Before we start talking about databases and different data models that exist, first we'd better talk about what a database is and how to use it.

A database is an organized collection of data stored and accessed electronically. It is used to store and retrieve structured, semi-structured, or raw data which is often related to a theme or activity.

At the heart of every database lies at least one model used to describe its data. And depending on the model it is based on, a database may have slightly different characteristics and store different types of data.

To write, retrieve, modify, sort, transform or print the information from the database, a software called Database Management System (DBMS) is used.

The size, capacity, and performance of databases and their respective DBMS have increased by several orders of magnitude. It has been made possible by technological advances in various areas, such as processors, computer memory, computer storage, and computer networks. In general, the development of database technology can be divided into four generations based on the data models or structure: navigational, relational, object and post-relational.

As you can see in my profile I teach at a university and I wanted to share my take on teaching IRIS (or Caché before it).

It’s been some time but I remember seeing a series of articles by @Yuri Marx earlier this year about the course “Developing with InterSystems Objects and SQL”. He actually gave a brief description of what’s done on Day 1, Day 2, and Day 3 with comments from instructor @Joel Solon. And I thought to myself, it may be interesting to share my experience.

In the first installment of this article series, we discussed how to read a “big” chunk of data from the raw body of an HTTP POST method and save it to a database as a stream property of a class. Now let’s look at how to save such data and metadata in JSON format.

Some readers of my previous article, Caché eXTreme for .NET - direct access to globals from C#, wondered if you could access information not just from the same instance in which you’re working, but also from another instance on the same computer, or from an instance located on another computer in the same local network. Some theorized, correctly, that this would be possible using the Enterprise Cache Protocol (ECP). In this article I’m going to show how it can be done.

If you’ve ever wondered whether there is a way to regulate access to resources in Caché, wonder no more. In version 2014.2 special classes were added that allow developers to work with semaphores.