= UC0008 - Volunteer for Event Session =

'''Initiating actor:''' Member

A Member volunteers for a selected event session. The scenario uses Dario Petreski volunteering for the Company Stands session at MFS during Job Fair 2026.

== Scenario ==

1. The Member opens the volunteer opportunities for Job Fair 2026.

2. The application lists event sessions and volunteer coverage.

{{{#!sql
SELECT
    es.est_name,
    es.es_start_time,
    es.location,
    es.es_title,
    est.needed_no_volunteers,
    COUNT(v.student_index) AS assigned_volunteers,
    GREATEST(est.needed_no_volunteers - COUNT(v.student_index), 0) AS missing_volunteers
FROM event_sessions es
JOIN event_session_types est
    ON est.est_name = es.est_name
LEFT JOIN volunteers v
    ON v.et_name = es.et_name
   AND v.event_title = es.event_title
   AND v.event_start_time = es.event_start_time
   AND v.est_name = es.est_name
   AND v.es_start_time = es.es_start_time
   AND v.location = es.location
WHERE es.et_name = 'Job Fair'
  AND es.event_title = 'Job Fair 2026'
  AND es.event_start_time = TIMESTAMP '2026-03-23 09:00:00'
GROUP BY
    es.est_name,
    es.es_start_time,
    es.location,
    es.es_title,
    est.needed_no_volunteers
ORDER BY es.es_start_time, es.location, es.est_name;
}}}

3. The Member chooses the Company Stands session at MFS.

4. The application checks whether the member already volunteers at the same start time.

{{{#!sql
SELECT
    v.et_name,
    v.event_title,
    v.est_name,
    v.es_start_time,
    v.location,
    v.volunteer_role
FROM volunteers v
WHERE v.student_index = 230024
  AND v.es_start_time = TIMESTAMP '2026-03-24 10:00:00';
}}}

5. The application stores the volunteer record.

{{{#!sql
INSERT INTO volunteers (
    student_index,
    et_name,
    event_title,
    event_start_time,
    est_name,
    es_start_time,
    location,
    volunteer_role
)
VALUES (
    230024,
    'Job Fair',
    'Job Fair 2026',
    TIMESTAMP '2026-03-23 09:00:00',
    'Company Stands',
    TIMESTAMP '2026-03-24 10:00:00',
    'MFS',
    'stand support'
);
}}}

6. The application refreshes the volunteer list for the selected session.

{{{#!sql
SELECT
    v.student_index,
    s.first_name,
    s.last_name,
    v.volunteer_role
FROM volunteers v
JOIN students s
    ON s.student_index = v.student_index
WHERE v.et_name = 'Job Fair'
  AND v.event_title = 'Job Fair 2026'
  AND v.event_start_time = TIMESTAMP '2026-03-23 09:00:00'
  AND v.est_name = 'Company Stands'
  AND v.es_start_time = TIMESTAMP '2026-03-24 10:00:00'
  AND v.location = 'MFS'
ORDER BY s.last_name, s.first_name;
}}}