Load data into and retrieve data from the Qlik Associative Engine running in a Docker container.
Clone the Get Started Git repository to your local machine. The Hello tutorials are located here, and all commands should be executed from this Git repository.
You must have Node.js and npm installed on your local machine.
Make sure the Qlik Associative Engine is running. Run
docker-compose up -d
command in a command shell to start the engine in a Docker container.
If you are unfamiliar with starting the Qlik Associative Engine in a Docker container, we
recommend that you begin with the Hello Engine tutorial.
Loading and retrieving data¶
To load and retrieve data, you will run a small Node.js application that loads data into, and then retrieves that data from the Qlik Associative Engine.
The application consists of the
hello-data.js file and the
file, which is also shared among the Hello Data and
Hello Visualization tutorials.
If you already installed the dependencies in the previous tutorial, go to step 2.
Run the following command from a command shell:
This command installs all of the dependent packages in the
Run the application.
Run the following command in a command shell:
npm run hello-data
This command runs the application, which creates a representation of the data and loads it into Qlik Associative Engine as a part of opening a session.
What is happening¶
When you start Qlik Associative Engine, the
docker-compose.yml file makes the
available to Qlik Associative Engine, and the data location is specified in the volumes section.
volumes: - ./data:/data
To learn more about volumes, see Use volumes.
To load data, the
hello-data application executes a load script in Qlik Associative Engine that loads data
movies.csv file available to the engine on the local file system. enigma.js is used to open a session and
create a session object that holds the first 10 movie titles. The application then retrieves the movie titles from the
dataset, prints the results, and closes the session.
If the application runs successfully, you will see the list of 10 movies from the dataset.
$ npm run hello-data Creating table data representation. Creating and opening session using mixin. Creating session object with movie titles. Listing the 10 first movies: 2012 Armageddon Avatar Battleship Cars 2 Cleopatra Evan Almighty Green Lantern Harry Potter and the Half-Blood Prince Indiana Jones and the Kingdom of the Crystal Skull Session closed.
file to inspect how the load script and enigma.js are used to load and retrieve data from the
Qlik Associative Engine.
You might see some unfamiliar details of the Qlik Associative Engine in the source code.
For example, the
properties object that is used to create the session object contains a field called
qHyperCubeDef. This relates to the central concept of hypercubes in the Qlik Associative Engine.
To learn more about hypercubes, see
In the example above, the hello-data application executes a load script that specifies how data from a CSV file is loaded into Qlik Associative Engine.
Rather than directly using a load script, you can use the halyard.js library, which provides a convenient way to do similar data loading tasks without the need to write load scripts because halyard.js generates them for you.
Here is an equivalent implementation of the hello data example, but now using halyard.js instead.
Run the following command:
npm run hello-data-halyard
You should see output similar to the previous example, with the 10 first movie titles printed.
What is happening¶
In this example, the load script is now replaced by a halyard.js table representation of the data, which is used to load
data into the Qlik Associative Engine as part of opening a session. Then, it uses enigma.js mixin support to create a
session object that holds the first 10 movie titles from the
movies.csv dataset. The application then retrieves the
movie titles from the dataset, prints the results, and closes the session, just as in the previous example.
file to inspect how halyard.js and enigma.js are used to load and retrieve data from the Qlik Associative Engine.
Continue with the Hello Visualization tutorial to learn how to display the data that you loaded in this tutorial as a scatter plot.