ErrMissingWhereClause = errors.New("WHERE conditions required")
	// ErrUnsupportedRelation unsupported relations
	ErrUnsupportedRelation = errors.New("unsupported relations")
	// ErrPrimaryKeyRequired primary keys required
	ErrPrimaryKeyRequired = errors.New("primary key required")
	// ErrModelValueRequired model value required
	ErrModelValueRequired = errors.New("model value required")

type ViewOption struct {
	Replace     bool   // If true, exec `CREATE`. If false, exec `CREATE OR REPLACE`
	CheckOption string // optional. e.g. `WITH [ CASCADED | LOCAL ] CHECK OPTION`
	Query       *DB    // required subquery.
}

// ColumnType column type interface
type ColumnType interface {
	Name() string
	DatabaseTypeName() string                 // varchar
	ColumnType() (columnType string, ok bool) // varchar(64)