code: public ColumnModel singleIndex(String indexName) {
  		makeSureTableModelExist();
  		DialectException.assureNotEmpty(indexName, "indexName can not be empty");
  		this.tableModel.index(indexName).columns(this.getColumnName());
  		return this;
  	}
docs: A shortcut method to add a index for single column, for multiple columns
  index please use tableModel.index() method