app.js

var JDBMS = angular.module('JDBMS',[]);

JDBMS.controller('MainCtrl',function($scope, $http){
	$http.get('database.json').success(function(data) {
    $scope.data = data;

    $scope.tupleToInsert;
    $scope.tupletoUpdate;
    $scope.attrIndex;
    $scope.updateValue;
    $scope.oldValue;
  	});
	$scope.displayTable = function(table){
		$scope.selectedTable = table;
	}

	$scope.shouldDisplay = function(row){
		var obj = JSON.parse($scope.constraintText);
		var retval = true;
		for (var i = obj.length - 1; i >= 0; i--) {
			if(obj[i][1] === 'equals'){
				if(!(row[obj[i][0]] === obj[i][2]))
					retval = false;				
			}
			else if(obj[i][1] === 'greater'){
				if(!(row[obj[i][0]] > obj[i][2]))
					retval = false;				
			}
			else{
				if(!(row[obj[i][0]] < obj[i][2]))
					retval = false;				
			}		
		}
		return retval;
		
	}
	$scope.applyConstraint = function(constraint){
		$scope.constraintText = constraint;
	}
	$scope.insertTuple = function(){
		var obj = JSON.parse($scope.tupleToInsert);
		$scope.selectedTable.data.push(obj);
		console.log($scope.selectedTable);
	}

	$scope.addTable = function(){
		var queryFinal = '{'+$scope.tableQuery+',"data": []}';
		//console.log(queryFinal);
		var obj = JSON.parse(queryFinal);
		$scope.data.push(obj);
		$scope.tableQuery='';
	}

	$scope.dropTable = function(){
		var tableName = $scope.selectedTable.name;
		for (var i = $scope.data.length - 1; i >= 0; i--) {
			if($scope.data[i] == $scope.selectedTable)
				break;
		}
		$scope.data.splice(i, 1);
		var i, j;
		for (i = $scope.data.length - 1; i >= 0; i--) {
			for (j = $scope.data[i].schema.length - 1; j >= 0; j--) {
				if($scope.data[i].schema[j].hasOwnProperty('foreign_key') && $scope.data[i].schema[j].foreign_key === tableName)
					break;
			}
			if(j >= 0){
				$scope.data[i].schema.splice(j, 1);
				for (var k = 0; k < $scope.data[i].data.length; k++) {
					$scope.data[i].data[k].splice(j, 1);	
				}
			}			
		}
		$scope.selectedTable = '';
	}
	$scope.setUpdateField = function(tuple,col_no){
		$scope.tupletoUpdate = tuple;
		$scope.attrIndex = col_no;
	}
	$scope.getPrimaryKeyIndex = function(table){//return table.primary_key;
		for(var i=0;i<table.schema.length;i++)
		{
			if(table.schema[i].field === table.primary_key)
			{
				return i;
			}
		};
	}
	$scope.updateOtherTables = function(operation){
		
		for(var i=0;i<$scope.data.length;i++)
			{
				for(var j=0; j<$scope.data[i].schema.length; j++)
				{
					if($scope.data[i].schema[j].hasOwnProperty('foreign_key') && $scope.data[i].schema[j].foreign_key === $scope.selectedTable.name)
					{

						for(var k=$scope.data[i].data.length-1;k>=0;k--)
						{
							if($scope.data[i].data[k][j] === $scope.oldValue)
							{
								if(operation == "update")
								{
								$scope.data[i].data[k][j] = $scope.updateValue;
								}
								else
								{
									$scope.data[i].data.splice(k,1);
								}
							}
						}
					}
				}
			}
		
	}
	$scope.update = function(){
		$scope.oldValue = $scope.tupletoUpdate[$scope.attrIndex];
		$scope.tupletoUpdate[$scope.attrIndex] = $scope.updateValue;
		if($scope.getPrimaryKeyIndex($scope.selectedTable) == $scope.attrIndex)
		{
			$scope.updateOtherTables("update");	
		}
	}
	$scope.deleteTuples = function(index){
		$scope.oldValue = $scope.selectedTable.data[index][$scope.getPrimaryKeyIndex($scope.selectedTable)];
		$scope.selectedTable.data.splice(index,1);
		$scope.updateOtherTables("delete");
	}
});