ORMを試してみました

2022年8月18日 14:04

こんにちは。レスキューナウでシステムエンジニアをしている室伏です。
弊社では、近年バックエンドの開発で、Go言語が採用されて、
今回はGoとDB（MySql）の連携のためのORMについて、試してみました。

ORMとは？

オブジェクト関係マッピング（英: Object-relational mapping、O/RM、ORM）とは、
データベースとオブジェクト指向プログラミング言語の間の非互換なデータを変換するプログラミング技法である。
オブジェクト関連マッピングとも呼ぶ。実際には、オブジェクト指向言語から使える「仮想」オブジェクトデータベースを構築する手法である。
オブジェクト関係マッピングを行うソフトウェアパッケージは商用のものもフリーなものもあるが、場合によっては独自に開発することもある。　　
「オブジェクト関係マッピング」『フリー百科事典ウィキペディア
　　　日本語版』。2021年11月12日 (金) 07:34 UTC、
　　　URL：オブジェクト関係マッピング - Wikipedia

簡単にいうと、SQLを直接書くことなく、オブジェクトのメソッドでDB操作ができる、という感じです。
Goで使用可能なORMはいくつかあるのですが、今回はGORM、XORM、SQL Boilerについて簡単なサンプルを実装してみました。（APIが呼ばれ、Responseを返すサンプルとなります）
※成果物から抜粋したコードなので直接は使用できません。

環境情報

Go 1.17
Mysql 5.6
ORM
- gorm gorm.io/gorm v1.23.8
- xorm xorm.io/xorm v1.3.1
- sqlBoiler github.com/volatiletech/sqlboiler/v4 v4.11.0

テーブル情報

CREATE TABLE `country` (
  `id` bigint(20) NOT NULL AUTO_INCREMENT,
  `name` varchar(1024) DEFAULT NULL,
  `created_at` datetime DEFAULT NULL,
  PRIMARY KEY (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=10 DEFAULT CHARSET=utf8

CREATE TABLE `user` (
  `id` bigint(20) NOT NULL AUTO_INCREMENT,
  `name` varchar(1024) DEFAULT NULL,
  `age` bigint(20) DEFAULT NULL,
  PRIMARY KEY (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=10 DEFAULT CHARSET=utf8

GORM

インストール

go get -u gorm.io/driver/mysql
go get -u gorm.io/gorm

CRUD実装サンプル

type Gorm struct {
	Gorm *gorm.DB
}

type Country struct {
	Id string `sql:"size:1024" json:"id"`
	Name string `sql:"size:1024" json:"name"`
}

type User struct {
	Id     string
	Name   string
	Age    string
}

// 初期化
func (g *Gorm) InitGorm() {

	user := "dbuser"
	pw := "dbpassward"
	db_name := "testdb"
	var path string = fmt.Sprintf("%s:%s@tcp(xx.xx.xx.xx:3306)/%s?charset=utf8&parseTime=true", user, pw, db_name)
	diact := mysql.Open(path)
	var err error
	if g.Db, err = gorm.Open(diact); err != nil {
		log.Fatalf("Got error when connect database, the error is '%v'", err)
	}

	fmt.Println("db connected!!")
}

// 取得（countryテーブルから1件取得）
func (g *Gorm) GetCountry(w rest.ResponseWriter, r *rest.Request) {
	id := r.PathParam("id")
	country := Country{}
	if g.Gorm.Table("country").Find(&country, id).Error != nil {
		rest.NotFound(w, r)
		return
	}
	w.WriteJson(&country)
}

// 取得（countryテーブルから全件取得）
func (g *Gorm) GetAllCountries(w rest.ResponseWriter, r *rest.Request) {
	country := []Country{}
	g.Gorm.Table("country").Find(&country)
	w.WriteJson(country)
}

// 登録
func (g *Gorm) PostCountry(w rest.ResponseWriter, r *rest.Request) {
	country := Country{}
	err := r.DecodeJsonPayload(&country)
	if err != nil {
		rest.Error(w, err.Error(), http.StatusInternalServerError)
	}
	err = g.Gorm.Table("country").Save(&country).Error
	if err != nil {
		rest.Error(w, err.Error(), http.StatusInternalServerError)
		return
	}
	w.WriteJson(&country)
}

// 更新
func (g *Gorm) PutCountry(w rest.ResponseWriter, r *rest.Request) {

	id := r.PathParam("id")
	country := Country{}
	if g.Db.Table("country").First(&country, id).Error != nil {
		rest.NotFound(w, r)
		return
	}
	updated := domain.Country{}
	if err := r.DecodeJsonPayload(&updated); err != nil {
		rest.Error(w, err.Error(), http.StatusInternalServerError)
		return
	}

	country.Name = updated.Name

	if err := g.Gorm.Table("country").Save(&country).Error; err != nil {
		rest.Error(w, err.Error(), http.StatusInternalServerError)
		return
	}
	w.WriteJson(&country)
}

// 削除
func (g *Gorm) DeleteCountry(w rest.ResponseWriter, r *rest.Request) {
	id := r.PathParam("id")
	country := Country{}
	if g.Db.Table("country").First(&country, id).Error != nil {
		rest.NotFound(w, r)
		return
	}
	if err := g.Gorm.Table("country").Delete(&country).Error; err != nil {
		rest.Error(w, err.Error(), http.StatusInsufficientStorage)
		return
	}
	w.WriteHeader(http.StatusOK)
}

