如何获得上一个或下一个ID

Question

Using Jamie Rumbelow's My_Model and mySQL. I am not able to find, how to get a last inserted Id in a particular table. For example,

Table_A

--------+
id      |
--------+
1       |
--------+
2       |
--------+

I am try below code but it returning int(0)

  $id = $this->Model_teacher->_database->insert_id();

Answer 1

I found the library you are using.. https://github.com/jamierumbelow/codeigniter-base-model/blob/master/core/MY_Model.php

public function insert($data, $skip_validation = FALSE)
    {
        if ($skip_validation === FALSE)
        {
            $data = $this->validate($data);
        }
        if ($data !== FALSE)
        {
            $data = $this->trigger('before_create', $data);
            $this->_database->insert($this->_table, $data);
            $insert_id = $this->_database->insert_id();
            $this->trigger('after_create', $insert_id);
            return $insert_id;
        }
        else
        {
            return FALSE;
        }
    }

When an insert is successful, it returns $insert_id;

$id = $this->Model_teacher->insert(...);