How to perform basic DataBase operations with CodeIgniter?

Configuration of the Database

First, you have to configure the Database (DB) in the folder /application/config/database.php. In this file, you will be able to set everything about the database. The main lines you would have to configure are the first five in the following code:

<?php
$db['default'] = array(
1   'dsn'      => 'mysql:host=localhost; dbname=domainname; charset=utf8',//Describe the connection to the DB
2   'hostname' => 'localhost',             //The hostname of your server
3   'username' => 'name',                  //Users who can access to the DB
4   'password' => 'pass',                  //Password required for accessing to the DB
5   'database' => 'dbname',                //Name of the DB
6   'dbdriver' => 'pdo',                   //Driver of the DB
7   'dbprefix' => '',                      //Optionnal, prefix for a table name
8   'pconnect' => FALSE,                   //Whether to use a persistant connection
9   'db_debug' => (ENVIRONMENT !== 'production'),  //How to display errors (environment)
10  'cache_on' => FALSE,                   //Enable/Disable query caching
11  'cachedir' => '',                      //Location of the cache
12  'char_set' => 'utf8',                  //The character set used in communication with the DB
13  'dbcollat' => 'utf8_general_ci',       //The character collation used in communicating with the DB
14  'swap_pre' => '',                      //A default table prefix that can be swapped with the dbprefix
15  'encrypt'  => FALSE,                   //Whether or not to use an encrypted connection
16  'compress' => FALSE,                   //Whether or not to use client compression (MySQL only)
17  'stricton' => FALSE,                   //TRUE/FALSE - forces 'Strict Mode' connections
18  'failover' => array(),                 //An array with data in case the connection to the main db fails
19  'save_queries' => TRUE                 //TRUE/FALSE - Whether to "save" all executed queries.
); 
?>

Connection to the Database

There is two way to make a connection to a database. It can be done manually or automatically.

Automatically, you will load the database in every page of your website. For it, add the word database in the folder : application/config/autoload.php.
Manually, you will load the database in pages where the next line of code will be written
```
$this -> load -> database()
```

How to make queries ?

Every functions you could use to manipulate the database can be founded on this page. To make a summary, I will quote the main functions you could use:

How to find a name, ID, email...

// Select any row where the field title = $title and the field status = $status
$array = array('name' => $name, 'title' => $title, 'status' => $status);
$this->db->where($array);
$query = $this->db->get('mytable');
$result = $query->result_array();

How to insert data

// Insert a new row in the table
$data = array('name' => Paris, 'title' => Amour, 'Date' => 1998);
$this->db->insert('mytable',$data);

How to update data

// Update a given row in the table
$this->db->set('field','field+1');
$this->db->where('id',4);
$this->db->update('mytable');

How to order data

// Order titles in increasing order
$this->db->order_by('title','ASC');
// Order titles in descending order
$this->db->order_by('title','DESC');
// Order titles randomly
$this->db->order_by('title','RANDOM');

How to delete data

// Delete the data where id=$id from the table mytable
$this->db->delete('mytable', array('id'=>$id);
// Delete an entire table
$this->db->empty_table('mytable');

A lot of other functions are available : like(), count_all_results(), select_avg or limit().

How to perform basic DataBase operations with CodeIgniter?

Configuration of the Database

Connection to the Database

How to make queries ?

See also