将数据发布到PHP API

我是PHP和SQL编码的新手，并且一直试图将数据发布到数据库中，但是当使用Postman检查响应时，我得到了else响应，我真的不知道为什么，因为我的POST数据正是所需的数据。

这是截图

非常感谢您对我的帮助！

根据要求，这里是代码

<?php
    require("../database_android.php");

    if(isset($_POST["package_name"]) &&  $_POST["package_name"] != "") {
        $package_name = mysql_real_escape_string($_POST["package_name"]);
    } else {
        echo "package_name missing";
        return;
    }

    if(isset($_POST["app_name"]) &&  $_POST["app_name"] != "") {
        $app_name = mysql_real_escape_string($_POST["app_name"]);
    } else {
        echo "app_name missing";
        return;
    }

    if(isset($_POST["activity"]) &&  $_POST["activity"] != "") {
        $activity = mysql_real_escape_string($_POST["activity"]);
    } else {
        echo "activity missing";
        return;
    }

    if(isset($_POST["activity_name"]) &&  $_POST["activity_name"] != "") {
        $activity_name = mysql_real_escape_string($_POST["activity_name"]);
    } else {
        echo "activity_name missing";
        return;
    }

    if(isset($_POST["component_info"]) &&  $_POST["component_info"] != "") {
        $component_info = mysql_real_escape_string($_POST["component_info"]);
    } else {
        echo "component_info missing";
        return;
    }



    $application_id = already_exists_application($package_name);
    if($application_id < 0) {
        mysql_query("INSERT INTO androidactivities_application (package_name, app_name) VALUES ('". $package_name ."', '". $app_name ."')");
        $application_id = already_exists_application($package_name);
    }

    $componentinfo_id = already_exists_componentinfo($application_id, $component_info);
    if($componentinfo_id < 0 && $application_id > 0) {
        mysql_query("INSERT INTO androidactivities_componentinfo (application_id, activity, activity_name, component_info) VALUES ('". $application_id ."', '". $activity ."', '". $activity_name ."', '". $component_info ."')");

        echo "successful";
    } else {
        echo "exists";
    }
?>

<?php
    function already_exists_application($package_name) {
        $result = mysql_query("SELECT * from androidactivities_application WHERE package_name = '".$package_name."'");

        if($row = mysql_fetch_object($result)) {
                return $row -> application_id;
        }
        else {
            return -1;
        }
    }

    function already_exists_componentinfo($application_id, $component_info) {
        $result = mysql_query("SELECT * from androidactivities_componentinfo WHERE application_id = '".$application_id."' AND component_info = '".$component_info."'");

        if($row = mysql_fetch_object($result)) {
                return $row -> componeninfo_id;
        }
        else {
            return -1;
        }
    }
?>