// 生SQLの実施
func (g *Gorm) GetCountrySQL(w rest.ResponseWriter, r *rest.Request) {

	result := []User{}
	sql := "SELECT Id, Name, Age FROM User"

	rows, err := g.Db.Raw(sql).Rows()
	defer rows.Close()
	for rows.Next() {
		//result = append(result, i.DB.ScanRows(rows, &User{}))
		s := User{}
		g.Db.ScanRows(rows, &s)
		result = append(result, s)
	}

	if err != nil {
		log.Fatal(err)
	}

	w.WriteJson(result)
}

XORM

インストール

go get xorm.io/xorm

CRUD実装サンプル

type Xorm struct {
	engine *xorm.Engine
}

type Country struct {
	Name string `sql:"size:1024" json:"name"`
}

type User struct {
	Id     string
	Name   string
	Age    string
}

// 初期化
func (x *Xorm) InitDBXorm() {
	var err error
	// MySQLとの接続。
	x.engine, _ = xorm.NewEngine("mysql", "dbuser:dbpassword@tcp(xx.xx.xx.xx:3306)/testdb?charset=utf8mb4&parseTime=true")
	if err != nil {
		log.Fatalf("Got error when connect database, the error is '%v'", err)
	}

	x.engine.ShowSQL(true)
}

// 1件取得
func (x *Xorm) GetAllCountries(w rest.ResponseWriter, r *rest.Request) {
	countries := []Country{}

	err := x.engine.Find(&countries)
	if err != nil {
		log.Fatal(err)
	}

	w.WriteJson(countries)
}

// 全件取得
func (x *Xorm) GetCountry(w rest.ResponseWriter, r *rest.Request) {
	id := r.PathParam("id")
	country := Country{}

	result, err := x.engine.Where("id = ?", id).Get(&country)
	if err != nil {
		log.Fatal(err)
	}
	if !result {
		log.Fatal("Not Found")
	}
	w.WriteJson(&country)
}

// 登録
func (x *Xorm) PostCountry(w rest.ResponseWriter, r *rest.Request) {
	country := Country{}
	err := r.DecodeJsonPayload(&country)

	_, err = x.engine.Insert(country)
	if err != nil {
		rest.Error(w, err.Error(), http.StatusInternalServerError)
	}

	w.WriteJson(&country)
}

// 更新
func (x *Xorm) PutCountry(w rest.ResponseWriter, r *rest.Request) {

	id := r.PathParam("id")

	updated := Country{}
	if err := r.DecodeJsonPayload(&updated); err != nil {
		rest.Error(w, err.Error(), http.StatusInternalServerError)
		return
	}

	result, err := x.engine.Where("id =?", id).Update(&updated)
	if err != nil {
		rest.Error(w, err.Error(), http.StatusInternalServerError)
	}

	w.WriteJson(result)
}

// 削除
func (x *Xorm) DeleteCountry(w rest.ResponseWriter, r *rest.Request) {
	id := r.PathParam("id")

	_, err := x.engine.ID(id).Delete(&Country{})
	if err != nil {
		rest.Error(w, err.Error(), http.StatusInternalServerError)
	}

	w.WriteHeader(http.StatusOK)
}

// 生SQLの実施
func (x *Xorm) GetCountrySQL(w rest.ResponseWriter, r *rest.Request) {

	user := []User{}

	sql := "SELECT Id, Name, Age FROM User" 

	err := x.engine.SQL(sql).Find(&user)
	if err != nil {
		log.Fatal(err)
	}

	w.WriteJson(summary)
}

SQLBoiler

インストール

# slqboilerのインストール
go install github.com/volatiletech/sqlboiler/v4@latest

# driverのインストール(今回はMySQL)
go install github.com/volatiletech/sqlboiler/v4/drivers/sqlboiler-mysql@latest

go get github.com/volatiletech/null/v8

DBから構造体を抽出

# sqlboiler.toml（下記のコマンドを実行する場所に、tomlファイルを用意）
[mysql]
  dbname="testdb"
  host="xx.xx.xx.xx"
  port=3306
  user="dbuser"
  pass="dbpassword"
  sslmode="false"
#  whitelist=["NOTICE","USER_MST","country"]

# コマンド
sqlboiler mysql

CRUD実装サンプル



type User struct {
	Id     string
	Name   string
	Age    string
}

type SqlBoiler struct {
	Handler *sql.DB
}

// 1件取得
func (s *SqlBoiler) GetCountry(w rest.ResponseWriter, r *rest.Request) {
	ctx := context.Background()

	id := r.PathParam("id")
	countries, err := models.Countries(qm.Where("id=?", id)).All(ctx, s.Handler)
	if err != nil {
		rest.Error(w, err.Error(), http.StatusInternalServerError)
	}

	w.WriteJson(&countries)
}

// 全件取得
func (s *SqlBoiler) GetAllCountries(w rest.ResponseWriter, r *rest.Request) {
	ctx := context.Background()

	countries, err := models.Countries().All(ctx, s.Handler)
	if err != nil {
		rest.Error(w, err.Error(), http.StatusInternalServerError)
	}

	w.WriteJson(&countries)
}

// 登録
func (s *SqlBoiler) PostCountry(w rest.ResponseWriter, r *rest.Request) {
	ctx := context.Background()

	country := models.Country{}
	err := r.DecodeJsonPayload(&country)
	if err != nil {
		rest.Error(w, err.Error(), http.StatusInternalServerError)
	}

	err = country.Insert(ctx, s.Handler, boil.Infer())
	if err != nil {
		rest.Error(w, err.Error(), http.StatusInternalServerError)
		return
	}

	w.WriteJson(&country)
}

// 更新
func (s *SqlBoiler) PutCountry(w rest.ResponseWriter, r *rest.Request) {
	ctx := context.Background()

	country := models.Country{}
	err := r.DecodeJsonPayload(&country)
	if err != nil {
		rest.Error(w, err.Error(), http.StatusInternalServerError)
	}

	_, err = country.Update(ctx, s.Handler, boil.Infer())
	if err != nil {
		rest.Error(w, err.Error(), http.StatusInternalServerError)
		return
	}

	w.WriteJson(&country)
}

// 削除
func (s *SqlBoiler) DeleteCountry(w rest.ResponseWriter, r *rest.Request) {
	id := r.PathParam("id")
	ctx := context.Background()

	pid, _ := strconv.ParseInt(id, 10, 64)
	country := models.Country{ID: pid}

	if _, err := country.Delete(ctx, s.Handler); err != nil {
		rest.Error(w, err.Error(), http.StatusInsufficientStorage)
		return
	}
	w.WriteHeader(http.StatusOK)
}

