How to insert corporate details into database

Insert creates a new database record, update will update an existing record.

Delete will delete the record, replace will delete the record then insert it.

PHP Code:

$data = [
        'title' => 'My title',
        'name'  => 'My Name',
        'date'  => 'My date'
];

$builder->replace($data);

// Executes: REPLACE INTO mytable (title, name, date) VALUES ('My title', 'My name', 'My date') 


OK, I understand that. I dont think replace is appropriate.

The only one I need to use is "update" but I cant get it to work.

I want to get the contents of $product placed into the temp_1 field of an existing record. I dont want the other fields of that record interfered with.

If there is existing content within temp_1 then I want it to be overwritten. Currently, because Im dealing with a new field temp_1 is empty.

And currently, Im entering into tbl_members, and later when Ive learnt how, I will do the same in tbl_corporate that Ive recently created.

I have this in the Controller;

PHP Code:

$lcuser = $this->session->userdata('user_name');
$product = $this->input->post('pro');
$this->username_model->update_product($product); 


And this in the Model;

PHP Code:

public function update_product($product)
{
$this->db->where('user_name', $lcuser);
$data = array('temp_1'=> $product);
$this->db->update('tbl_members', $data);
} 


Everything else works except the entry into temp_1.