I have also included a course on Oracle and Microsoft SQL Server, two of the most popular database of the modern world which enhance SQL with some proprietary features.ġ. You will learn how to write SQL queries, both basic and advanced like using joins and aggregate functions, etc. In this article, I'll share courses that will help you to learn the basics of SQL and Databases. I bought it for just $10 on the Udemy sale.ĥ FREE Udemy Courses to Learn Database and SQL Online in 2022 It's a very hands-on and comprehensive course and very affordable too.

Btw, If you don't mind investing a few bucks on your learning then I also suggest you check out The SQL Bootcampcourse by Jose Portilla on Udemy. It helps you to understand the data, an important part of your application as well as during troubleshooting. Good knowledge of SQL needs to effectively do your job. It allows you to query data to find what you are interested in.įor example, if you are working for an e-commerce giant like Amazon then you can pull out the best-selling items by writing an SQL query. Most real-world applications use relational data in one way or another and SQL is the query language to work with those data. And it seems to stay that way for years to come. Over time, it has only advanced with new features and standards. While many languages that existed two decades ago are extinct now, SQL has always maintained its supremacy in the RDBMS world. SQL is one of the important programming languages to interact with various Database Systems for many decades.

As per ANSI (American National Standards Institute), SQL stands for the Standard Query language for Relational Database Management Systems. However, I would have to create a table for each user which doesn't seem good design to me and can come with many problems.The SQL is used to interact with Database Systems like Oracle, MySQL, and Microsoft SQL Server. Problem: To me, it seems faster to search for interactions because every time the user accesses its notifications I just need his ID. Method 2: On the other hand, for the user table I can create a field which links to an interactions table that links with a table of interactions from that user - so each user has an interactions table from himself to other users. I would guess this is time-consuming and heavy processing. Problem: Each time a user wants to access its interactions I will have to look into ALL interactions from ALL users ion the table interactions and find, specifically, every instance of interaction with that user. Method 1: I have an interactions table where two of the attributes are userID1, userID2 and the type of the interaction. In a relational database, what would be the best way to implement a relationship where several users each have several interactions with each other?

Best free relational database developer