// 生SQLの実施
func (s *SqlBoiler) GetCounttryCond(w rest.ResponseWriter, r *rest.Request) {

	var u []*User

	ctx := context.Background()

	sql := "SELECT Id, Name, Age FROM User

	err := queries.Raw(sql).Bind(ctx, s.Handler, &u)
	if err != nil {
		rest.Error(w, err.Error(), http.StatusInsufficientStorage)
		return
	}

	w.WriteJson(&su)
}

sqlBoilerでDBから生成した構造体

// Code generated by SQLBoiler 4.11.0 (https://github.com/volatiletech/sqlboiler). DO NOT EDIT.
// This file is meant to be re-generated in place and/or deleted at any time.

package models

import (
	"context"
	"database/sql"
	"fmt"
	"reflect"
	"strconv"
	"strings"
	"sync"
	"time"

	"github.com/friendsofgo/errors"
	"github.com/volatiletech/null/v8"
	"github.com/volatiletech/sqlboiler/v4/boil"
	"github.com/volatiletech/sqlboiler/v4/queries"
	"github.com/volatiletech/sqlboiler/v4/queries/qm"
	"github.com/volatiletech/sqlboiler/v4/queries/qmhelper"
	"github.com/volatiletech/strmangle"
)

// Country is an object representing the database table.
type Country struct {
	ID        int64       `boil:"id" json:"id" toml:"id" yaml:"id"`
	Name      null.String `boil:"name" json:"name,omitempty" toml:"name" yaml:"name,omitempty"`
	CreatedAt null.Time   `boil:"created_at" json:"created_at,omitempty" toml:"created_at" yaml:"created_at,omitempty"`

	R *countryR `boil:"-" json:"-" toml:"-" yaml:"-"`
	L countryL  `boil:"-" json:"-" toml:"-" yaml:"-"`
}

var CountryColumns = struct {
	ID        string
	Name      string
	CreatedAt string
}{
	ID:        "id",
	Name:      "name",
	CreatedAt: "created_at",
}

var CountryTableColumns = struct {
	ID        string
	Name      string
	CreatedAt string
}{
	ID:        "country.id",
	Name:      "country.name",
	CreatedAt: "country.created_at",
}

// Generated where

type whereHelperint64 struct{ field string }

func (w whereHelperint64) EQ(x int64) qm.QueryMod  { return qmhelper.Where(w.field, qmhelper.EQ, x) }
func (w whereHelperint64) NEQ(x int64) qm.QueryMod { return qmhelper.Where(w.field, qmhelper.NEQ, x) }
func (w whereHelperint64) LT(x int64) qm.QueryMod  { return qmhelper.Where(w.field, qmhelper.LT, x) }
func (w whereHelperint64) LTE(x int64) qm.QueryMod { return qmhelper.Where(w.field, qmhelper.LTE, x) }
func (w whereHelperint64) GT(x int64) qm.QueryMod  { return qmhelper.Where(w.field, qmhelper.GT, x) }
func (w whereHelperint64) GTE(x int64) qm.QueryMod { return qmhelper.Where(w.field, qmhelper.GTE, x) }
func (w whereHelperint64) IN(slice []int64) qm.QueryMod {
	values := make([]interface{}, 0, len(slice))
	for _, value := range slice {
		values = append(values, value)
	}
	return qm.WhereIn(fmt.Sprintf("%s IN ?", w.field), values...)
}
func (w whereHelperint64) NIN(slice []int64) qm.QueryMod {
	values := make([]interface{}, 0, len(slice))
	for _, value := range slice {
		values = append(values, value)
	}
	return qm.WhereNotIn(fmt.Sprintf("%s NOT IN ?", w.field), values...)
}

var CountryWhere = struct {
	ID        whereHelperint64
	Name      whereHelpernull_String
	CreatedAt whereHelpernull_Time
}{
	ID:        whereHelperint64{field: "`country`.`id`"},
	Name:      whereHelpernull_String{field: "`country`.`name`"},
	CreatedAt: whereHelpernull_Time{field: "`country`.`created_at`"},
}

// CountryRels is where relationship names are stored.
var CountryRels = struct {
}{}

// countryR is where relationships are stored.
type countryR struct {
}

// NewStruct creates a new relationship struct
func (*countryR) NewStruct() *countryR {
	return &countryR{}
}

// countryL is where Load methods for each relationship are stored.
type countryL struct{}

var (
	countryAllColumns            = []string{"id", "name", "created_at"}
	countryColumnsWithoutDefault = []string{"name", "created_at"}
	countryColumnsWithDefault    = []string{"id"}
	countryPrimaryKeyColumns     = []string{"id"}
	countryGeneratedColumns      = []string{}
)

type (
	// CountrySlice is an alias for a slice of pointers to Country.
	// This should almost always be used instead of []Country.
	CountrySlice []*Country
	// CountryHook is the signature for custom Country hook methods
	CountryHook func(context.Context, boil.ContextExecutor, *Country) error

	countryQuery struct {
		*queries.Query
	}
)

// Cache for insert, update and upsert
var (
	countryType                 = reflect.TypeOf(&Country{})
	countryMapping              = queries.MakeStructMapping(countryType)
	countryPrimaryKeyMapping, _ = queries.BindMapping(countryType, countryMapping, countryPrimaryKeyColumns)
	countryInsertCacheMut       sync.RWMutex
	countryInsertCache          = make(map[string]insertCache)
	countryUpdateCacheMut       sync.RWMutex
	countryUpdateCache          = make(map[string]updateCache)
	countryUpsertCacheMut       sync.RWMutex
	countryUpsertCache          = make(map[string]insertCache)
)

var (
	// Force time package dependency for automated UpdatedAt/CreatedAt.
	_ = time.Second
	// Force qmhelper dependency for where clause generation (which doesn't
	// always happen)
	_ = qmhelper.Where
)

var countryAfterSelectHooks []CountryHook

var countryBeforeInsertHooks []CountryHook
var countryAfterInsertHooks []CountryHook

var countryBeforeUpdateHooks []CountryHook
var countryAfterUpdateHooks []CountryHook

var countryBeforeDeleteHooks []CountryHook
var countryAfterDeleteHooks []CountryHook

var countryBeforeUpsertHooks []CountryHook
var countryAfterUpsertHooks []CountryHook

