Creating DataModel Instances

Basic Instance Creation

To create a DataModel instance, use the following constructor:

const dataModelObject = new DataModel(formattedData);

The constructor expects formatted data from DataModel.loadData() as its input parameter.

Complete Example

Here's a step-by-step walkthrough of creating and accessing a DataModel instance:

const DataModel = muze.DataModel;

// Define the schema
const schema = [
  {
    name: "Name",
    type: "dimension",
  },
  {
    name: "Maker",
    type: "dimension",
  },
  {
    name: "Horsepower",
    type: "measure",
    defAggFn: "avg",
  },
  {
    name: "Origin",
    type: "dimension",
  },
];

// Prepare the raw data
const rawData = [
  {
    Name: "chevrolet chevelle malibu",
    Maker: "chevrolet",
    Horsepower: 130,
    Origin: "USA",
  },
  {
    Name: "buick skylark 320",
    Maker: "buick",
    Horsepower: 165,
    Origin: "USA",
  },
  {
    Name: "datsun pl510",
    Maker: "datsun",
    Horsepower: 88,
    Origin: "Japan",
  },
];

// Format the data
const formattedData = await DataModel.loadData(rawData, schema);

// Create the DataModel instance
const dataModelObject = new DataModel(formattedData);

// Access the formatted data and schema
const { data, schema } = dataModelObject.getData();

// Log the internal data structure
console.log(data);

Data Structure

The getData() method returns an object with two properties:

• data: A two-dimensional array in column-major order where:

  • Each array represents a column of values
  • Column order matches the schema field order
  • This format optimizes DataModel's internal operations

• schema: A reference to the schema used to create the instance

  • Maintains field definitions and metadata
  • Used for data validation and operations

Working with DataModel Instances

Once created, a DataModel instance provides access to:

• The underlying data through getData()
• Various transformation operations that create new DataModel instances
• The schema information used to interpret the data

Each operation performed on a DataModel instance creates a new instance, maintaining the immutable architecture discussed in the introduction.