code: protected void parseColumns( DdlTokenStream tokens,
                                   AstNode tableNode,
                                   boolean isAlterTable ) throws ParsingException {
          parseColumns(tokens, tableNode, (isAlterTable ? TYPE_ALTER_COLUMN_DEFINITION : TYPE_ADD_COLUMN_DEFINITION));
      }
docs: Overloaded version of method with default mixin type set to {@link StandardDdlLexicon#TYPE_ADD_COLUMN_DEFINITION}
  
  @param tokens the tokenized {@link DdlTokenStream} of the DDL input content; may not be null
  @param tableNode
  @param isAlterTable
  @throws ParsingException