// doAfterSelectHooks executes all "after Select" hooks.
func (o *Country) doAfterSelectHooks(ctx context.Context, exec boil.ContextExecutor) (err error) {
	if boil.HooksAreSkipped(ctx) {
		return nil
	}

	for _, hook := range countryAfterSelectHooks {
		if err := hook(ctx, exec, o); err != nil {
			return err
		}
	}

	return nil
}

// doBeforeInsertHooks executes all "before insert" hooks.
func (o *Country) doBeforeInsertHooks(ctx context.Context, exec boil.ContextExecutor) (err error) {
	if boil.HooksAreSkipped(ctx) {
		return nil
	}

	for _, hook := range countryBeforeInsertHooks {
		if err := hook(ctx, exec, o); err != nil {
			return err
		}
	}

	return nil
}

// doAfterInsertHooks executes all "after Insert" hooks.
func (o *Country) doAfterInsertHooks(ctx context.Context, exec boil.ContextExecutor) (err error) {
	if boil.HooksAreSkipped(ctx) {
		return nil
	}

	for _, hook := range countryAfterInsertHooks {
		if err := hook(ctx, exec, o); err != nil {
			return err
		}
	}

	return nil
}

// doBeforeUpdateHooks executes all "before Update" hooks.
func (o *Country) doBeforeUpdateHooks(ctx context.Context, exec boil.ContextExecutor) (err error) {
	if boil.HooksAreSkipped(ctx) {
		return nil
	}

	for _, hook := range countryBeforeUpdateHooks {
		if err := hook(ctx, exec, o); err != nil {
			return err
		}
	}

	return nil
}

// doAfterUpdateHooks executes all "after Update" hooks.
func (o *Country) doAfterUpdateHooks(ctx context.Context, exec boil.ContextExecutor) (err error) {
	if boil.HooksAreSkipped(ctx) {
		return nil
	}

	for _, hook := range countryAfterUpdateHooks {
		if err := hook(ctx, exec, o); err != nil {
			return err
		}
	}

	return nil
}

// doBeforeDeleteHooks executes all "before Delete" hooks.
func (o *Country) doBeforeDeleteHooks(ctx context.Context, exec boil.ContextExecutor) (err error) {
	if boil.HooksAreSkipped(ctx) {
		return nil
	}

	for _, hook := range countryBeforeDeleteHooks {
		if err := hook(ctx, exec, o); err != nil {
			return err
		}
	}

	return nil
}

// doAfterDeleteHooks executes all "after Delete" hooks.
func (o *Country) doAfterDeleteHooks(ctx context.Context, exec boil.ContextExecutor) (err error) {
	if boil.HooksAreSkipped(ctx) {
		return nil
	}

	for _, hook := range countryAfterDeleteHooks {
		if err := hook(ctx, exec, o); err != nil {
			return err
		}
	}

	return nil
}

// doBeforeUpsertHooks executes all "before Upsert" hooks.
func (o *Country) doBeforeUpsertHooks(ctx context.Context, exec boil.ContextExecutor) (err error) {
	if boil.HooksAreSkipped(ctx) {
		return nil
	}

	for _, hook := range countryBeforeUpsertHooks {
		if err := hook(ctx, exec, o); err != nil {
			return err
		}
	}

	return nil
}

// doAfterUpsertHooks executes all "after Upsert" hooks.
func (o *Country) doAfterUpsertHooks(ctx context.Context, exec boil.ContextExecutor) (err error) {
	if boil.HooksAreSkipped(ctx) {
		return nil
	}

	for _, hook := range countryAfterUpsertHooks {
		if err := hook(ctx, exec, o); err != nil {
			return err
		}
	}

	return nil
}

// AddCountryHook registers your hook function for all future operations.
func AddCountryHook(hookPoint boil.HookPoint, countryHook CountryHook) {
	switch hookPoint {
	case boil.AfterSelectHook:
		countryAfterSelectHooks = append(countryAfterSelectHooks, countryHook)
	case boil.BeforeInsertHook:
		countryBeforeInsertHooks = append(countryBeforeInsertHooks, countryHook)
	case boil.AfterInsertHook:
		countryAfterInsertHooks = append(countryAfterInsertHooks, countryHook)
	case boil.BeforeUpdateHook:
		countryBeforeUpdateHooks = append(countryBeforeUpdateHooks, countryHook)
	case boil.AfterUpdateHook:
		countryAfterUpdateHooks = append(countryAfterUpdateHooks, countryHook)
	case boil.BeforeDeleteHook:
		countryBeforeDeleteHooks = append(countryBeforeDeleteHooks, countryHook)
	case boil.AfterDeleteHook:
		countryAfterDeleteHooks = append(countryAfterDeleteHooks, countryHook)
	case boil.BeforeUpsertHook:
		countryBeforeUpsertHooks = append(countryBeforeUpsertHooks, countryHook)
	case boil.AfterUpsertHook:
		countryAfterUpsertHooks = append(countryAfterUpsertHooks, countryHook)
	}
}

