As RisingWave is wire-compatible with PostgreSQL, you can use third-party PostgreSQL drivers to interact with RisingWave from your Node.js applications.

In this guide, we use the Node.js pg driver to connect to RisingWave.

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Run RisingWave

To learn about how to run RisingWave, see Run RisingWave.

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Install npm

npm install pg

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Connect to RisingWave

You can use either a client or a connection pool to connect to RisingWave. If you are working on a web application that makes frequent queries, we recommend that you use a connection pool. The code examples in this topic use connection pools.

Connecting to RisingWave and running a query is normally done together. Therefore, we include a basic query in the code. Replace it with the query that you want to run.

const { Pool } = require('pg')

const credentials = {
  user: 'root',
  host: '127.0.0.1',
  database: 'dev',
  password: 'secret',
  port: 4566,
}
 
const start = async () => {
    const pool = new Pool(credentials);
    const res = await pool.query("SELECT 1+2"); /*A basic query to ensure the connection is successful. 
    Replace it with your own query. */
    console.log(res); //Print out the results.
    await pool.end();
}

start().catch(console.error);

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Create a source

The code below creates a source walk with the datagen connector. The datagen connector is used to generate mock data. The walk source consists of two columns, distance and duration, which respectively represent the distance and the duration of a walk. The source is a simplified version of the data that is tracked by smart watches.

const { Pool } = require('pg')

const credentials = {
    user: 'root',
    host: '127.0.0.1',
    database: 'dev',
    password: 'secret',
    port: 4566,
}

const createsource = `CREATE TABLE walk(distance INT, duration INT)
WITH ( connector = 'datagen',
    fields.distance.kind = 'sequence',
    fields.distance.start = '1',
    fields.distance.end  = '60',
    fields.duration.kind = 'sequence',
    fields.duration.start = '1',
    fields.duration.end = '30',
    datagen.rows.per.second='15',
    datagen.split.num = '1'
) FORMAT PLAIN ENCODE JSON`;

const start = async () => {
    const pool = new Pool(credentials);
    const res = await pool.query(createsource);
    console.log(res);
    await pool.end();
}
start().catch(console.error);

All the code examples in this guide include a section for connecting to RisingWave. If you run multiple queries within one connection session, you do not need to repeat the connection code.

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Create a materialized view

The code in this section creates a materialized view counter to capture the latest total distance and duration.

const { Pool } = require('pg')

const credentials = {
    user: 'root',
    host: '127.0.0.1',
    database: 'dev',
    password: 'secret',
    port: 4566,
}

const createmv = `CREATE MATERIALIZED VIEW counter
    AS SELECT
    SUM(distance) as total_distance,
    SUM(duration) as total_duration
    FROM walk`;

const start = async () => {
    const pool = new Pool(credentials);
    const res = await pool.query(createmv);
    console.log(res);
    await pool.end();
}
start().catch(console.error);

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Query a materialized view

The code in this section queries the materialized view counter to get the real-time data.

const { Pool } = require('pg');

const credentials = {
    user: 'root',
    host: '127.0.0.1',
    database: 'dev',
    password: 'secret',
    port: 4566,
}

const start = async () => {
    const pool = new Pool(credentials);
    const res = await pool.query("SELECT * from counter;");
    console.log(res.rows); // Print out only the actual data.
    await pool.end();
}
start().catch(console.error);

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