  price Int  // Cents
}

// After
model Product {
  price Decimal @db.Decimal(10, 2)  // Dollars
}

// Better: Add migration script to convert
// migration.sql will need manual editing
```

### Adding Relations

```prisma
// Step 1: Add optional relation
model Post {
  id         String @id @default(