// One returns a single country record from the query.
func (q countryQuery) One(ctx context.Context, exec boil.ContextExecutor) (*Country, error) {
	o := &Country{}

	queries.SetLimit(q.Query, 1)

	err := q.Bind(ctx, exec, o)
	if err != nil {
		if errors.Is(err, sql.ErrNoRows) {
			return nil, sql.ErrNoRows
		}
		return nil, errors.Wrap(err, "models: failed to execute a one query for country")
	}

	if err := o.doAfterSelectHooks(ctx, exec); err != nil {
		return o, err
	}

	return o, nil
}

// All returns all Country records from the query.
func (q countryQuery) All(ctx context.Context, exec boil.ContextExecutor) (CountrySlice, error) {
	var o []*Country

	err := q.Bind(ctx, exec, &o)
	if err != nil {
		return nil, errors.Wrap(err, "models: failed to assign all query results to Country slice")
	}

	if len(countryAfterSelectHooks) != 0 {
		for _, obj := range o {
			if err := obj.doAfterSelectHooks(ctx, exec); err != nil {
				return o, err
			}
		}
	}

	return o, nil
}

// Count returns the count of all Country records in the query.
func (q countryQuery) Count(ctx context.Context, exec boil.ContextExecutor) (int64, error) {
	var count int64

	queries.SetSelect(q.Query, nil)
	queries.SetCount(q.Query)

	err := q.Query.QueryRowContext(ctx, exec).Scan(&count)
	if err != nil {
		return 0, errors.Wrap(err, "models: failed to count country rows")
	}

	return count, nil
}

// Exists checks if the row exists in the table.
func (q countryQuery) Exists(ctx context.Context, exec boil.ContextExecutor) (bool, error) {
	var count int64

	queries.SetSelect(q.Query, nil)
	queries.SetCount(q.Query)
	queries.SetLimit(q.Query, 1)

	err := q.Query.QueryRowContext(ctx, exec).Scan(&count)
	if err != nil {
		return false, errors.Wrap(err, "models: failed to check if country exists")
	}

	return count > 0, nil
}

// Countries retrieves all the records using an executor.
func Countries(mods ...qm.QueryMod) countryQuery {
	mods = append(mods, qm.From("`country`"))
	q := NewQuery(mods...)
	if len(queries.GetSelect(q)) == 0 {
		queries.SetSelect(q, []string{"`country`.*"})
	}

	return countryQuery{q}
}

// FindCountry retrieves a single record by ID with an executor.
// If selectCols is empty Find will return all columns.
func FindCountry(ctx context.Context, exec boil.ContextExecutor, iD int64, selectCols ...string) (*Country, error) {
	countryObj := &Country{}

	sel := "*"
	if len(selectCols) > 0 {
		sel = strings.Join(strmangle.IdentQuoteSlice(dialect.LQ, dialect.RQ, selectCols), ",")
	}
	query := fmt.Sprintf(
		"select %s from `country` where `id`=?", sel,
	)

	q := queries.Raw(query, iD)

	err := q.Bind(ctx, exec, countryObj)
	if err != nil {
		if errors.Is(err, sql.ErrNoRows) {
			return nil, sql.ErrNoRows
		}
		return nil, errors.Wrap(err, "models: unable to select from country")
	}

	if err = countryObj.doAfterSelectHooks(ctx, exec); err != nil {
		return countryObj, err
	}

	return countryObj, nil
}

// Insert a single record using an executor.
// See boil.Columns.InsertColumnSet documentation to understand column list inference for inserts.
func (o *Country) Insert(ctx context.Context, exec boil.ContextExecutor, columns boil.Columns) error {
	if o == nil {
		return errors.New("models: no country provided for insertion")
	}

	var err error
	if !boil.TimestampsAreSkipped(ctx) {
		currTime := time.Now().In(boil.GetLocation())

		if queries.MustTime(o.CreatedAt).IsZero() {
			queries.SetScanner(&o.CreatedAt, currTime)
		}
	}

	if err := o.doBeforeInsertHooks(ctx, exec); err != nil {
		return err
	}

	nzDefaults := queries.NonZeroDefaultSet(countryColumnsWithDefault, o)

	key := makeCacheKey(columns, nzDefaults)
	countryInsertCacheMut.RLock()
	cache, cached := countryInsertCache[key]
	countryInsertCacheMut.RUnlock()

	if !cached {
		wl, returnColumns := columns.InsertColumnSet(
			countryAllColumns,
			countryColumnsWithDefault,
			countryColumnsWithoutDefault,
			nzDefaults,
		)

		cache.valueMapping, err = queries.BindMapping(countryType, countryMapping, wl)
		if err != nil {
			return err
		}
		cache.retMapping, err = queries.BindMapping(countryType, countryMapping, returnColumns)
		if err != nil {
			return err
		}
		if len(wl) != 0 {
			cache.query = fmt.Sprintf("INSERT INTO `country` (`%s`) %%sVALUES (%s)%%s", strings.Join(wl, "`,`"), strmangle.Placeholders(dialect.UseIndexPlaceholders, len(wl), 1, 1))
		} else {
			cache.query = "INSERT INTO `country` () VALUES ()%s%s"
		}

		var queryOutput, queryReturning string

		if len(cache.retMapping) != 0 {
			cache.retQuery = fmt.Sprintf("SELECT `%s` FROM `country` WHERE %s", strings.Join(returnColumns, "`,`"), strmangle.WhereClause("`", "`", 0, countryPrimaryKeyColumns))
		}

		cache.query = fmt.Sprintf(cache.query, queryOutput, queryReturning)
	}

	value := reflect.Indirect(reflect.ValueOf(o))
	vals := queries.ValuesFromMapping(value, cache.valueMapping)

	if boil.IsDebug(ctx) {
		writer := boil.DebugWriterFrom(ctx)
		fmt.Fprintln(writer, cache.query)
		fmt.Fprintln(writer, vals)
	}
	result, err := exec.ExecContext(ctx, cache.query, vals...)

