Category: Data Storage and Retrieval

Npgsql Insert Time Without Timezone

I’m just getting started with Npgsql for .NET Core Entity Framework and I ran into some trouble trying to do an insert into a Postgres table with a time data type. I initially tried to use a DateTime object, as worked with the date data type, but that didn’t work. The documentation said to use […]

PostgreSQL Quickstart

I’ve used mostly MySQL in the past, but a recent project called for working with PostgreSQL. The most immediate difference was that databases and schemas were semantically different. I took a liking to the DBMS – database management system, and plan to be using it in future projects. So, here I will notate some commands […]

MySQL and Python3

I’m using Python more and more so it’s not surprising that recently the need arose to connect to and insert into a MySQL database. I was using (and usually do) Python3, and I ran into a couple of issues in the begining. This post will document those issues and the solutions I found to get […]

SQLite3 Database Quick Create with Bash

In this post, I will document a couple of cases where one can quickly create an SQLite3 database by issuing commands in a Bash shell (the default terminal shell in Linux and Mac OS X). Case 1: Create a database with a table for images containing rows/tuples with the image url and a caption for […]

SQL Aggregation, Grouping, and Having

Aggregating In SQL, the standard aggregation operators are SUM, MIN, MAX, and COUNT and we can apply them to the attributes of relations. For example we have a schema employee(eid, name, dob, hired_date, salary), which holds records on each of a company’s employees. We can COUNT and see how many employees the company has with […]