db, err := OpenTestConnection(&gorm.Config{TranslateError: true})
	if err != nil {
		t.Fatalf("failed to connect database, got error %v", err)
	}

	dialectors := map[string]bool{"sqlite": true, "postgres": true, "mysql": true, "sqlserver": true}
	if supported, found := dialectors[db.Dialector.Name()]; !(found && supported) {
		return
	}

	DB.Migrator().DropTable(&City{})

	if err = db.AutoMigrate(&City{}); err != nil {

	if err == nil {
		t.Fatalf("should returns error but got nil")
	}
}

func TestReturningWithNullToZeroValues(t *testing.T) {
	dialect := DB.Dialector.Name()
	switch dialect {
	case "mysql", "sqlserver":
		// these dialects do not support the "returning" clause
		return
	default:
		// This user struct will leverage the existing users table, but override
		// the Name field to default to null.

	sql := DB.Dialector.Explain(stmt.SQL.String(), stmt.Vars...)
	if !regexp.MustCompile(`.*age.*=8,`).MatchString(sql) {
		t.Errorf("Failed to generate sql, got %v", sql)
	}

	stmt = dryRunDB.Model(&user).Where("id = ?", 1).Updates(map[string]interface{}{"age": ageUint64(10241024)}).Statement
	sql = DB.Dialector.Explain(stmt.SQL.String(), stmt.Vars...)

package gorm

import (
	"context"
	"database/sql"

	"gorm.io/gorm/clause"
	"gorm.io/gorm/schema"
)

// Dialector GORM database dialector
type Dialector interface {
	Name() string
	Initialize(*DB) error
	Migrator(db *DB) Migrator
	DataTypeOf(*schema.Field) string
	DefaultValueOf(*schema.Field) clause.Expression
	BindVarTo(writer clause.Writer, stmt *Statement, v interface{})
	QuoteTo(clause.Writer, string)

	}

	if config.Dialector != nil {
		err = config.Dialector.Initialize(db)

		if err != nil {
			if db, _ := db.DB(); db != nil {
				_ = db.Close()
			}
		}

		if config.TranslateError {
			if _, ok := db.Dialector.(ErrorTranslator); !ok {

	"time"

	"github.com/google/uuid"
	"github.com/lib/pq"
	"gorm.io/gorm"
	"gorm.io/gorm/clause"
	. "gorm.io/gorm/utils/tests"
)

func TestPostgresReturningIDWhichHasStringType(t *testing.T) {
	if DB.Dialector.Name() != "postgres" {
		t.Skip()
	}

	type Yasuo struct {
		ID        string `gorm:"default:gen_random_uuid()"`
		Name      string
		CreatedAt time.Time `gorm:"type:TIMESTAMP WITHOUT TIME ZONE"`

import (
	"fmt"
	"testing"

	"gorm.io/driver/mysql"
	"gorm.io/gorm"
)

func TestWithSingleConnection(t *testing.T) {
	expectedName := "test"
	var actualName string

	setSQL, getSQL := getSetSQL(DB.Dialector.Name())
	if len(setSQL) == 0 || len(getSQL) == 0 {
		return
	}

	err := DB.Connection(func(tx *gorm.DB) error {
		if err := tx.Exec(setSQL, expectedName).Error; err != nil {
			return err
		}

		}
	}
}

// only sqlite, postgres, sqlserver support returning
func TestSoftDeleteReturning(t *testing.T) {
	if DB.Dialector.Name() != "sqlite" && DB.Dialector.Name() != "postgres" && DB.Dialector.Name() != "sqlserver" {
		return
	}

	users := []*User{
		GetUser("delete-returning-1", Config{}),
		GetUser("delete-returning-2", Config{}),

		writer.WriteByte(')')
	case clause.Expr:
		v.Build(stmt)
	case string:
		stmt.DB.Dialector.QuoteTo(writer, v)
	case []string:
		writer.WriteByte('(')
		for idx, d := range v {
			if idx > 0 {
				writer.WriteByte(',')
			}
			stmt.DB.Dialector.QuoteTo(writer, d)
		}
		writer.WriteByte(')')
	default:
		stmt.DB.Dialector.QuoteTo(writer, fmt.Sprint(field))
	}
}

// Quote returns quoted value

		t.Fatalf("Found deleted column")
	}
}

func TestMigrateColumns(t *testing.T) {
	tidbSkip(t, "use another test case")

	sqlite := DB.Dialector.Name() == "sqlite"
	sqlserver := DB.Dialector.Name() == "sqlserver"

	type ColumnStruct struct {
		gorm.Model
		Name  string
		Age   int    `gorm:"default:18;comment:my age"`
		Code  string `gorm:"unique;comment:my code;"`