package schema

import (
	"gorm.io/gorm/clause"
)

// ConstraintInterface database constraint interface
type ConstraintInterface interface {
	GetName() string
	Build() (sql string, vars []interface{})
}

// GormDataTypeInterface gorm data type interface
type GormDataTypeInterface interface {
	GormDataType() string
}

// FieldNewValuePool field new scan value pool
type FieldNewValuePool interface {
	Get() interface{}

		gorm.Model
		SomeID  string
		OtherID string
		Data    string
	}

	DB.Migrator().DropTable(&Thing{})
	DB.Migrator().CreateTable(&Thing{})
	if err := DB.Exec("ALTER TABLE things ADD CONSTRAINT some_id_other_id_unique UNIQUE (some_id, other_id)").Error; err != nil {
		t.Error(err)
	}

	thing := Thing{
		SomeID:  "1234",
		OtherID: "1234",
		Data:    "something",
	}

	DB.Create(&thing)

		Name    string
		Profile Profile `gorm:"Constraint:OnUpdate:CASCADE,OnDelete:CASCADE;FOREIGNKEY:MemberID;References:Refer"`
	}

	DB.Migrator().DropTable(&Profile{}, &Member{})

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

	member := Member{Refer: 1, Name: "foreign_key_constraints", Profile: Profile{Name: "my_profile"}}

	DB.Create(&member)

	}

	expectedConstraintName := "fk_my_schema_a_very_very_very_very_very_very_very_very_l4db13eec"
	constraint := s.Relationships.Relations["Author"].ParseConstraint()

	if constraint.Name != expectedConstraintName {
		t.Fatalf(
			"expected constraint name %s, got %s",
			expectedConstraintName,
			constraint.Name,
		)
	}

		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")
	if err := DB.AutoMigrate(&Blog{}, &Tag{}); err != nil {

  }

  @Override
  protected Map<Class<? extends @NonNull B>, B> delegate() {
    return delegate;
  }

  /**
   * Wraps the {@code setValue} implementation of an {@code Entry} to enforce the class constraint.
   */
  private static <B extends @Nullable Object> Entry<Class<? extends @NonNull B>, B> checkedEntry(
      final Entry<Class<? extends @NonNull B>, B> entry) {

	DropColumn(dst interface{}, field string) error
	AlterColumn(dst interface{}, field string) error
	MigrateColumn(dst interface{}, field *schema.Field, columnType ColumnType) error
	// MigrateColumnUnique migrate column's UNIQUE constraint, it's part of MigrateColumn.
	MigrateColumnUnique(dst interface{}, field *schema.Field, columnType ColumnType) error
	HasColumn(dst interface{}, field string) bool
	RenameColumn(dst interface{}, oldName, field string) error

	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"`
	}

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

Then I contributed to it, to make it fully compliant with JSON Schema, to support different ways to define constraint declarations, and to improve editor support (type checks, autocompletion) based on the tests in several editors.

import javax.annotation.CheckForNull;
import org.checkerframework.checker.nullness.qual.Nullable;

/**
 * A bimap (or "bidirectional map") is a map that preserves the uniqueness of its values as well as
 * that of its keys. This constraint enables bimaps to support an "inverse view", which is another
 * bimap containing the same entries as this bimap but with reversed keys and values.
 *
 * <h3>Implementations</h3>
 *
 * <ul>