How to check a query in CodeIgniter 3.0.3 (delete,update,select,insert)?

Question

I have a project in codeigniter 2.0 and I used:

$query = $this->db->query('select * FROM my_table');

if($query->num_rows()==1) return true; else return false;

But in codeigniter 3.0.3 i don't know how to check (update, select, insert, delete... ).

Answer 1

for insert,update

$this->db->affected_rows(); Displays the number of affected rows, when

doing “write” type queries (insert, update, etc.).

if ( $this->db->affected_rows() > 0 ) 
   {
   return TRUE;
   }
   else 
  {
   return FALSE;
   }

for select

doing “select” type queries (insert, update, etc.).

 if ($query->num_rows() > 0)
    {
       $dataSet = $query->result();
    }

for delete

$res = $this->a_model->delete_product($id); // example delete 

if($res == FALSE)
{
}else
{
}

Answer 2

$query = $this->db->query("SELECT * FROM my_table");
$dataSet = array();
if ($query->num_rows() > 0)
{
   $dataSet = $query->result();
}

print_r($dataSet);

Answer 3

From the Cogidignitor User Guide 3:

For Select:

The number of rows returned by the query. Note: In this example, $query is the variable that the query result object is assigned to:

$query = $this->db->query('SELECT * FROM my_table');
if($query->num_rows() > 0){
    return true;
}
else{
    return false;
}

For UPDATE & INSERT Statements:

$this->db->affected_rows()

Displays the number of affected rows, when doing “write” type queries (insert, update, etc.).

Example:

$this->db->update('UPDATE statement');
$this->db->affected_rows();

$this->db->insert('INSERT statement');
$this->db->affected_rows();

Alternate for INSERT:

You can also use last insert id as like:

$this->db->insert('INSERT statement');
$id = $this->db->insert_id();

if($id > 0){
  return true;
}
else{
 return false; 
}

For Delete:

DELETE always return the true in result if query executed else false, affected_rows will also return same:

$this->db->delete('DELETE statement');

if($this->db->affected_rows()){
  return true;
}
else{
  return false;
}