Myself and the other Technology Architects often have to explain to customers and vendors Caché IO requirements and the way that Caché applications will use storage systems. The following tables are useful when explaining typical Caché IO profile and requirements for a transactional database application with customers and vendors.  The original tables were created by Mark Bolinsky.

In future posts I will be discussing more about storage IO so am also posting these tables now as a reference for those articles. 

Checking if Directory or File Exists:

Outlined below is an example of how to check if a directory exists:

Set directoryName="c:\temp\nosuchdir"

/* Check for existence of a directory - Return Value:  0 - directory does not exist;  1 - directory does exist  */

Set directoryExists=##class(%File).DirectoryExists(directoryName)

If ('directoryExists)  // do the processing for when a directory does not exist

Outlined below is an example of how to check if a file exists:

This is a detailed guide to develop RESTful services using InterSystems Ensemble. The goal of this guide is to make you understanding the basic concept and building blocks of a RESTful service. The service is going to provide a very basic functionality (a “Hello world!”).

You will learn how to create required components as Ensemble classes, configure the run-time as an Ensemble Production and create a service configuration as a web application.

Ansible helped me solve the problem of quickly deploying Caché and application components for Data Platforms benchmarks. You can use the same tools and methodology for standing up your test labs, training systems, development or other environments. If you deploy applications at customer sites you could automate much of the deployment and ensure that system, Caché and your application are configured to your applications best practice standards.

Some time ago I got a WRC case transferred where a customer asks for the availability of a raw DEFLATE compression/decompression function built-in Caché.

When we talk about DEFLATE we need to talk about Zlib as well, since Zlib is the de-facto standard free compression/decompression library developed in the mid-90s.

Zlib works on particular DEFLATE compression/decompression algorithm and the idea of encapsulation within a wrapper (gzip, zlib, etc.).
https://en.wikipedia.org/wiki/Zlib

Date range queries going too slow for you?  SQL Performance got you down?  I have ANOTHER weird trick that SQL Developers don't want you to know!*

In our last lesson, we implemented a linkage to our WidgetAccessory class, and debugged some errors we encountered along the way.  We now have our data being returned by REST, but what if we want to update or add new data to our application?  

One of the benefits of Atelier is easy integration with source code management tools. Some Eclipse installations include the EGit plugin, or you can install it from the Eclipse marketplace. EGIt makes integration with Git and GitHub easy. Here are the steps I used to connect Atelier to a GitHub repository:

Globals, these magic swords for storing data, have been around for a while, but not many people can use them efficiently or know about this super-weapon altogether.

If you use globals for tasks where they truly shine, the results may be amazing, either in terms of increased performance or dramatic simplification of the overall solution (1, 2).

Globals offer a special way of storing and processing data, which is completely different from SQL tables. They were first introduced in 1966 in the M(UMPS) programming language, which was initially used in medical databases. It is still used in the same way, but has also been adopted by some other industries where reliability and high performance are top priorities: finance, trading, etc.

Later M(UMPS) evolved into Caché ObjectScript (COS). COS was developed by InterSystems as a superset of M. The original language is still accepted by developers' community and alive in a few implementations. There are several signs of activity around the web: MUMPS Google group, Mumps User's group), effective ISO Standard, etc.

Modern global based DBMS supports transactions, journaling, replication, partitioning. It means that they can be used for building modern, reliable and fast distributed systems.

Globals do not restrict you to the boundaries of the relational model. They give you the freedom of creating data structures optimized for particular tasks. For many applications reasonable use of globals can be a real silver bullet offering speeds that developers of conventional relational applications can only dream of.

Globals as a method of storing data can be used in many modern programming languages, both high- and low-level. Therefore, this article will focus specifically on globals and not the language they once came from.

ObjectScript has at least three ways of handling errors (status codes, exceptions, SQLCODE, etc.). Most of the system code uses statuses but exceptions are easier to handle for a number of reasons. Working with legacy code you spend some time translating between the different techniques. I use these snippets a lot for reference. Hopefully they're useful to others as well.

A beginners guide to develop Ensemble RESTful web services.

Background

Before you start reading this short introduction please go through the on-line documentation of Ensemble with special attention to chapter “Creating REST services and clients with Ensemble”.

The approach in the documentation is undisputable the fastest and easiest way to create RESTful services. As a beginner I went through the documentation and I had several questions. This short article is listing those questions plus my humble answers.

Background

InterSystems IRIS 2019 is going to introduce new and exciting features. One of the areas with new interesting must-to-know things is the API Management. 

InterSystems is delighted to announce the support of Docker container technology as a platform from the moment 2016.1 will be released.

Introduction

The common requirement in many applications is logging of data changes in a database - which data has changed, who changed them and when (audit logging). There are many articles about this question and there are different approaches on how to do that in Caché.