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.
func (ct ColumnType) ScanType() reflect.Type {
	if ct.ScanTypeValue != nil {
		return ct.ScanTypeValue
	}
	return ct.SQLColumnType.ScanType()
}

// Comment returns the comment of current column.
func (ct ColumnType) Comment() (value string, ok bool) {

	AutoIncrement() (isAutoIncrement bool, ok bool)
	Length() (length int64, ok bool)
	DecimalSize() (precision int64, scale int64, ok bool)
	Nullable() (nullable bool, ok bool)
	Unique() (unique bool, ok bool)
	ScanType() reflect.Type
	Comment() (value string, ok bool)
	DefaultValue() (value string, ok bool)
}

type Index interface {
	Table() string
	Name() string
	Columns() []string