Mongodb – updating related relations in database
i have created groups , which has members , each member has a group array displaying which they are part of . if i delete a group i want that user's group array also updates. i am using express and…
Javascript and Excel DB
I made a Javascript nodejs project that stores data in Excel. I can access all columns in the entire file without any problems, but the value of the cells containing time information(12:30) is given as numbers(0.6423611111111112). Is it possible to…
Postgresql – What is the most suitable data type for a column in a table?
Currently I'm trying to develop a PostgreSQL database schema, it has only 2 tables, one of which contains usernames. The difficulty is that for certain reasons I cannot store the username directly, so I have to store the hash (SHA256).…
Postgresql – How to system-design paying a payment with multiple currencies
I am developing an accounting app where users can have a product with currency A. The value of the product can be escrowed using a cheque payment with currency B and this cheque payment can be paid in cash with…
Postgresql – postgres – How to parse json array elements?
Below is the postgres table table1: CREATE TABLE table1 ( id INT PRIMARY KEY, name TEXT, skills JSON ); with below rows inserted: INSERT INTO table1 (id, name, skills) VALUES (1, 'Alice', ‘[ {“sid" : 11, "description" : “Cardio"}, {"sid"…
PostgreSQL tries to connect to wrong DB
Postgresql tries to connect to a Db with the same name as the user, even when I specify the DB name in the connection string. Cadena de conexión: host=localhost port=5432 user=carsUser password= dbname=the-new-cars sslmode=disable 2024/06/22 16:00 Error al hacer ping…
Postgresql – To display customers who have made a large number of orders in a certain time range for all time in SQL
There is a database with online store customers, which has the following data: id buyer's; order number; date and time of the order; order amount. Data on customers and orders for 3 months. How to withdraw customers who made more…
Postgresql – How to Efficiently Track Latest IoT Data Timestamps for Multiple Vehicles?
I'm working on an application where I need to monitor the latest IoT data being sent from a fleet of over 3000+ vehicles. Each vehicle is equipped with an IoT device that sends data to an Iotdata table. To determine…
Mysql – What is the difference between these 2 queries?
(sale_id, year) is the primary key (combination of columns with unique values) of this table. product_id is a foreign key (reference column) to Product table. Each row of this table shows a sale on the product product_id in a certain…
MongoDB run loop to add incremental index value in array
I have a MongoDB collection where I have an array of objects and I want to add an incremental index value to each element of the array of objects. Like index starts from 0 to array length - 1. db.collection.aggregate([…