Connecting to an SQL database through Catalyst functions

Connecting to an SQL database through Catalyst functions

Hey there, 

Are you looking to connect to a PostgreSQL database. Here is a sample Nodejs function that can connect to a database remotely and provide scalable API endpoint to retrieve list of tables.
Here, the GET method is 'GET' and the endpoint is '/query'.

Make sure that you install express and postgres-pool packages in your advanced I/O function using "npm install --save  <<package_name>>"
  2. var express = require('express');
  3. var app = express();
  4. const { Pool } =require('postgres-pool');
  5. const QUERY="SELECT * from information_schema.tables where table_schema = 'public'"
  6. const pool = new Pool({
  7. connectionString: 'postgres://user_name:password@127.0.0.1/db_name',
  8. });
  9. function getDBdata() {
  10. return new Promise((resolve, reject) => {
  11. pool.query(QUERY).then(queryResponse => {
  12. resolve(queryResponse.rows);
  13. }).catch(err => {
  14. reject(err);
  15. })
  16. });
  17. }
  18. app.get('/query', function (req, res) {
  19. getDBdata().then(
  20. rows => {
  21. var html = "<h1> List of Tables in DB</h1>";
  22. rows.forEach(element => {

  24. html = html.concat('<li>' + element.table_name + '</li><br/>');
  25. });
  26. res.send(html);
  27. }).catch(err => {
  28. console.log(err);
  30. })
  31. });

  33. module.exports = app;


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