	if err != nil {
		return errors.Wrap(err, "models: unable to insert into country")
	}

	var lastID int64
	var identifierCols []interface{}

	if len(cache.retMapping) == 0 {
		goto CacheNoHooks
	}

	lastID, err = result.LastInsertId()
	if err != nil {
		return ErrSyncFail
	}

	o.ID = int64(lastID)
	if lastID != 0 && len(cache.retMapping) == 1 && cache.retMapping[0] == countryMapping["id"] {
		goto CacheNoHooks
	}

	identifierCols = []interface{}{
		o.ID,
	}

	if boil.IsDebug(ctx) {
		writer := boil.DebugWriterFrom(ctx)
		fmt.Fprintln(writer, cache.retQuery)
		fmt.Fprintln(writer, identifierCols...)
	}
	err = exec.QueryRowContext(ctx, cache.retQuery, identifierCols...).Scan(queries.PtrsFromMapping(value, cache.retMapping)...)
	if err != nil {
		return errors.Wrap(err, "models: unable to populate default values for country")
	}

CacheNoHooks:
	if !cached {
		countryInsertCacheMut.Lock()
		countryInsertCache[key] = cache
		countryInsertCacheMut.Unlock()
	}

	return o.doAfterInsertHooks(ctx, exec)
}

// Update uses an executor to update the Country.
// See boil.Columns.UpdateColumnSet documentation to understand column list inference for updates.
// Update does not automatically update the record in case of default values. Use .Reload() to refresh the records.
func (o *Country) Update(ctx context.Context, exec boil.ContextExecutor, columns boil.Columns) (int64, error) {
	var err error
	if err = o.doBeforeUpdateHooks(ctx, exec); err != nil {
		return 0, err
	}
	key := makeCacheKey(columns, nil)
	countryUpdateCacheMut.RLock()
	cache, cached := countryUpdateCache[key]
	countryUpdateCacheMut.RUnlock()

	if !cached {
		wl := columns.UpdateColumnSet(
			countryAllColumns,
			countryPrimaryKeyColumns,
		)

		if !columns.IsWhitelist() {
			wl = strmangle.SetComplement(wl, []string{"created_at"})
		}
		if len(wl) == 0 {
			return 0, errors.New("models: unable to update country, could not build whitelist")
		}

		cache.query = fmt.Sprintf("UPDATE `country` SET %s WHERE %s",
			strmangle.SetParamNames("`", "`", 0, wl),
			strmangle.WhereClause("`", "`", 0, countryPrimaryKeyColumns),
		)
		cache.valueMapping, err = queries.BindMapping(countryType, countryMapping, append(wl, countryPrimaryKeyColumns...))
		if err != nil {
			return 0, err
		}
	}

	values := queries.ValuesFromMapping(reflect.Indirect(reflect.ValueOf(o)), cache.valueMapping)

	if boil.IsDebug(ctx) {
		writer := boil.DebugWriterFrom(ctx)
		fmt.Fprintln(writer, cache.query)
		fmt.Fprintln(writer, values)
	}
	var result sql.Result
	result, err = exec.ExecContext(ctx, cache.query, values...)
	if err != nil {
		return 0, errors.Wrap(err, "models: unable to update country row")
	}

	rowsAff, err := result.RowsAffected()
	if err != nil {
		return 0, errors.Wrap(err, "models: failed to get rows affected by update for country")
	}

	if !cached {
		countryUpdateCacheMut.Lock()
		countryUpdateCache[key] = cache
		countryUpdateCacheMut.Unlock()
	}

	return rowsAff, o.doAfterUpdateHooks(ctx, exec)
}

// UpdateAll updates all rows with the specified column values.
func (q countryQuery) UpdateAll(ctx context.Context, exec boil.ContextExecutor, cols M) (int64, error) {
	queries.SetUpdate(q.Query, cols)

	result, err := q.Query.ExecContext(ctx, exec)
	if err != nil {
		return 0, errors.Wrap(err, "models: unable to update all for country")
	}

	rowsAff, err := result.RowsAffected()
	if err != nil {
		return 0, errors.Wrap(err, "models: unable to retrieve rows affected for country")
	}

	return rowsAff, nil
}

// UpdateAll updates all rows with the specified column values, using an executor.
func (o CountrySlice) UpdateAll(ctx context.Context, exec boil.ContextExecutor, cols M) (int64, error) {
	ln := int64(len(o))
	if ln == 0 {
		return 0, nil
	}

	if len(cols) == 0 {
		return 0, errors.New("models: update all requires at least one column argument")
	}

	colNames := make([]string, len(cols))
	args := make([]interface{}, len(cols))

	i := 0
	for name, value := range cols {
		colNames[i] = name
		args[i] = value
		i++
	}

	// Append all of the primary key values for each column
	for _, obj := range o {
		pkeyArgs := queries.ValuesFromMapping(reflect.Indirect(reflect.ValueOf(obj)), countryPrimaryKeyMapping)
		args = append(args, pkeyArgs...)
	}

	sql := fmt.Sprintf("UPDATE `country` SET %s WHERE %s",
		strmangle.SetParamNames("`", "`", 0, colNames),
		strmangle.WhereClauseRepeated(string(dialect.LQ), string(dialect.RQ), 0, countryPrimaryKeyColumns, len(o)))

	if boil.IsDebug(ctx) {
		writer := boil.DebugWriterFrom(ctx)
		fmt.Fprintln(writer, sql)
		fmt.Fprintln(writer, args...)
	}
	result, err := exec.ExecContext(ctx, sql, args...)
	if err != nil {
		return 0, errors.Wrap(err, "models: unable to update all in country slice")
	}

	rowsAff, err := result.RowsAffected()
	if err != nil {
		return 0, errors.Wrap(err, "models: unable to retrieve rows affected all in update all country")
	}
	return rowsAff, nil
}

var mySQLCountryUniqueColumns = []string{
	"id",
}

// Upsert attempts an insert using an executor, and does an update or ignore on conflict.
// See boil.Columns documentation for how to properly use updateColumns and insertColumns.
func (o *Country) Upsert(ctx context.Context, exec boil.ContextExecutor, updateColumns, insertColumns boil.Columns) error {
	if o == nil {
		return errors.New("models: no country provided for upsert")
	}
	if !boil.TimestampsAreSkipped(ctx) {
		currTime := time.Now().In(boil.GetLocation())

		if queries.MustTime(o.CreatedAt).IsZero() {
			queries.SetScanner(&o.CreatedAt, currTime)
		}
	}

	if err := o.doBeforeUpsertHooks(ctx, exec); err != nil {
		return err
	}

	nzDefaults := queries.NonZeroDefaultSet(countryColumnsWithDefault, o)
	nzUniques := queries.NonZeroDefaultSet(mySQLCountryUniqueColumns, o)

	if len(nzUniques) == 0 {
		return errors.New("cannot upsert with a table that cannot conflict on a unique column")
	}

