CI4 $this-db->Table() inside foreach or outside

I have the following code:

PHP Code:

foreach($sales_taxes as $line => $sales_tax)
{
    $builder = $this->db->Table('sales_taxes');
    $builder->insert($sales_tax);
} 


This will reassign the $builder in each iteration of the loop. Is that needed? I don't fully understand how and when the $builder is reset. If I were to call the below code instead would it still run an insert in each iteration?

PHP Code:

$builder = $this->db->Table('sales_taxes');

foreach($sales_taxes as $line => $sales_tax)
{
    $builder->insert($sales_tax);
}