navigating an array of objects in javascript

Question

Need help forming javascript objects from MySQL rows of data. I'm using IE9 and Chrome on Windows-7.

I've managed to get what I believe to be an array (of objects) in Javascript from mySQL data. I can use alerts to see the whole array, as well as one individual object, as in my code.

What I cannot do yet is navigate a particular object's properties (the column values of a particular row in the database).

What I need to do is iterate through myObjects, and use the property values in each to create some graphics. I also need to be able to retrieve each object's properties at any time going forward as well.

UPDATE: including my php located in head html object:

    <?php
    //------------------- constants --------------------
    $objects = array();
    $jsonData = "";
    //------------------- database connection ----------
    $data_source = 'mysql:host=localhost;dbname=myDB';
    $db_user = 'root';
    $db_password = 'password';
    $conn = new PDO($data_source, $db_user, $db_password,
              array(PDO::ATTR_EMULATE_PREPARES => false,
                    PDO::ATTR_ERRMODE => PDO::ERRMODE_EXCEPTION,
                    PDO::ATTR_PERSISTENT));
    //prepare query
    $stmt = $conn->prepare("SELECT * FROM tblbranchstatus");
    $stmt->execute();
    //fetch each row of results
    while($row = $stmt->fetch(PDO::FETCH_ASSOC)) {
      $rows[] = json_encode($row);
    }
?>

var ART = {};
//capture data from database as json string data
ART.strJSON = <? php echo json_encode($rows); ?> ;
//capture json string data as array of javascript objects
//using 'eval' cause I know this data's source and I couldn't get JSON.parse to work
ART.myObjects = eval(ART.strJSON);
ART.branch = ART.myObjects[6];
alert(ART.branch); // this gives me the expected object {"a":"aa", "b":"bb"...}
alert(ART.branch.a); // can't retrieve the property - gives me 'undefined'

Answer 1

This doesn't look like the right thing to do. Here's what you should be doing:

while($row = $stmt->fetch(PDO::FETCH_ASSOC)) {
      $rows[] = $row;
}

Don't do json_encode() on each row.

ART.myObjects = <?php echo json_encode($rows); ?>;

You can immediately use the output of json_encode($rows) in your script.

Update

As rightfully mentioned by bfavaretto, you can make this even shorter by encoding all rows in one go:

ART.myObjects = <?php echo json_encode($stmt->fetchAll(PDO::FETCH_ASSOC)); ?>;

Answer 2

I would check if ART.branch is actually a string with the JSON notation rather than the actual object.