Database class object

Question

I've seen people use this piece of code and I'm trying to understand what it does because I don't see it in any of the codeigniter documenation or in the source code for the database class.

$this->db->ar_orderby

From what my noobnes tells me, $this is a special variable meant to refere a class and the -> means sort of get/use in this case, I would presume db is actually a variable to hold database resource and as a variable was declared as $db but if you are using $this-> you can't use the $ sign... I started learning OOP just about yesterday, and that is all that I know :) — samayo
– samayo, Commented Jan 30, 2013 at 20:13
db is probably instantiated in the constructor. $this->db would get you that db instance within any functions in that class. — aziz punjani
– aziz punjani, Commented Jan 30, 2013 at 20:15
After some searching, I'm fairly convinced that ar_orderby() is a deprecated function. You should use $this->db->order_by(); — Jeff
– Jeff, Commented Jan 30, 2013 at 20:19

user20232359723568423357842364 · Accepted Answer · 2013-01-30 20:21:10Z

8

This is an array that holds order by columns..

There should be no reason to use this property directly. Instead call $this->db->order_by('column') which appends to the array automatically.

defined in system/database/DB_active_rec.php Line 42
appended to in method CI_DB_active_record::order_by Line 856
used to generate SQL in CI_DB_active_record::_compile_select Line 1781

answered Jan 30, 2013 at 20:21

user20232359723568423357842364

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Steven · Accepted Answer · 2013-01-30 20:12:44Z

3

You mean

http://phpxref.com/xref/codeigniter/system/drivers/DB_active_record.php.source.html#l781

It allows you to specify the order by.

answered Jan 30, 2013 at 20:12

Steven

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Mukus · Accepted Answer · 2013-12-23 06:32:58Z

3

It still makes sense to use this in the way below -

if (!count($this->db->ar_orderby)) {
    $this->db->order_by($this->order_by );
}

It basically means - If an order is not already set by db library when this method was called, use this. Prevents calling of "order by" twice.

answered Dec 23, 2013 at 6:32

Mukus

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Waqar Ul Hassan · Accepted Answer · 2016-04-20 19:19:02Z

0

You can replace these lines:

if (!count($this->db->ar_orderby)) {
    $this->db->order_by($this->order_by );
}

with:

if(!count($this->db->order_by($this->order_by))) {
    $this->db->order_by($this->order_by);
}

answered Apr 20, 2016 at 19:19

Waqar Ul Hassan

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