Updating MySQL trigger with additional Query and Insertion Logic - mysql

Question

I have two tables in a MySQL 5.7.28 database. One table with submitted XML data from a form dumped into a single column called xmlData
The second is a table with serves as a datasource for a Datatables based JS site, called Employees
When the xml data is first submitted to the xmlData table, I use the MySQL trigger below to parse and insert the data into Employees.
use test;
DELIMITER $$
DROP TRIGGER IF EXISTS test.Update_xmlData$$
CREATE TRIGGER test.Update_xmlData AFTER INSERT ON xmlData
FOR EACH ROW BEGIN
replace INTO employees (first_name, last_name, startTime, endtime, date)
select ExtractValue(xmlData, '/Data/Employee/first_name') as first_name,
ExtractValue(xmlData, '/Data/Employee/last_name') as last_name,
ExtractValue(xmlData, '/Data/Employee/StartTime') as startTime,
ExtractValue(xmlData, '/Data/Employee/EndTime') as endtime,
ExtractValue(xmlData, '/Data/Employee/date') as date
from xmlData;
END
The output of which looks like this
---------------------------------------------------------------------
first_name | last_name | startTime | endTime | Date
---------------------------------------------------------------------
Luke | Skywalker | 08:00 | 15:00 | 2019-12-05
----------------------------------------------------------------------
Santa | Clause | 08:00 | 14:00 | 2019-12-25
----------------------------------------------------------------------
This trigger works fine and inserts the data properly. The complication is that there maybe multiple start and endtimes in the submitted xmlData row. One set for each day of the week.
For the time being, I'd like to query the submitted XML and persist these values in the Employees table as separate rows. For example, if there are Monday, Tuesday and Wednesday start/end times
the inserted data would look like this:
---------------------------------------------------------------------
first_name | last_name | startTime | endTime | Date
---------------------------------------------------------------------
Luke | Skywalker | 08:00 | 15:00 | 2019-12-05
----------------------------------------------------------------------
Luke | Skywalker | 09:00 | 17:45 | 2019-12-06
----------------------------------------------------------------------
Luke | Skywalker | 06:00 | 18:00 | 2019-12-07
----------------------------------------------------------------------
Santa | Clause | 08:00 | 15:00 | 2019-12-25
----------------------------------------------------------------------
What would be the best approach for updating the trigger to insert new rows IF there are existing StartTime/EndTime for additional days of the week? Is 1 trigger even still viable at this point?
In plain English, I was thinking something along the lines of :
IF TuesdayStartTime and TuesdayEndTime EXISTS THEN insert into Employees another row retaining the same name field values, increment date by 1 day,
IF WednesdayStartTime and WednesdayEndTime EXISTS THEN insert into EMployees another row retaining the same name field values and increment date by 2 days
Submitted XML that is being queried and inserted into employees table:
XML Sample Source Schwartz 08:00 09:00 11:0018:0020191221051312

Answer 1

As Barmar described I can create a loop.
I also found a less elegant way that works by extracting the submitted date and using multiple triggers for each day of the week:
DATE_ADD(ExtractValue(xmlData, '/Data/Employee/date'), interval 1 Day) as date for trigger_Monday
DATE_ADD(ExtractValue(xmlData, '/Data/Employee/date'), interval 2 Day) as date for trigger_Tuesday
Creating an Index of type Unique on the Employees table prevents duplicates.