Introduction In this tutorial, we will build a registration system that allows users of your Postgres- and Python-based web application to create a username and password, add the new user to our database, send that new user a confirmation email, receive a response from their click on the link we sent them in that email, … Continued
Introduction When you’re querying a database, there are times when you don’t necessarily need the data in the rows themselves, but you need to know how many rows in a table meet certain criteria. PostgreSQL makes queries like these simple with the COUNT command, an aggregate function that returns the number of rows in a … Continued
Introduction Making complex statements in queries when searching for data in tables is a common task. That’s because there are often times when you’ll want to run a second query on the first set of results that were returned. Although it can pose challenging, the good news is that you can do it seamlessly and … Continued
Introduction to the psycopg2 PostgreSQL adapter for Python If you’re planning to connect to your PostgreSQL database from a Python script, you’ll need an adapter to allow Python to interact with PostgreSQL. One of the most popular PostgreSQL adapters for Python is the psycopg2 adapter. In this article, we’ll show you how to connect to … Continued
Introduction There has been so much talk lately about MapReduce and how it can help developers process large data sets into useful aggregated results. In this tutorial, we are going to show you some examples using the MapReduce() function on a MongoDB collection. MapReduce is broken down into two phases: The map phase filters out … Continued
Introduction In this five-part tutorial, we will create a sign-in system that allows users of your Postgres- and Python-based web application to enter their email and password, check their entry against the email and hashed password we have in the database, and even offer a “I forgot my password” feature that involves sending a link … Continued
Introduction When you retrieve data in PostgreSQL, you’ll probably want your results to be sorted in a certain way. In PostgreSQL, you can specify the sort order of your results with the ORDER BY clause. This clause allows you to specify the column by which you’d like to sort your results, and it also allows … Continued
Introduction When you’re working with PostgreSQL, you’ll find that you may need to add a column or two to an existing table. This task is made simple with the help of the Postgres ALTER TABLE and ADD COLUMN statements. In this article, we’ll explain how to use these statements to add multiple columns to a … Continued
Introduction This tutorial will explain how to use the PostgreSQL alter a table statement to add or change data in a PostgreSQL table. The PostgreSQL ALTER TABLE statement can be used to change how a table was initially structured. This is a very useful function during database audits, software development or accommodating various business requirement. … Continued
Introduction If you’re using PostgreSQL, you may need to remove the package from your system at some point. It’s important to know how to uninstall PostgreSQL properly to make sure all components of the package are completely removed and you don’t encounter any errors. In this article, we’ll explain how to uninstall PostgreSQL from Linux, … Continued
