<?php
function exec_query($sql, $params = []) {
    $username = 's1165683';
    $password = '11656830';
    $conn_info = "(DESCRIPTION=(ADDRESS=(PROTOCOL=TCP) " .
                 "(HOST = oracleacademy.ouhk.edu.hk)(PORT=8998)) " .
                 "(CONNECT_DATA=(SERVER=DEDICATED) " .
                 "(SID=db1011)))";
    $conn = oci_connect($username, $password, $conn_info);
    if (!$conn) {
        $e = oci_error();
        die("Fatal: Unable to connect to the database: {$e['message']}");
    }
    $stmt = oci_parse($conn, $sql);
    if (!$stmt) {
        die("Fatal: Failed to parse SQL statement: $sql");
    }
    foreach ($params as $key => &$value) {
        if (!oci_bind_by_name($stmt, ":" . $key, $value)) {
            die ("Fatal: Failed to bind variable $key: $sql");
        }
    }
    if (!@oci_execute($stmt)) {
        $err = oci_error($stmt);
        die("Fatal: Unable to execute SQL statement: {$e['message']}");
    }
    $result = [];
    while ($raw_row = @oci_fetch_assoc($stmt)) {
        $row = [];
        foreach ($raw_row as $k => $v) {
            $row[strtolower($k)] = $v;
        }
        $result[] = $row;
    }
    oci_free_statement($stmt);
    oci_close($conn);
    return $result;
}