Foreign Key Constraint Issue

$deleted = DB::table('responder_feedback_status')->where('project_id',$id)->delete();

Here’s how to resolve this issue:

### Steps to Fix

1. **Understand the Foreign Key Relationship:**
– The `responder_feedback_status` table references the `responders` table via the `responder_id` foreign key.
– Deleting rows in the `responders` table would violate this constraint if there are still rows in `responder_feedback_status` referencing the `responder_id`.

2. **Ensure Proper Order of Deletion:**
– You need to delete rows from the `responder_feedback_status` table first, where the `responder_id` is linked to the rows you want to delete in the `responders` table.

3. **Update Your Code:**
Modify your code to delete from the `responder_feedback_status` table first, then delete from the `responders` table. Here's an example:

DB::transaction(function () use ($id) {
       // Get all responder IDs linked to the project
       $responderIds = DB::table('responders')
           ->join('participants', 'participants.id', '=', 'responders.participant_id')
           ->where('participants.project_id', $id)
           ->pluck('responders.id');

       // Delete related rows from responder_feedback_status
       DB::table('responder_feedback_status')
           ->whereIn('responder_id', $responderIds)
           ->delete();

       // Delete responders
       DB::table('responders')
           ->join('participants', 'participants.id', '=', 'responders.participant_id')
           ->where('participants.project_id', $id)
           ->delete();
   });

4. **Enable Cascade Delete (Optional):**
If appropriate, you can set up **ON DELETE CASCADE** on the foreign key constraint in your database. This will automatically delete rows in `responder_feedback_status` when a referenced row in `responders` is deleted.

To add cascading delete:

ALTER TABLE responder_feedback_status
   DROP FOREIGN KEY responder_feedback_status_ibfk_3;

   ALTER TABLE responder_feedback_status
   ADD CONSTRAINT responder_feedback_status_ibfk_3
   FOREIGN KEY (responder_id) REFERENCES responders(id)
   ON DELETE CASCADE;

⚠️ Be careful with this approach, as it automatically deletes dependent records and might lead to unintended data loss.

5. **Test Your Changes:**
– Test thoroughly to ensure no unintended deletions or errors occur.

### Why This Happens
Foreign key constraints ensure referential integrity in your database. The `responder_feedback_status` table has a foreign key pointing to `responders`, so MySQL prevents you from deleting a `responder` row that is still being referenced.

By properly ordering the deletions or using cascading deletes, you can resolve this issue.