CodeIgniter - ci_sessions migrations - php

Question

I was wondering if someone can help out.
Im just getting into using migrations with CodeIgniter, but im having trouble trying to figure out how to convert SQL to the migrations.
Is there anyone out there that could convert this SQL to migrations for me so i can see how its done.
The SQL i have is as follows:
CREATE TABLE IF NOT EXISTS `ci_sessions` (
`session_id` varchar(40) COLLATE utf8_bin NOT NULL DEFAULT '0',
`ip_address` varchar(16) COLLATE utf8_bin NOT NULL DEFAULT '0',
`user_agent` varchar(150) COLLATE utf8_bin NOT NULL,
`last_activity` int(10) unsigned NOT NULL DEFAULT '0',
`user_data` text COLLATE utf8_bin NOT NULL,
PRIMARY KEY (`session_id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8 COLLATE=utf8_bin;

Answer 1

Please read the documentation here:
CodeIgniter Migrations
In essence, you will want to use the CodeIgniter dbforge class to create the table. Using your code above:
$this->dbforge->add_field(array(
'session_id' => array(
'type' => 'VARCHAR',
'constraint' => '40'
),
'ip_address' => array(
'type' => 'VARCHAR',
'constraint' => '16'
),
'user_agent' => array(
'type' => 'VARCHAR',
'constraint' => '150'
),
'last_activity' => array(
'type' => 'INT',
'constraint' => '10'
),
'user_data' => array(
'type' => 'TEXT'
)
));
$this->dbforge->add_key('session_id', TRUE);
$this->dbforge->create_table('ci_sessions');
Documentation on dbforge class can be found here:
ellislab.com/codeigniter/user-guide/database/forge.html
Note: I don't recommend messing with the CI Sessions table, though.

Answer 2

You can also simply do this if you've a block of large SQL query you know is "safe" and you want to save time (in my opinion it's a judgement call based on the complexity of the table and the chance of making an error when translating the raw SQL into arrays - after all in migrations everything is hardcoded and you're not worrying about the chances of SQL injection etc.)
$sql = "CREATE TABLE IF NOT EXISTS `ci_sessions` (
session_id varchar(40) DEFAULT '0' NOT NULL,
ip_address varchar(45) DEFAULT '0' NOT NULL,
user_agent varchar(120) NOT NULL,
last_activity int(10) unsigned DEFAULT 0 NOT NULL,
user_data text NOT NULL,
PRIMARY KEY (session_id),
KEY `last_activity_idx` (`last_activity`)
)";
$this->db->query($sql);
However I don't think I'd recommend loading the sessions table as a migration, because if $config['sess_use_database'] in config/config.php is true, when you go to your migration URL it'll fail, as Codeigniter will first try to create a session entry in the database for your browser and the database table doesn't yet exist..
A Database Error Occurred
Error Number: 1146
Table 'characterhub.ci_sessions' doesn't exist
So for it to work, you or whomever is performing the migration has to set sess_use_database to false first, then run the migration, then change it back to true again.