ajax save in database without having foreign key - php

Question

I have a form for users to sign up. This form has a file input which will upload images in a directory in server by ajax instantly as user selects a file. There's also a button which will submit the form and saves user info in user table in database.
Each user can have multiple images. Ajax also save address of images in photos table when file uploads. this table has user_id column. but since the user_id will be generated when submit button is hit and user is not registered yet, I can't fill user_id column in photos table. The id of user is generated when whole form is submitted.
so should I update photos table when form submits by adding id of user to user_id column?
or I must save photos with ajax in temporary_photos table and then when submit is hit save them in main photos table and delete them from temporary table?
or is there another approach?
what if user uploads files, but closes the window without hitting submit button? how I find out the window is close and registration is canceled so i will delete images?

Answer 1

You are trying to solve a problem that you created. If user_id is a dependency for the photo to be saved, let the user be saved first.If you do it the other way , it you will over complicate the workflow.
So, i suggest you register the user first, save the user id in session (or log the user in) and then upload the photo.
If you must do it together, then let the ajax request register the user and then save the photo and save the user_id in a session variable. Next time you upload a photo you could get the user from session variable and save the photo.
function savePhoto(Request $input){
if(Session::has('user_id'){
$user = User::find(Session::get('user_id'));
}
else{
$user = User::create($input->all());
}
$user->photo->save($input->all());
}

Answer 2

You can try this way-
Since an user can have multiple images that means the relation is one to many between. So better if you use a images table.
Table: Images
Column(s): id, user_id, image, uploaded_at
Make user_id field is nullable and image column will save the name of uploaded images. Upon successful uploading and adding iamges record to database save last inserted ids in a session array. Once the user submit the form, create a record to user table, grab the last insert it, check if there are any data in session array, if found, loop through the array and select those images record by id and update user_id field. This will solve your problem.
You also asked for a way to delete images for which users didn't submit the form. To do this, you can run a cronjob/laravel task schedular. A script that will remove images and delete records for those images which were uploaded 5 mins (for example) ago and user_id is still null.