	// Build cache key in-line uglily - mysql vs psql problems
	buf := strmangle.GetBuffer()
	buf.WriteString(strconv.Itoa(updateColumns.Kind))
	for _, c := range updateColumns.Cols {
		buf.WriteString(c)
	}
	buf.WriteByte('.')
	buf.WriteString(strconv.Itoa(insertColumns.Kind))
	for _, c := range insertColumns.Cols {
		buf.WriteString(c)
	}
	buf.WriteByte('.')
	for _, c := range nzDefaults {
		buf.WriteString(c)
	}
	buf.WriteByte('.')
	for _, c := range nzUniques {
		buf.WriteString(c)
	}
	key := buf.String()
	strmangle.PutBuffer(buf)

	countryUpsertCacheMut.RLock()
	cache, cached := countryUpsertCache[key]
	countryUpsertCacheMut.RUnlock()

	var err error

	if !cached {
		insert, ret := insertColumns.InsertColumnSet(
			countryAllColumns,
			countryColumnsWithDefault,
			countryColumnsWithoutDefault,
			nzDefaults,
		)

		update := updateColumns.UpdateColumnSet(
			countryAllColumns,
			countryPrimaryKeyColumns,
		)

		if !updateColumns.IsNone() && len(update) == 0 {
			return errors.New("models: unable to upsert country, could not build update column list")
		}

		ret = strmangle.SetComplement(ret, nzUniques)
		cache.query = buildUpsertQueryMySQL(dialect, "`country`", update, insert)
		cache.retQuery = fmt.Sprintf(
			"SELECT %s FROM `country` WHERE %s",
			strings.Join(strmangle.IdentQuoteSlice(dialect.LQ, dialect.RQ, ret), ","),
			strmangle.WhereClause("`", "`", 0, nzUniques),
		)

		cache.valueMapping, err = queries.BindMapping(countryType, countryMapping, insert)
		if err != nil {
			return err
		}
		if len(ret) != 0 {
			cache.retMapping, err = queries.BindMapping(countryType, countryMapping, ret)
			if err != nil {
				return err
			}
		}
	}

	value := reflect.Indirect(reflect.ValueOf(o))
	vals := queries.ValuesFromMapping(value, cache.valueMapping)
	var returns []interface{}
	if len(cache.retMapping) != 0 {
		returns = queries.PtrsFromMapping(value, cache.retMapping)
	}

	if boil.IsDebug(ctx) {
		writer := boil.DebugWriterFrom(ctx)
		fmt.Fprintln(writer, cache.query)
		fmt.Fprintln(writer, vals)
	}
	result, err := exec.ExecContext(ctx, cache.query, vals...)

	if err != nil {
		return errors.Wrap(err, "models: unable to upsert for country")
	}

	var lastID int64
	var uniqueMap []uint64
	var nzUniqueCols []interface{}

	if len(cache.retMapping) == 0 {
		goto CacheNoHooks
	}

	lastID, err = result.LastInsertId()
	if err != nil {
		return ErrSyncFail
	}

	o.ID = int64(lastID)
	if lastID != 0 && len(cache.retMapping) == 1 && cache.retMapping[0] == countryMapping["id"] {
		goto CacheNoHooks
	}

	uniqueMap, err = queries.BindMapping(countryType, countryMapping, nzUniques)
	if err != nil {
		return errors.Wrap(err, "models: unable to retrieve unique values for country")
	}
	nzUniqueCols = queries.ValuesFromMapping(reflect.Indirect(reflect.ValueOf(o)), uniqueMap)

	if boil.IsDebug(ctx) {
		writer := boil.DebugWriterFrom(ctx)
		fmt.Fprintln(writer, cache.retQuery)
		fmt.Fprintln(writer, nzUniqueCols...)
	}
	err = exec.QueryRowContext(ctx, cache.retQuery, nzUniqueCols...).Scan(returns...)
	if err != nil {
		return errors.Wrap(err, "models: unable to populate default values for country")
	}

CacheNoHooks:
	if !cached {
		countryUpsertCacheMut.Lock()
		countryUpsertCache[key] = cache
		countryUpsertCacheMut.Unlock()
	}

	return o.doAfterUpsertHooks(ctx, exec)
}

// Delete deletes a single Country record with an executor.
// Delete will match against the primary key column to find the record to delete.
func (o *Country) Delete(ctx context.Context, exec boil.ContextExecutor) (int64, error) {
	if o == nil {
		return 0, errors.New("models: no Country provided for delete")
	}

	if err := o.doBeforeDeleteHooks(ctx, exec); err != nil {
		return 0, err
	}

	args := queries.ValuesFromMapping(reflect.Indirect(reflect.ValueOf(o)), countryPrimaryKeyMapping)
	sql := "DELETE FROM `country` WHERE `id`=?"

