Node Postgres insert multiple rows based on array and static variable - sql

Question

I am trying to insert multiple rows into a PostgresSQL server from my Nodejs server based on an array. I have a static variable, user_id, which would be the same for all entries but I want to change the filter_name based off an array. My goal is to not make multiple SQL insert calls.
arrayOfFilters = ["CM", "CBO", "SA", "EPS", "AD"]
await db.query(
"INSERT INTO filters(filter_name, requests_id)VALUES($1, $2)",
[arrayOfFiltersParams, user_id]);
I am hoping to have a row in the filters table for each one of the filters found in the arrayOfFilters with a matching user_id key for each entry (aka 5 rows for this example).
Thanks so much!

Answer 1

Write a helper function expand to build Parameterized query. Here is a solution:
import { pgclient } from '../../db';
function expand(rowCount, columnCount, startAt = 1) {
var index = startAt;
return Array(rowCount)
.fill(0)
.map(
(v) =>
`(${Array(columnCount)
.fill(0)
.map((v) => `$${index++}`)
.join(', ')})`,
)
.join(', ');
}
function flatten(arr) {
var newArr: any[] = [];
arr.forEach((v) => v.forEach((p) => newArr.push(p)));
return newArr;
}
(async function test() {
try {
await pgclient.connect();
// create table
await pgclient.query(`
CREATE TABLE IF NOT EXISTS filters (
id serial PRIMARY KEY,
filter_name VARCHAR(10),
requests_id INTEGER
)
`);
// test
const arrayOfFilters = ['CM', 'CBO', 'SA', 'EPS', 'AD'];
const user_id = 1;
const arrayOfFiltersParams: any[] = arrayOfFilters.map((el) => [el, user_id]);
await pgclient.query(
`INSERT INTO filters(filter_name, requests_id) VALUES ${expand(arrayOfFilters.length, 2)}`,
flatten(arrayOfFiltersParams),
);
} catch (error) {
console.log(error);
} finally {
pgclient.end();
}
})();
After executed above code, check the database:
node-sequelize-examples=# select * from "filters";
id | filter_name | requests_id
----+-------------+-------------
1 | CM | 1
2 | CBO | 1
3 | SA | 1
4 | EPS | 1
5 | AD | 1
(5 rows)