src/Helper/TableManipulator.php
public function addIndex($strTableName, $strIndexType, $strColName)
    {
        $this->checkColumnExists($strTableName, $strColName);
        $this->connection->query(
            sprintf(
                self::STATEMENT_ADD_INDEX_COLUMN,
                $strTableName,
                $strIndexType,
                $strColName
            )
        );
    }
public function addIndex($strTableName, $strIndexType, $strColName)
    {
        $this->checkColumnExists($strTableName, $strColName);
        $this->connection->query(
            sprintf(
                self::STATEMENT_ADD_INDEX_COLUMN,
                $strTableName,
                $strIndexType,
                $strColName
            )
        );
    }
Add a index to given tablename for specified columnname

@param string $strTableName The table name.

@param string $strIndexType The index type.

@param string $strColName   The column name to add a index.

@return void

@throws \Exception If an invalid table name has been passed or the table does not exist, the column name is
invalid or the column does not exist.