:projectId and :projectID

One Page 125:

public $fixtures=array( ‘projects’=>‘Project’, ‘users’=>‘User’, ‘projUsrAssign’=>’:tbl_project_user_assignment’, );

It says using ":" to indicate that this is a database table, and not an AR model class. - I understand

On Page 129:

$issueDataProvider=new CActiveDataProvider(‘Issue’, array( ‘criteria’=>array(


‘params’=>array(’:projectId’=>$this->loadModel()->id), ),

There is no explanation why “:” is being used. Could someone please explain this to me? I’m very confused. The only “projectId” variable is found in the filter function of IssueController. I’m not sure if :projectId is referencing that variable.

On Page 144, there is a line:


I’m not sure if this is a typo of :projectId or its another reference to some other places.

The code seems to work fine but I’m very confused.

Please help. Thank you.

To understand the placeholders in a select read this - http://www.php.net/manual/en/pdostatement.bindparam.php

Basicaly :projectid is a placeholder (not a variable) that is replaced with a value that you assign to it with ‘params’

I can understand the link you gave me but still quite confused in the context of the book…

Can you explain what you don’t understand…

As per your question… .you did not understand what is :projectid… and you thouth it’s a variable…

So if you now understand the concept of binding… then you know that on this line


:projectId is just a placeholder… it does not have any value for now… a real value will be binded here…

and this line

'params'=>array(':projectId'=>$this->loadModel()->id), ),

Say that the value of $this->loadModel()->id should be placed instead of the placeholder :projectId

Hope it’s clear now… :)

I see,

However, what would replace the place holder of :projectID ?

this (http://www.php.net/manual/en/pdostatement.bindparam.php) suggests that a variable name same as the place holder will replace it’s value?!

Is that the same in this case?