Update data with new angular data

Question

I have a datatable with some questions and answers. When the page is loaded, "aviation.json" is placed in a datatable. After choosing a different value in the combobox, the data in the datatable needs to be updated. But this does not work, does anyone know what I am doing wrong?

HTML

      Select a category:   

<table ng-table="tableParams" show-filter="true" class="table ng-table-rowselected" id="questionsTable">
    <tr ng-repeat="user in $data"
        ng-click="user.$selected = !user.$selected; changeSelection(user)"
        ng-class="{'active': user.$selected}">
        <td data-title="'Category'" sortable="'Category'" filter="{ 'Category': 'text' }">
            {{user.Category}}
        </td>
        <td data-title="'Question'" sortable="'Question'" filter="{ 'Question': 'text' }">
            {{user.Question}}
        </td>
    </tr>
</table>

The code

$ scope. $ watch ('comboCat', function () {console.log ($ scope.comboCat.name);

    switch ($scope.comboCat.name){
        case "Aviation": console.log("aviaton selected");
            $http.get('aviation.json').success(function(data){
                $scope.data = data;
                console.log("get json aviaton");
            });
            break;
        case "Customer care": console.log("customer care selected");
            //$scope.data = $http.get('customerCare.json');
            $http.get('customerCare.json').success(function(data){
                $scope.data = data;
            });
            break;
        case "Finance": console.log("Finance selected");
            $http.get('finance.json').success(function(data){
                $scope.data = data;
            });
            break;
    }
});