Summary of optimized writing methods for operating database tables with Codeigniter

Summary of optimized writing methods for operating database tables with Codeigniter_PHP tutorial

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Release： 2016-07-13 10:28:32

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I have been using codeigniter for a while, but I haven’t made any summary yet. Now I will summarize some optimized writing methods for operating database tables in Codeigniter. Although it is not comprehensive, it can indeed help students who are just getting started with CI.

Link database

Copy code The code is as follows:

$this->load->database();//Manually connect to the database
//Connect multiple databases
$DB1 = $this->load->database('group_one', TRUE);
$DB2 = $this->load->database('group_two', TRUE);

Query

Copy code The code is as follows:

//Parameter binding form
$sql = "SELECT * FROM some_table WHERE id = ? AND status = ? AND author = ?";
$this->db->query($sql, array(3, 'live', 'Rick'));

//Multiple Result standard query
$query = $this->db->query($sql); //Customized
$query = $this->db->get('tablename'); //Convenient form, equivalent to: SELECT * FROM tablename
$query = $this->db->get('tablename', 10, 20); // Equivalent to: SELECT * FROM tablename LIMIT 20, 10

$query->result() //Object form
$query->result_array() //Array form
/*
foreach ($query->result () as $row)
{
echo $row->title;
echo $row->name;
echo $row->email;
}
*/
$query->num_rows() //Total number of items
$query->num_fields() //Number of fields

//Single result standard query
$row = $query->row(); //Object form
$row = $query->row_array(); //Array form
/*
$row = $query->row_array ();
echo $row['name'];
*/

Insert

Copy code The code is as follows:

$data = array(
'title' => name' => $name
);
$this->db->insert('tablename', $data); //Convenient insertion of
$this->db-> insert_string('tablename', $data); //Convenient insertion

$this->db->insert_id() //The id just inserted
$this->db-> affected_rows() //Number of affected rows (update,insert)

Update

Copy code The code is as follows: email' => $email );

$where = "id = 1";

$this->db->update('tablename', $data);
$ this->db->update_string('tablename', $data, $where);

Delete

Copy code

The code is as follows:

$array = array(
                'name' => $name,
                'title' => $title
                );
$this->db->delete('tablename', $array);

// Produces:
// "DELETE FROM tablename WHERE name = '$name' AND title = "$title""

$this->db->truncate('tablename'); //清空表
// Produce: TRUNCATE tablename

-----------------------------------------------------
（where）
-------

$array = array(
                'name' => $name,
                'title' => $title
                );
$this->db->where($array);
// Produces: "WHERE name = '$name' AND title = "$title""
-----------------------------------------------------
$this->db->count_all('tablename'); //表中记录总行数
-----------------------------------------------------
$query->free_result() //释放资源