How to insert multiple data with one form submission [ LARAVEL - Eloquent ] - laravel

Question

I have form where I am planning to insert data into units table .. it has fields course_id | unit_number | unit_title
relationship defined : course has many units .. units belongs to course.
the form is working fine, in case I'm inserting only one unit. but when I insert multiple rows it only stores the last row.
#include('admin.messages')
<form action="{{ route('adminSendCreateUnits')}}" method="post" enctype="multipart/form-data">
{{csrf_field()}}
<div class="row col-12">
<div class="col-sm">
<div class="form-group">
<label style="width:100%; background-color:grey; color:white; padding:15px;" for="course_id">Course</label>
<select name="course_id" class="form-control">
<option>Select Course</option><!--selected by default-->
#foreach ($courses as $course)
<option value="{{$course->id}}">
{{ $course->id}}-{{ $course->crs_title}}
</option>
#endforeach
</select>
</div>
</div>
</div><br>
<label for="unit_number">Unit Number</label>
<select name="unit_number[]" class="form-control">
<option value="1">1</option>
<option value="2">2</option>
<option value="3">3</option>
<option value="4">4</option>
<option value="10">10</option>
</select>
<label for="unit_title">Unit Title</label>
<input type="text" class="form-control" name="unit_title[]" id="unit_title" placeholder="Unit Title" required>
my unitscontroller.php [ I'm sure this is wrong .. since I was trying stuff and i lack the knowledge]
public function adminSendCreateUnit(Request $request){
$course_id = $request->input('course_id');
$unit_number = $request->input('unit_number', []);
$unit_title = $request->input('unit_title', []);
$newCategoryArray = array(
"course_id"=>$course_id,
"unit_number"=>$unit_number,
'created_at' => \Carbon::now(),
"unit_title"=> $unit_title);
$created = DB::table("units")->insert($newCategoryArray);
if($created){
return redirect()->route("adminAllUnits")->withSuccess('Unit Created successfully!');
}else{
return "Unit was not Created";
}
}
I would like to have the course ID same in all rows .. only Unit number and titles change. would appreciate any input :)

Answer 1

Solved by trying this out.
public function adminSendCreateUnit(Request $request){
$course_id = $request->input('course_id');
$unit_number = $request->input('unit_number', []);
$unit_title = $request->input('unit_title', []);
$units = [];
foreach ($unit_number as $index => $unit) {$units[] = [
"course_id" => $course_id, // change this
"unit_number" => $unit_number[$index],
'created_at' => \Carbon::now(),
"unit_title" => $unit_title[$index]
];
}
$created = Unit::insert($units);
if($created){
return redirect()->route("adminAllUnits")->withSuccess('Unit Created successfully!');
}else{
return "Unit was not Created";
}
}