PHP Transaction-like sql required?
I used cURL to authenticate first then login via POST to a cms.

Then another POST again to ask the cms to generate a new code number (eg voucher code) and grab the csv from url that contain about 70 lines per page.

I can explode each line and get the last line for the new code number that is generated before.

My question is if many requests are created by many customers, is it possible to accidentally reading the same voucher code? Although cURL get the csv file pretty fast, should I make sure that a request must be completed first before another? like a sql transaction.

Though I read somewhere php do not run in parallel, since I am a beginner in all these and someone asked me if my script can cause that for multiple requests. THanks in advance.
PHP Transaction-like sql required?
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I used cURL to authenticate first then login via POST to a cms.

Then another POST again to ask the cms to generate a new code number (eg voucher code) and grab the csv from url that contain about 70 lines per page.

I can explode each line and get the last line for the new code number that is generated before.

My question is if many requests are created by many customers, is it possible to accidentally reading the same voucher code? Although cURL get the csv file pretty fast, should I make sure that a request must be completed first before another? like a sql transaction.

Though I read somewhere php do not run in parallel, since I am a beginner in all these and someone asked me if my script can cause that for multiple requests. THanks in advance.