// 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)
	Explain(sql string, vars ...interface{}) string
}

// Plugin GORM plugin interface
type Plugin interface {
	Name() string

func (DummyDialector) DefaultValueOf(field *schema.Field) clause.Expression {
	return clause.Expr{SQL: "DEFAULT"}
}

func (DummyDialector) Migrator(*gorm.DB) gorm.Migrator {
	return nil
}

func (DummyDialector) BindVarTo(writer clause.Writer, stmt *gorm.Statement, v interface{}) {
	writer.WriteByte('?')
}

func (DummyDialector) QuoteTo(writer clause.Writer, str string) {
	var (
		underQuoted, selfQuoted bool

func (d testDialector) DataTypeOf(*schema.Field) string                { return "" }
func (d testDialector) DefaultValueOf(*schema.Field) clause.Expression { return clause.Expr{} }
func (d testDialector) BindVarTo(writer clause.Writer, stmt *gorm.Statement, v interface{}) {
	// write a simple placeholder
	writer.WriteByte('?')
}
func (d testDialector) QuoteTo(writer clause.Writer, s string)         { writer.WriteString(s) }