JavaScript

JavaScript Client

You can use node-postgres to connect to CedarDB.

Installing

You can install the node-postgres library directly from npm:

npm install pg

Now you can use node-postgres:

import pg from 'pg'
const { Client } = pg

Connecting

Connect to CedarDB like this:

const client = new Client({host: 'localhost', user: '<username>', password: '<password>', database: '<dbname>'})
await client.connect()

Inserting Data

You can insert entries using queries:

await client.query('create table chatlog(userid integer, message text, ts timestamp)');
await client.query({text: 'insert into chatlog values ($1, $2, $3)', values: [0, 'hello', new Date()]});

You can now query the data contained in the table:

console.log((await client.query('select * from chatlog')).rows)

Batching

To efficiently execute many queries, you can batch the queries into one async transaction to avoid the repeated round-trip latency. Or insert a set of data:

let promises = []
promises.push(client.query('begin'))
for (let i = 1; i < 100; i++) {
    const query = {name: 'do-insert', text: 'insert into chatlog values ($1, $2, $3)', values: [i, 'hello', new Date()]}
    promises.push(client.query(query));
}
promises.push(client.query('commit'))
await Promise.all(promises)

Source Code

Open to show the complete sample code

'use strict';

// Install dependencies with:
// $ npm install pg
const { default: pg } = await import("pg");
const { Client } = pg;

// Connect to CedarDB
const client = new Client({host: '/tmp', user: 'postgres', database: 'postgres'});
await client.connect();

// Create a table and insert some data
await client.query('create table chatlog(userid integer, message text, ts timestamp)');
await client.query({text: 'insert into chatlog values ($1, $2, $3)', values: [0, 'hello', new Date()]});

// Execute a query
console.log(await client.query('select * from chatlog'))

// Insert many values asynchronously
let promises = []
promises.push(client.query('begin'))
for (let i = 1; i < 100; i++) {
    const query = {name: 'do-insert', text: 'insert into chatlog values ($1, $2, $3)', values: [i, 'hello', new Date()]}
    promises.push(client.query(query));
}
promises.push(client.query('commit'))
await Promise.all(promises)

// Read all values back again
console.log(await client.query('select * from chatlog'))

await client.end()

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