/**
 * Query the database.
 *
 * @param sql
 *            The query statement
 * @return List of rows returned by the query.
 */
public List<Map<String, Object>> query(String sql) {
    return this.query(sql, null);
}

/**
 * Query the database.
 *
 * @param sql
 *            The query statement
 * @param params
 *            The prepared statement parameters (in order).
 * @return List of rows returned by the query.
 */
public List<Map<String, Object>> query(String sql, Object[] params) {
    final String METHODNAME = "query";
    List<Map<String, Object>> resList = null;

    try {
        if (conn != null && !conn.isClosed()) {
            resList = new ArrayList<Map<String, Object>>();

            PreparedStatement stmt = conn.prepareStatement(sql);
            if (params != null && params.length > 0) {
                for (int i = 1; i <= params.length; i++) { // 1 based, not 0
                    stmt.setObject(i, params[i - 1]);
                }
            }

            ResultSet res = stmt.executeQuery(sql);

            while (res.next()) {
                Map<String, Object> row = new HashMap<String, Object>();

                for (int i = 1; i <= res.getMetaData().getColumnCount(); i++) {
                    String key = res.getMetaData().getColumnName(i);
                    Object val = res.getObject(i);
                    row.put(key, val);
                    resList.add(row);
                }
            }

        } else {
            logger.log(LogLevel.ALL, CLASSNAME, METHODNAME, "Attempted to run query when "
                    + "there was no established connection to the database.");
        }
    } catch (Throwable e) {
        logger.log(LogLevel.ERROR, CLASSNAME, METHODNAME,
                "An error occurred when trying to run the query.");
    }

    return resList;
}