This is a translation of the following article. Thanks [@Evgeny Shvarov] for the help in translation.

This post is also available on Habrahabr^ru.

The post was inspired by this Habrahabr article: Interval-associative array^ru→en.

Since the original implementation relies on Python slices, the Caché public may find the following article useful: Everything you wanted to know about slices^ru→en.

Note: Please note that the exact functional equivalent of Python slices has never been implemented in Caché, since this functionality has never been required.

And, of course, some theory: Interval tree^ru→en.

All right, let’s cut to the chase and take a look at some examples.

When working at a terminal prompt the %SS routine lets me see what's running on the instance:

USER>d ^%SS

But sometimes I'm only interested in knowing what's running in my namespace. In which case, here's what I use:

USER>d THIS^%SS

In addition to its general security, Caché offers SQL security with a granularity of a single row. This is called row-level security. With row-level security, each row holds a list of authorized viewers, which can be either users or roles. By default access is determined at object modification Some time ago I became interested in determining row-level security at runtime. Here's how to implement it.

I needed to use the OnGetNodeInfo callback of a Zen <dynaTree>, because this seems to be the only way to control the style separately for different levels of the tree. This post describes two discoveries I made.

How a dynaTree builds a tree via the OnGetNodeInfo callback

When you use a dynaTree with the OnGetNodeInfo callback, the dynaTree creates a series of nodes and displays them top to bottom in the order they were created.

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?

During a Caché system management training course today we discussed structural database integrity (a.k.a. physical integrity) and the tools InterSystems provides for checking integrity and fixing problems.

In my previous article, I gave an example of how to get the own image with InterSystems Caché. Now it's time to launch a project with container.

The Art of Mapping Globals to Classes (2 of 3)

If you are looking to breathe new life into an old MUMPS application follow these steps to map your globals to classes and expose all that beautiful data to Objects and SQL.

This example is going to cram in 4 or 5 different things beyond what was covered in Part 1

This is a translation of the following article. Thanks @Evgeny Shvarov for the help in translation.

Let's assume that you wrote a program that shows "Hello World!", for example:

  write "Hello, World!"

The program works and everyone is happy.

With time, however, your program becomes more complex, gets more features and you eventually need to show the same string in different languages. Moreover you don't know the number and names of these languages.

The spoiler below contains a description of how the task of multi-language localization is solved in Caché.

About the Ontodia library

Something that shot up the popularity stakes last week was this article on a very interesting initiative: RealWorld:

https://medium.com/@ericsimons/introducing-realworld-6016654d36b5

I decided it would be a good idea to use this as a way of creating an exemplar implementation of a RESTful back-end using QEWD against their published API (https://github.com/gothinkster/realworld/tree/master/api)

The results are here:

It's almost a year since I have published a series of articles explaining how to configure Cache instance as a client / resource server / authorization server. By that time, the implementation of OAuth 2.0 was still a pre-release software.

Created by Daniel Kutac, Sales Engineer, InterSystems

Part 3. Appendix

InterSystems IRIS OAUTH classes explained

In the previous part of our series we have learned about configuring InterSystems IRIS to act as an OAUTH client as well as authorization and authentication server (by means of OpenID Connect). In this final part of our series we are going to describe classes implementing InterSystems IRIS OAuth 2.0 framework. We will also discuss use cases for selected methods of API classes.

The API classes implementing OAuth 2.0 can be separated into three different groups according to their purpose. All classes are implemented in %SYS namespace. Some of them are public (via % package), some not and should not be called by developers directly.

Say you have a global in one database that you instead want to map from a different database. If you just create a global mapping to the new database, the existing global will become inaccessible because it still lives on the old database. The documentation notes this problem here but doesn't give details on how to fix it.