Invalid json string for line chart

soumya reubro

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Aug 14, 2013, 5:53:54 AM8/14/13

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Hi,

I am trying to draw a line chart using Google chart in which data is retrieved from mysql table.But i get the error as follows

Error: Invalid JSON string: {"cols":[{"label":"id","type":"string"},{"label":"date","type":"string"}],"rows":["1","2013-08-13 00:00:00"]}{"cols":[{"label":"id","type":"string"},{"label":"date","type":"string"}],"rows":["2","2013-08-13 00:00:00"]}

the json encoded data looks as follows

{"cols":[{"label":"id","type":"string"},{"label":"date","type":"string"}],"rows":["1","2013-08-13 00:00:00"]}{"cols":[{"label":"id","type":"string"},{"label":"date","type":"string"}],"rows":["2","2013-08-13 00:00:00"]}

Here is the code which i used for line chart developement

<html>

<head>

google.load("visualization", "1", {packages:["corechart"]});

google.setOnLoadCallback(drawChart);

function drawChart() {

var jsonData = $.ajax({

url: "graph1.php",

dataType:"json",

async: false

}).responseText;

var data = new google.visualization.DataTable(jsonData);

var chart = new google.visualization.LineChart(document.getElementById('chart_div'));

chart.draw(data, {width: 400, height: 240});

}

</script>

</head>

<body>

</body>

</html>

PHP part:

$sql = mysql_query("SELECT * FROM `da_insulin_details` LIMIT 0,2 ");

$rows['cols'] = array( array('label' => 'id', 'type' => 'string'),

array('label' => 'date', 'type' => 'string'));

while($row = mysql_fetch_array($sql))

{

$rows['rows'] [0] = $row['id'];

$rows['rows'][1] = $row['date'];

$jsonTable = json_encode($rows);

echo $jsonTable;

}

I am new to this section..anybody pls help me to solve the issue

asgallant

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Aug 15, 2013, 12:10:37 AM8/15/13

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You have the JSON formatted incorrectly. It should represent 1 object with "cols" and "rows" properties. "cols" is an array of objects with "type" (string, mandatory), "label" (string, optional), "id" (string, optional), and "p" (object, optional) parameters. Rows is an array of objects with "c" (array, mandatory), and "p" (object, optional) parameters. The "c" parameter of a row object is an array of objects with "v" (string/number, mandatory), "f" (string, optional), and "p" (object, optional) parameters.

Your columns construction is correct, but you only need it once. Your rows construction needs some work. Let's start with this row:

["1","2013-08-13 00:00:00"]

should be:

{"c":[{"v":"1"},{"v":"2013-08-13 00:00:00"}]}

and this row:

["2","2013-08-13 00:00:00"]

should be:

{"c":[{"v":"2"},{"v":"2013-08-13 00:00:00"}]}

Add them to your "rows" array like this:

"rows":[{"c":[{"v":"1"},{"v":"2013-08-13 00:00:00"}]},{"c":[{"v":"2"},{"v":"2013-08-13 00:00:00"}]}]

You can then combine the whole thing together to make the JSON string:

{"cols":[{"label":"id","type":"string"},{"label":"date","type":"string"}],"rows":[{"c":[{"v":"1"},{"v":"2013-08-13 00:00:00"}]},{"c":[{"v":"2"},{"v":"2013-08-13 00:00:00"}]}]}

soumya reubro

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Aug 15, 2013, 11:51:00 PM8/15/13

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Hi,

Thanx alot for your feedback..will do it as per your suggestion..

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