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.