func encodeColumnInfoToLattice(ci *model.ColumnInfo) Tuple {
	return Tuple{
		MaybeSingletonInterface(ci.DefaultValue),
		Singleton(ci.GeneratedExprString),
		Singleton(ci.GeneratedStored),
		Type(&ci.FieldType),
	}
}
encodeColumnInfoToLattice collects the necessary information for comparing a column.
package schemacmp
import (
	"sort"
	"strings"
	"github.com/pingcap/tidb/parser/format"
	"github.com/pingcap/tidb/parser/model"
	"github.com/pingcap/tidb/parser/mysql"
	"github.com/pingcap/tidb/parser/types"
)
const (
	columnInfoTupleIndexDefaultValue = iota
	columnInfoTupleIndexGeneratedExprString
	columnInfoTupleIndexGeneratedStored
	columnInfoTupleIndexFieldTypes
)