### Migration

Check out the [Pydantic migration guide](https://docs.pydantic.dev/2.0/migration/).

For the things that need changes in your Pydantic models, the Pydantic team built [`bump-pydantic`](https://github.com/pydantic/bump-pydantic).

* Context, Prepared Statement Mode, DryRun Mode
* Batch Insert, FindInBatches, Find To Map
* SQL Builder, Upsert, Locking, Optimizer/Index/Comment Hints, NamedArg, Search/Update/Create with SQL Expr
* Composite Primary Key
* Auto Migrations
* Logger
* Extendable, flexible plugin API: Database Resolver (Multiple Databases, Read/Write Splitting) / Prometheus…
* Every feature comes with tests
* Developer Friendly

## Getting Started

	}

	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 {
		t.Fatalf("failed to migrate cities table, got error: %v", err)
	}

	err = db.Create(&City{Name: "Kabul"}).Error
	if err != nil {

package migrator

import "database/sql"

// Index implements gorm.Index interface
type Index struct {
	TableName       string
	NameValue       string
	ColumnList      []string
	PrimaryKeyValue sql.NullBool
	UniqueValue     sql.NullBool
	OptionValue     string
}

// Table return the table name of the index.
func (idx Index) Table() string {
	return idx.TableName
}

// Name return the name of the index.

		stmt.Parse(&Blog{})
		stmt.Schema.LookUpField("ID").Unique = true
		stmt.Parse(&Tag{})
		stmt.Schema.LookUpField("ID").Unique = true
		// postgers only allow unique constraint matching given keys
	}

	DB.Migrator().DropTable(&Blog{}, &Tag{}, "blog_tags", "locale_blog_tags", "shared_blog_tags")
	if err := DB.AutoMigrate(&Blog{}, &Tag{}); err != nil {
		t.Fatalf("Failed to auto migrate, got error: %v", err)
	}

	blog := Blog{

		Name3   string    `gorm:"size:233;notNull;default:''"`
		Age     int       `gorm:"default:18"`
		Created time.Time `gorm:"default:2000-01-02"`
		Enabled bool      `gorm:"default:true"`
	}

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

	if err := DB.AutoMigrate(&Harumph{}); err != nil {
		t.Fatalf("Failed to migrate with default value, got error: %v", err)
	}

	harumph := Harumph{Email: "******@****.***"}

package migrator

import (
	"database/sql"
	"reflect"
)

// ColumnType column type implements ColumnType interface
type ColumnType struct {
	SQLColumnType      *sql.ColumnType
	NameValue          sql.NullString
	DataTypeValue      sql.NullString
	ColumnTypeValue    sql.NullString
	PrimaryKeyValue    sql.NullBool
	UniqueValue        sql.NullBool
	AutoIncrementValue sql.NullBool
	LengthValue        sql.NullInt64

		}

		for _, pet := range pets {
			CheckPet(t, *pet, *pet)
		}
	})
}

func TestCreateEmptyStruct(t *testing.T) {
	type EmptyStruct struct {
		ID uint
	}
	DB.Migrator().DropTable(&EmptyStruct{})

	if err := DB.AutoMigrate(&EmptyStruct{}); err != nil {
		t.Errorf("no error should happen when auto migrate, but got %v", err)
	}

	Age        *time.Time
	unexported string // unexported value
	CreatedAt  time.Time
	UpdatedAt  time.Time
}

func TestNonStdPrimaryKeyAndDefaultValues(t *testing.T) {
	DB.Migrator().DropTable(&Animal{})
	if err := DB.AutoMigrate(&Animal{}); err != nil {
		t.Fatalf("no error should happen when migrate but got %v", err)
	}

	animal := Animal{Name: "Ferdinand"}
	DB.Save(&animal)

	ID   uint
	Name string
}

type PersonAddress struct {
	PersonID  int
	AddressID int
	CreatedAt time.Time
	DeletedAt gorm.DeletedAt
}

func TestOverrideJoinTable(t *testing.T) {
	DB.Migrator().DropTable(&Person{}, &Address{}, &PersonAddress{})

	if err := DB.SetupJoinTable(&Person{}, "Addresses", &PersonAddress{}); err != nil {
		t.Fatalf("Failed to setup join table for person, got error %v", err)
	}