PHP Error : Trying to get property of non-object

[henqi (Hengkhee)]

I don’t understand how this happen (I want to retrieve single sample customer from particular postcode):

00114:     public function GetCustomerName($state) {

00115:         $criteria = new CDbCriteria;

00116:         $criteria->select = 'lastname';

00117:         $criteria->condition = 'postcode=:xx';

00118:         $criteria->params = array(':xx'=>$postcode);

00119:         $criteria->limit = 1;

00120:         $tmpModel = Customer::model()->find($criteria);

00121: 

00122:         return $tmpModel->lastname;

00123:     }

But Yii through PHP Error:

Description

Trying to get property of non-object, at line 122.

I using find() (not findAll) which should only return 1 ActiveRecord object, but when I

print_r($tmpModel, true)

to yii log, found there is an array of Custommer Active Record, sound like the

$criteria->limit

not working… can somebody please advice?

Thanks.

[sluderitz]

You should always check if a model was found before accessing a property:

if($tmpModel) {

    return $tmpModel->lastname;

} else {

    return null;

}

Your function has the parameter $state, the variable you are using later on is called $postcode though, so nothing can be found. Please check.

[henqi (Hengkhee)]

I use Yii DAO to solve this problem.

public function GetCustomerName_DAO($postcode) {

	$command=Yii::app()->db->createCommand(

			"SELECT lastname FROM Customer WHERE postcode=:PARA LIMIT 1");

        $command->bindParam(":PARA", $postcode, PDO::PARAM_INT);

        $dataReader = $command->query();

        $row = $dataReader->read();

        $dataReader->close();


	return $row['lastname'];

}

But I need to understand what is my problem about this…

Thanks.

[henqi (Hengkhee)]

You should always check if a model was found before accessing a property:

if($tmpModel) {

    return $tmpModel->lastname;

} else {

    return null;

}

Your function has the parameter $state, the variable you are using later on is called $postcode though, so nothing can be found. Please check.

Sorry, my typo mistake (this post topic)… the variable passed should be $postcode, not $state.

Yes, you are right, I need to check what was found everytime using ActiveRecord. For this case and my problem is, the array of ActiveRecrord is found, I need to has only 1 ActiveRecord record, not array.

I use only find(), not findAll(), and I set limit=1, but still return array of records…

Am I miss anythings on the code?

[Ismael (Shalanga)]

Use find() to return a object and not findAll() with limit = 1.

Look in the source code and you’ll see that find() internally use limit = 1.

[pestaa]

If you use find() you don’t have to explicitly set criteria limit – that’s done internally as well.

If you share your logs, we could help you more easily. As sluderitz mentioned, you used an unknown variable ($postcode), and passed an unnecessary parameter ($state), this might also cause some headache for the interpreter.

[henqi (Hengkhee)]

Sorry to you all, here is the original code (I typo error in the first post of this title), the $state is non exist, it is actually $postcode.

The find() return 1 object as expected. (my problem in the previous post, course I has a for loop to call this function)

00114:     public function GetCustomerName($postcode) {

00115:         $criteria = new CDbCriteria;

00116:         $criteria->select = 'lastname';

00117:         $criteria->condition = 'postcode=:xx';

00118:         $criteria->params = array(':xx'=>$postcode);

00119:         $criteria->limit = 1;

00120:         $tmpModel = Customer::model()->find($criteria);

00121:         Yii::log(print_r($tmpModels, true), 'info');

00122:         return $tmpModel->lastname;

00123:     }

The log too long, I paste the beginning and end (skip table definition) of the dump:

2009/09/09 10:29:26 [info] [application] Customer Object

(

    [_md:private] => CActiveRecordMetaData Object

        (

            [tableSchema] => CMysqlTableSchema Object

                (

                    [schemaName] =>

                    [name] => Customer

                    [rawName] => `Customer`

                    [primaryKey] => id

                    [sequenceName] =>




        )


    .....

    .....

    ..... 

    .....


    [_new:private] =>

    [_attributes:private] => Array

        (

            [lastname] => Smith

        )


    [_related:private] => Array

        (

        )


    [_c:private] =>

    [_errors:private] => Array

        (

        )


    [_va:private] =>

    [_se:private] =>

    [_e:private] =>

    [_m:private] =>

)

The Customer model is generated by Yii shell, with no additional added variables., just add some private function.

From the log. this is the ActiveRecord object I needed, and I found the data I want: "Smith",

but when I want to access data by

     return $tmpModel->lastname;

Yii show me "Trying to get property of non-object" error… I use DAO by this query

[sql]

"SELECT lastname FROM Customer WHERE postcode='$postcode' LIMIT 1"

[/sql]

then the problem solved… I am sure I am missing something with the ActiveRecord…