	if boil.IsDebug(ctx) {
		writer := boil.DebugWriterFrom(ctx)
		fmt.Fprintln(writer, sql)
		fmt.Fprintln(writer, args...)
	}
	result, err := exec.ExecContext(ctx, sql, args...)
	if err != nil {
		return 0, errors.Wrap(err, "models: unable to delete from country")
	}

	rowsAff, err := result.RowsAffected()
	if err != nil {
		return 0, errors.Wrap(err, "models: failed to get rows affected by delete for country")
	}

	if err := o.doAfterDeleteHooks(ctx, exec); err != nil {
		return 0, err
	}

	return rowsAff, nil
}

// DeleteAll deletes all matching rows.
func (q countryQuery) DeleteAll(ctx context.Context, exec boil.ContextExecutor) (int64, error) {
	if q.Query == nil {
		return 0, errors.New("models: no countryQuery provided for delete all")
	}

	queries.SetDelete(q.Query)

	result, err := q.Query.ExecContext(ctx, exec)
	if err != nil {
		return 0, errors.Wrap(err, "models: unable to delete all from country")
	}

	rowsAff, err := result.RowsAffected()
	if err != nil {
		return 0, errors.Wrap(err, "models: failed to get rows affected by deleteall for country")
	}

	return rowsAff, nil
}

// DeleteAll deletes all rows in the slice, using an executor.
func (o CountrySlice) DeleteAll(ctx context.Context, exec boil.ContextExecutor) (int64, error) {
	if len(o) == 0 {
		return 0, nil
	}

	if len(countryBeforeDeleteHooks) != 0 {
		for _, obj := range o {
			if err := obj.doBeforeDeleteHooks(ctx, exec); err != nil {
				return 0, err
			}
		}
	}

	var args []interface{}
	for _, obj := range o {
		pkeyArgs := queries.ValuesFromMapping(reflect.Indirect(reflect.ValueOf(obj)), countryPrimaryKeyMapping)
		args = append(args, pkeyArgs...)
	}

	sql := "DELETE FROM `country` WHERE " +
		strmangle.WhereClauseRepeated(string(dialect.LQ), string(dialect.RQ), 0, countryPrimaryKeyColumns, len(o))

	if boil.IsDebug(ctx) {
		writer := boil.DebugWriterFrom(ctx)
		fmt.Fprintln(writer, sql)
		fmt.Fprintln(writer, args)
	}
	result, err := exec.ExecContext(ctx, sql, args...)
	if err != nil {
		return 0, errors.Wrap(err, "models: unable to delete all from country slice")
	}

	rowsAff, err := result.RowsAffected()
	if err != nil {
		return 0, errors.Wrap(err, "models: failed to get rows affected by deleteall for country")
	}

	if len(countryAfterDeleteHooks) != 0 {
		for _, obj := range o {
			if err := obj.doAfterDeleteHooks(ctx, exec); err != nil {
				return 0, err
			}
		}
	}

	return rowsAff, nil
}

// Reload refetches the object from the database
// using the primary keys with an executor.
func (o *Country) Reload(ctx context.Context, exec boil.ContextExecutor) error {
	ret, err := FindCountry(ctx, exec, o.ID)
	if err != nil {
		return err
	}

	*o = *ret
	return nil
}

// ReloadAll refetches every row with matching primary key column values
// and overwrites the original object slice with the newly updated slice.
func (o *CountrySlice) ReloadAll(ctx context.Context, exec boil.ContextExecutor) error {
	if o == nil || len(*o) == 0 {
		return nil
	}

	slice := CountrySlice{}
	var args []interface{}
	for _, obj := range *o {
		pkeyArgs := queries.ValuesFromMapping(reflect.Indirect(reflect.ValueOf(obj)), countryPrimaryKeyMapping)
		args = append(args, pkeyArgs...)
	}

	sql := "SELECT `country`.* FROM `country` WHERE " +
		strmangle.WhereClauseRepeated(string(dialect.LQ), string(dialect.RQ), 0, countryPrimaryKeyColumns, len(*o))

	q := queries.Raw(sql, args...)

	err := q.Bind(ctx, exec, &slice)
	if err != nil {
		return errors.Wrap(err, "models: unable to reload all in CountrySlice")
	}

	*o = slice

	return nil
}

// CountryExists checks if the Country row exists.
func CountryExists(ctx context.Context, exec boil.ContextExecutor, iD int64) (bool, error) {
	var exists bool
	sql := "select exists(select 1 from `country` where `id`=? limit 1)"

	if boil.IsDebug(ctx) {
		writer := boil.DebugWriterFrom(ctx)
		fmt.Fprintln(writer, sql)
		fmt.Fprintln(writer, iD)
	}
	row := exec.QueryRowContext(ctx, sql, iD)

	err := row.Scan(&exists)
	if err != nil {
		return false, errors.Wrap(err, "models: unable to check if country exists")
	}

	return exists, nil
}

まとめ

Gorm
- 生SQLの実行は可能
  - 生SQLの取得結果を、Iteratorを使用して、構造体にいれなけれなばいけない
- 参考になる記事などが多い
- DBからコードを生成できない
- オートマイグレーションあり
XORM
- 生SQLの実行は可能
  - 生SQLの取得結果を、一括で構造体に入れられる
- 参考になる記事などが少なさそうかも
- DBからコードを生成できそう
- オートマイグレーションあり
SQLBoiler
- 生SQLの実行は可能
  - 生SQLの取得結果を、一括で構造体に入れられる
- 参考になる記事などが少なさそうかも
- DBからコードを生成できる
- オートマイグレーションなし
- 実装がDBから生成したテーブル主体のクラスに依存する

どれも使いやすそうな感じだと思いました。
自分が現在担当しているプロジェクトでは、公式のドキュメントがわかりやすいgormを採用しました。
また、DBから構造体を生成するのが手間なのですが、GORM/GENというツールを使用しています。
https://github.com/go-gorm/gen

最後に

現在、レスキューナウでは、災害情報の提供、災害情報を活用した安否確認サービスなどのWebサービスの開発エンジニアを募集しています！
社員・フリーランスに関わらず、参画後に安心してご活躍できることを目指し、応募された方の特性・ご希望にマッチしたチームをご紹介します。
ちょっと話を聞いてみたい、ぜひ応募したい、など、当社にご興味を持っていただけましたら、お気軽にエントリーください！！