Convert from date to epoch-Oracle

Question

I need to convert a date from a TextBox from date to epoch time so that I can insert it into Oracle DB.

I managed to convert from epoch to date as below, but couldn\

Answer 1

UpdateCommand="UPDATE CONTRACTORS
                                           SET COMPANY=:COMPANY,
                                               FIRST_NAME=:FIRST_NAME,
                                               LAST_NAME=:LAST_NAME,
                                               ID_NUMBER=:ID_NUMBER,
                                               TRAINING_DATE=(TO_DATE(:TRAINING_DATE, 'MM-DD-YYYY HH24:MI:SS') - TO_DATE('01-JAN-1970','DD/MM/YYYY'))*24*60*60,
                                               TRAINING_VALABILITY=(TO_DATE(:TRAINING_VALABILITY, 'MM-DD-YY`enter code here`YY HH24:MI:SS') - TO_DATE('01-JAN-1970','DD/MM/YYYY'))*24*60*60
                                           WHERE (ID=:ID)"

Answer 2

Subtracting DATE '1970-01-01' from the value will give the number of days (and fractional hours/minutes/seconds) difference and then you can multiply by 24*60*60:

(date_value - DATE '1970-01-01')*24*60*60

---

Update:

Typically, epoch time is measured from 1970-01-01T00:00:00 UTC. If your date is not in UTC then you will need to convert time zones.

For example, if your date has the time zone Europe/Berlin:

( CAST(
    FROM_TZ(
      CAST( date_value AS TIMESTAMP ),     -- Cast to timestamp
      'Europe/Berlin'                      -- Convert to expected Time Zone
    )
    AT TIME ZONE 'UTC'                     -- Convert Time Zone to UTC
    AS DATE                                -- Cast back to DATE data type
  )
  - DATE '1970-01-01'
)*24*60*60

db<>fiddle