Hi sir,
I am a chief developer in dahuasoft online support.
I have just read your job description and been excited.
Please check my working history.
I have just done very similar job like your requirements.
Job link: https://www.freelancer.com/projects/PHP-Website-Design/PHP-Assessment-Quiz-Site-with.html
In there , all quiz & answers are sent to relational db as json.
Please open chat to discuss further detail.
Sincerely,
An