func (ct ColumnType) Nullable() (nullable bool, ok bool) {
	if ct.NullableValue.Valid {
		return ct.NullableValue.Bool, true
	}
	return ct.SQLColumnType.Nullable()
}

// Unique reports whether the column may be unique.
func (ct ColumnType) Unique() (unique bool, ok bool) {
	return ct.UniqueValue.Bool, ct.UniqueValue.Valid
}

// ScanType returns a Go type suitable for scanning into using Rows.Scan.

	// ErrPreloadNotAllowed preload is not allowed when count is used
	ErrPreloadNotAllowed = errors.New("preload is not allowed when count is used")
	// ErrDuplicatedKey occurs when there is a unique key constraint violation
	ErrDuplicatedKey = errors.New("duplicated key not allowed")
	// ErrForeignKeyViolated occurs when there is a foreign key constraint violation

		FieldF2 string `gorm:"uniqueIndex:uniq_field_f1_f2;"`

		FieldG string `gorm:"unique;uniqueIndex"` // unique and uniqueIndex

		FieldH1 string `gorm:"unique;uniqueIndex:uniq_field_h1_h2"` // unique and mul uniqueIndex
		FieldH2 string `gorm:"uniqueIndex:uniq_field_h1_h2"`        // unique and mul uniqueIndex
	}
	indexSchema, err := schema.Parse(&IndexTest{}, &sync.Map{}, schema.NamingStrategy{})

							return
						}
						subName = composite
					}
					name = field.Schema.namer.IndexName(
						field.Schema.Table, subName)
				}

				if (k == "UNIQUEINDEX") || settings["UNIQUE"] != "" {
					settings["CLASS"] = "UNIQUE"
				}

				priority, err := strconv.Atoi(settings["PRIORITY"])
				if err != nil {
					priority = 10
				}

				indexes = append(indexes, Index{
					Name:    name,

func TestSupportedDialectorWithErrForeignKeyViolated(t *testing.T) {
	tidbSkip(t, "not support the foreign key feature")

	type City struct {
		gorm.Model
		Name string `gorm:"unique"`
	}

	type Museum struct {
		gorm.Model
		Name   string `gorm:"unique"`
		CityID uint
		City   City `gorm:"Constraint:OnUpdate:CASCADE,OnDelete:CASCADE;FOREIGNKEY:CityID;References:ID"`
	}

	}

	if name := DB.Dialector.Name(); name == "postgres" {
		stmt := gorm.Statement{DB: DB}
		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")

			Name:  "uni_user_uniques_name1",
			Field: &schema.Field{Name: "Name1", Unique: true},
		},
	}
	for k, result := range results {
		v, ok := constraints[k]
		if !ok {
			t.Errorf("Failed to found unique constraint %v from parsed constraints %+v", k, constraints)
		}
		tests.AssertObjEqual(t, result, v, "Name")
		tests.AssertObjEqual(t, result.Field, v.Field, "Name", "Unique", "UniqueIndex")
	}

package tests_test

import (
	"testing"
	"time"

	"gorm.io/gorm"
)

func TestDefaultValue(t *testing.T) {
	type Harumph struct {
		gorm.Model
		Email   string    `gorm:"not null;index:,unique"`
		Name    string    `gorm:"notNull;default:foo"`
		Name2   string    `gorm:"size:233;not null;default:'foo'"`
		Name3   string    `gorm:"size:233;notNull;default:''"`
		Age     int       `gorm:"default:18"`

	Serializer             SerializerInterface
	NewValuePool           FieldNewValuePool

	// In some db (e.g. MySQL), Unique and UniqueIndex are indistinguishable.
	// When a column has a (not Mul) UniqueIndex, Migrator always reports its gorm.ColumnType is Unique.
	// It causes field unnecessarily migration.
	// Therefore, we need to record the UniqueIndex on this column (exclude Mul UniqueIndex) for MigrateColumnUnique.

			PkgPath: ownField.StructField.PkgPath,
			Type:    ownField.StructField.Type,
			Tag: removeSettingFromTag(appendSettingFromTag(ownField.StructField.Tag, "primaryKey"),
				"column", "autoincrement", "index", "unique", "uniqueindex"),
		})
	}

	for idx, relField := range refForeignFields {
		joinFieldName := strings.Title(relation.FieldSchema.Name) + relField.Name

		if _, ok := ownFieldsMap[joinFieldName]; ok {