Insert data into two tables, one depend on another - codeigniter

Question

For example I have such structure in database:
table1:
[id]
[content]
table2:
[id]
[table1_id]
and I want insert some data at the same time into this two tables, but the problem is with [table1_id] which is primary key from table1. How can I insert it?

Answer 1

In order to insert the primary key of table 1 into table 2, code igniter has built in helper functions to help with this task.
//prepare data for table 1
$data = array(
'conent' => 'My content',
);
//insert into table 1
$this->db->insert('table1',$data);
//prepare data for table 2
$data = array(
'table1_id' => $this->db->insert_id(),
);
//insert into table 2
$this->db->insert('table2',$data);

Answer 2

As you are referring table1_id in table2 so u must insert your table1 fields first. Then you can insert into table2.
Here is what you can do in your controller
public function insert(){
$data['table1_data']=$this->ur_model->insert_table1();
$latest_id=$this->ur_model->get_latest_id();
$data['table1_data']=$this->ur_model->insert_table2($latest_id);
}
in your model
function insert_table1(){
$data=array(
'content'=>$this->input->post('content')
);
$this->db->insert('table1',$data);
//better return true on success
}
public function get_latest_id(){
$sql=$this->db->query("SELECT MAX(id) as id FROM table1");
return $sql->row_array();
}
function insert_table2($table1_id){
$data=array(
'content'=>$this->input->post('content'),
'table1_id'=>$table1_id['id']
);
$this->db->insert('table2',$data);
}
So that you will always get latest id inserted into table1_id.