DC.js – Data Table


DC.js – Data Table

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Data table is used to display the records in a tabular format. It lists out the crossfilter dataset records as explained in this chapter in detail.

Data Table Methods

Before moving on to draw a data table, we should understand the dc.dataTable class and its methods. It uses a mixin to get the basic functionality of drawing a data table chart, which is defined below −

  • dc.baseMixin

The dc.dataTable gets all the methods of this mixin and has its own methods to draw the data table, which are explained as follows.

beginSlice( [slice])

This method is used to get or set the index of the beginning slice. This method is useful when implementing pagination.

Similarly, you can perform the endSlice() function as well.

columns( [columns])

This method is used to get or set the column functions. It uses the following method to specify the columns to display.

chart.columns([
   function(d) { return d.mark; },
   function(d) { return d.low; },
   function(d) { return d.high; },
   function(d) { return numberFormat(d.high - d.low); },
   function(d) { return d.volume; }
]);

Here, d represents a row in the data set. We can use HTML to display columns in the data table.

group(groupFunction)

This method is used to perform the group function for the data table.

order( [order])

It is used to sort the order function. If the order is ascending, then the dimension() will use .bottom() to fetch the data, otherwise it will use dimension().top().

Data Table Example

Let us make a data table in DC. To do this, we need to follow the steps given below −

Step 1: Add styles

Let us add styles in the CSS using the coding given below −

.dc-chart { font-size: 12px; }
.dc-table-group { padding-left: 10px; font-size: 14px; font-weight: bold; }
.dc-table-column { padding-left: 10px; font-size: 12px; font-weight: normal; }

Here, we have assigned styles for the chart, table-group and the grid-column.

Step 2: Create a variable

Let us create a variable in DC as shown below −

var barChart = dc.barChart(''#line''); // 
var countChart = dc.dataCount("#mystats");
var tableChart = dc.dataTable("#mytable");

Here, we have assigned a barChart variable id in line, countChart id is mystats and the tableChart id is mytable.

Step 3: Read the data

Read the data from the people.csv file as shown below −

d3.csv("data/people.csv", function(errors, people) {
   var mycrossfilter = crossfilter(people);
}

If the data is not present, then it returns an error. Now, assign the data to a crossfilter. Here, we have used the same people.csv file, which was used in our previous charting examples.

It looks like as follows −

id,name,gender,DOB,MaritalStatus,CreditCardType
1,Damaris,Female,1973-02-18,false,visa-electron
2,Barbe,Female,1969-04-10,true,americanexpress
3,Belia,Female,1960-04-16,false,maestro
4,Leoline,Female,1995-01-19,true,bankcard
5,Valentine,Female,1992-04-16,false,
6,Rosanne,Female,1985-01-05,true,bankcard
7,Shalna,Female,1956-11-01,false,jcb
8,Mordy,Male,1990-03-27,true,china-unionpay

..........................................
..........................................

Step 4: Set the dimension

You can set the dimension using the coding given below −

var ageDimension = mycrossfilter.dimension(function(data) { 
   return ~~((Date.now() - new Date(data.DOB)) / (31557600000)) 
});

After the dimension has been assigned, group the age using the coding given below −

var ageGroup = ageDimension.group().reduceCount();

Step 5: Generate a chart

Now, generate a bar chart using the coding given below −

barChart
   .width(400)
   .height(200)
   .x(d3.scale.linear().domain([15,70]))
   .yAxisLabel("Count")
   .xAxisLabel("Age")
   .elasticY(true)
   .elasticX(true)
   .dimension(ageDimension)
   .group(ageGroup);

Here,

  • We have assigned the chart width as 400 and height as 200.
  • Next, we have specified the domain range as [15,70].
  • We have set the x-axis label as age and y-axis label as count.
  • We have specified the elasticY and X function as true.

Step 6: Create the data table

Now, create the data table using the coding given below −

countChart
   .dimension(mycrossfilter)
   .group(mycrossfilter.groupAll());

tableChart
   .dimension(ageDimension)
   .group(function (data) {
      return ~~((Date.now() - new Date(data.DOB)) / (31557600000));
   })

Here, we have specified the age dimension and group the data.

Step 7: Render the table

Now, render the grid using the coding below −

.size(Infinity)
   .columns([''name'', ''DOB''])
   .sortBy(function (d) {
      return d.value;
   })
   .order(d3.ascending);

barChart.render();
countChart.render();
tableChart.render();

Here, we have sorted the columns using the DOB and sort the records.

Step 8: Working example

The complete code is as follows. Create a web page datatable.html and add the following changes to it.

<html>
   <head>
      <title>DC datatable sample</title>
      <link rel = "stylesheet" type = "text/css" href = "css/bootstrap.css">
      <link rel = "stylesheet" type = "text/css" href = "css/dc.css"/>
   
      <style>
         .dc-chart { font-size: 12px; }
         .dc-table-group { padding-left: 10px; font-size: 14px; font-weight: bold; }
         .dc-table-column { padding-left: 10px; font-size: 12px; font-weight: normal; }
      </style>

      <script src = "js/d3.js"></script>
      <script src = "js/crossfilter.js"></script>
      <script src = "js/dc.js"></script>
   </head>
   
   <body>
      <div>
         <div style = "width: 600px;">
            <div id = "mystats" class = "dc-data-count" style = "float: right">
               <span class = "filter-count"></span> selected out of <span
               class = "total-count"></span> | <a href = "javascript:dc.filterAll();
               dc.renderAll();">Reset All</a>
            </div>
         </div>

         <div style = "clear: both; padding-top: 20px;">
            <div>
               <div id = "line"></div>
            </div>
         </div>

         <div style = "clear: both">
            <div id = "mytable"></div>
         </div>
      </div>

      <script language = "javascript">
         var barChart = dc.barChart(''#line''); // , ''myChartGroup'');
         var countChart = dc.dataCount("#mystats");
         var tableChart = dc.dataTable("#mytable");

         d3.csv("data/people.csv", function(errors, people) {
            var mycrossfilter = crossfilter(people);

            // age dimension
            var ageDimension = mycrossfilter.dimension(function(data) { 
               return ~~((Date.now() - new Date(data.DOB)) / (31557600000)) 
            });
            var ageGroup = ageDimension.group().reduceCount();

            barChart
               .width(400)
               .height(200)
               .x(d3.scale.linear().domain([15,70]))
               .yAxisLabel("Count")
               .xAxisLabel("Age")
               .elasticY(true)
               .elasticX(true)
               .dimension(ageDimension)
               .group(ageGroup);

            countChart
               .dimension(mycrossfilter)
               .group(mycrossfilter.groupAll());

            tableChart
               .dimension(ageDimension)
               .group(function (data) {
                  return ~~((Date.now() - new Date(data.DOB)) / (31557600000));
               })
               .size(Infinity)
               .columns([''name'', ''DOB''])
               .sortBy(function (d) {
                  return d.value;
               })
               .order(d3.ascending);

            barChart.render();
            countChart.render();
            tableChart.render();
         });
      </script>
   </body>
</html>

Now, request the browser and you will see the following response.