---
title: Migrating from Bun
description: How to migrate existing bun ORM projects to Grove with zero downtime.
---

Grove is designed for seamless migration from [bun](https://bun.uptrace.dev/). Existing bun models work with Grove unchanged thanks to the dual tag system.

## Step 1: Add Grove Dependency

```bash
go get github.com/xraph/grove
```

## Step 2: Swap the Import

Replace `bun.BaseModel` with `grove.BaseModel`:

```go
// Before
import "github.com/uptrace/bun"

type User struct {
    bun.BaseModel `bun:"table:users,alias:u"`
    ID   int64  `bun:"id,pk,autoincrement"`
    Name string `bun:"name,notnull"`
}

// After — bun tags still work!
import "github.com/xraph/grove"

type User struct {
    grove.BaseModel `bun:"table:users,alias:u"`
    ID   int64  `bun:"id,pk,autoincrement"`
    Name string `bun:"name,notnull"`
}
```

## Step 3: Replace the DB Connection

```go
// Before (bun)
sqldb, _ := sql.Open("pgx", dsn)
db := bun.NewDB(sqldb, pgdialect.New())

// After (grove)
pgdb := pgdriver.New()
pgdb.Open(ctx, dsn, driver.WithPoolSize(20))
db, _ := grove.Open(pgdb)
```

## Step 4: Update Query Syntax

Most bun query patterns have direct Grove equivalents:

| Bun | Grove |
|-----|-------|
| `db.NewSelect(&users).Where("? = ?", bun.Ident("active"), true)` | `db.NewSelect(&users).Where("active = $1", true)` |
| `db.NewInsert(&user).Exec(ctx)` | `db.NewInsert(&user).Exec(ctx)` |
| `db.NewUpdate(&user).WherePK().Exec(ctx)` | `db.NewUpdate(&user).WherePK().Exec(ctx)` |
| `db.NewDelete(&user).WherePK().Exec(ctx)` | `db.NewDelete(&user).WherePK().Exec(ctx)` |

Key difference: Grove uses native PostgreSQL `$1` placeholders instead of bun's `?` with `bun.Ident()`.

## Step 5: Incrementally Adopt Grove Tags

Once your project works with Grove, you can gradually migrate tags to access extended features:

```go
type User struct {
    grove.BaseModel `grove:"table:users,alias:u"`          // Migrated

    ID    int64  `grove:"id,pk,autoincrement"`              // Migrated
    Name  string `bun:"name,notnull"`                       // Still bun — works fine
    Email string `grove:"email,notnull,unique"`              // Migrated
    SSN   string `grove:"ssn,privacy:pii"`                   // New: privacy tag
}
```

## Step 6: Add Grove Features

After migration, take advantage of Grove-specific features:

### Privacy Hooks

```go
db.Hooks().AddHook(&hook.TenantIsolation{Column: "tenant_id"})
```

### Modular Migrations

```go
var Migrations = migrate.NewGroup("myapp")
// Register Go-code migrations with dependency ordering
```

### Multi-Driver Support

```go
// Same models work across databases
pgdb := pgdriver.New()
pgdb.Open(ctx, pgDSN, driver.WithPoolSize(20))
pgDB, _ := grove.Open(pgdb)

mydb := mysqldriver.New()
mydb.Open(ctx, myDSN, driver.WithPoolSize(20))
myDB, _ := grove.Open(mydb)
```

## What Changes

| Feature | Bun | Grove |
|---------|-----|-------|
| Placeholders | `?` | Native per driver (`$1`, `?`) |
| Tag namespace | `bun:"..."` | `grove:"..."` (bun fallback) |
| Privacy tags | Not available | `privacy:pii`, `privacy:sensitive` |
| Multi-driver | PostgreSQL-focused | PG, MySQL, SQLite, MongoDB |
| Migrations | SQL files | Go code with dependency ordering |
| Hooks | Query hooks | Privacy hooks with deny/modify/filter |

## What Stays the Same

- Model structure and field definitions
- Relation tags (`has-one`, `has-many`, `belongs-to`, `many-to-many`)
- Query builder patterns (NewSelect, NewInsert, NewUpdate, NewDelete)
- Soft delete behavior
- Transaction API