Vaild JSON, still: DataTables warning: Added data does not match known number of columns

michael.griffith

Hi,

I am using Struts2 as an action to load a DataTable, and getting the DataTables warning: Added data does not match known number of columns. I verified the JSON is valid with a JSON validator. The table looks like this:

[code]



Age
Breed
Gender
Id
Name








[/code]

The jQuery init looks like this:
[code]

$(document).ready(function() {
$('#list_table').dataTable( {
"aoColumns": [null, null, null, null, null],
"bFilter": true,
"bProcessing": true,
"sAjaxSource": './list-data.do'
} );

});

[/code]

And my JSON result looks like this:
[code]
{"aaData":[{"age":0,"breed":"Unkown","gender":"Female","id":0,"name":"Snowflake 0"},{"age":1,"breed":"Persian","gender":"Male","id":1,"name":"Snowflake 1"},{"age":2,"breed":"Unkown","gender":"Female","id":2,"name":"Snowflake 2"},{"age":3,"breed":"Persian","gender":"Male","id":3,"name":"Snowflake 3"},{"age":4,"breed":"Unkown","gender":"Female","id":4,"name":"Snowflake 4"},{"age":5,"breed":"Persian","gender":"Male","id":5,"name":"Snowflake 5"},{"age":6,"breed":"Unkown","gender":"Female","id":6,"name":"Snowflake 6"},{"age":7,"breed":"Persian","gender":"Male","id":7,"name":"Snowflake 7"},{"age":8,"breed":"Unkown","gender":"Female","id":8,"name":"Snowflake 8"},{"age":9,"breed":"Persian","gender":"Male","id":9,"name":"Snowflake 9"},{"age":10,"breed":"Unkown","gender":"Female","id":10,"name":"Snowflake 10"},{"age":11,"breed":"Persian","gender":"Male","id":11,"name":"Snowflake 95"},{"age":96,"breed":"Unkown","gender":"Female","id":96,"name":"Snowflake 96"},{"age":97,"breed":"Persian","gender":"Male","id":97,"name":"Snowflake 97"},{"age":98,"breed":"Unkown","gender":"Female","id":98,"name":"Snowflake 98"},{"age":99,"breed":"Persian","gender":"Male","id":99,"name":"Snowflake 99"}]}
[/code]

What am I doing wrong? Thanks in advance for any reply.

ab

Hey michael,

It seems that you have one extra column in your table header. If you delete the line:
[code][/code]
your issue should go away.

(Also, if you have all the options in aoColumns as null, you don't even need to have it there, although it might make sense to move the width options there from your html).

- ab

michael.griffith

Thanks for the reply ab. The extra I added thinking that I was a column short -- even though the JSON data showed 5 columns. The issue actually appears without the extra table header column, it was an attempt to see if I could force some other error than the one that I was getting. Thanks for the tip on the aoColumns issue.

Does any other problem jump out with the JSON response? Is the problem possibly with the leading and trailing

[code]{"aaData"[...]} [/code]

Object definition?

allan

ab is exactly right - you need aoColumns, the length of the inner Arrays in aaData and the HTML columns all to match. However, even with that addressed (as per your post) the JSON format you've got isn't one that DataTables supports. DataTables expects and array of arrays, not an array of objects for aaData. You need something like:

[code]
aaData: [
[ 1, 2, 3 ],
[ 4, 5, 6 ]
]
[/code]
The reason for this is that you would need to tell DataTables what column 'id' (etc) belong to. It's possible and probably fairly easy in the code to hack that in - but adds a little more complexity. So I'd suggest if you can change the server-side code to just give you a 2D array that will do nicely - if that can't be done, you could use fnServerData to convert the array of objects in a 2D array.

Allan