code: func StrColumn(
  	name string,
  	charset Charset,
  	collation Collation,
  	nullable NullableColumn) NonAliasColumn {
  
  	if !validIdentifierName(name) {
  		panic("Invalid column name in str column")
  	}
  	sc := &stringColumn{charset: charset, collation: collation}
  	sc.name = name
  	sc.nullable = nullable
  	return sc
  }
docs: // Representation of VARCHAR/TEXT columns
  // This function will panic if name is not valid