d3从mysql数据库导入数据返回“未定义”

Question

I'm making a map and I have a huge dataset (almost 4 million record) so I stored it in a mysql database and I query it only for the data I really need to make the map.
I have a pend.php file that return the data in json format and I want to use it in d3

d3.json("data/pend.php", function(error, data) {
  console.log(data);
})

But I only get "undefined".
If I run pend.php directly in the browser I get the json correctly formatted. Here the pend.php code:

<?php
$con=mysqli_connect('localhost', 'root', 'root', 'commuting');
if (mysqli_connect_errno())
  {
  echo "Failed to connect to MySQL: " . mysqli_connect_error();
  }

$result = mysqli_query($con, "SELECT ComResId,ComLavId,NumSum
FROM itaSmall"); 

$number = mysqli_num_rows($result);
$i = 1;
echo "["; 
while($row=mysqli_fetch_array($result))  
    {  
        echo "{'id':'" . $row['ComResId'] . "','des'" . $row['ComLavId'] . "','n':'" . $row['NumSum'] . "'}";  
        if ($i < $number)
           {
               echo ',';
           }
        $i ++;
    }  
echo "]"; 

mysqli_close($con);
?>

And a sample of the outputed json:

[{'id':'1001','des':'1001','n':'469'},{'id':'1001','des':'1004','n':'1'},...

Any idea on what is going wrong?
thanks
daniele

Answer 1

I think that the parameter "error" it's invalid in that function, try with:

d3.json("data/pend.php", function(data) {
  console.log(data);
})

And if you need to get the error function try that:

d3.json("data/pend.php", function(data) {
   console.log(data);
}).fail(function() {
   console.log( "error" );
})

OR:

d3.json("data/pend.php", function(data) {
    console.log(data);
}).error(function() {
    console.log( "error" );
})

Answer 2

Solved....
I was using single quote (instead of dubble quote) to wrap string inside the json!!!