Article
· Mar 4, 2022 4m read
How to become a time lord - Time travel

Time travel is like visiting Paris. You can't just read the guide, you have to throw yourself into it. Eat the food, use the wrong verbs, get double the charges, and end up kissing complete strangers.

The Doctor

We are now going to travel through time, that is, we are going to see future and past dates and how to calculate them in different formats. The TARDIS doesn't wait, take the controls and hold on tight.

Travel in TARDIS

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At the heart of IRIS and Cache is a very interesting database architecture that we, at M/Gateway Developments, refer to as "Global Storage". If you ever wanted to know more about the fundamentals and capabilities of this underlying database, you might want to read a major analysis we've put together:

https://github.com/robtweed/global_storage

Amongst other things you'll discover that:

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This announcement is to inform clients about changes in our 2016.2 and 2016.3 field test programs.

The 2016.2 field test has been extended in order to address important syntax changes related to JSON. Simply stated, the JSON syntax introduced in 2016.1 had several inconsistencies that we did not want to perpetuate. This is now addressed and the updated 2016.2 field test will be published today. Concurrently, the syntax changes and guidance for developers will be posted on the Developer Community shortly. JSON is critically important to our Caché roadmap.

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This text is a continuation of my article where I explained the structure a Caché database. In this article, I described the types of blocks, connections between them and their relation to globals. The article was purely theoretical. I made a project that helps visualize the block tree - and this article will explain how it works in great detail.

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In this article, I would show how you can upload and download files from InterSystems products via http.

The questions about working with files over http arise fairly often on community and I'm usually linking to my FileServer project which demonstrates file upload/download but I'd like to talk a bit more on how we can serve and receive files from InterSystems products.

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Article
· Feb 11, 2019 4m read
Using Oauth2 with SOAP (Web)Services

Hi guys,

Couple days ago, a customer approached me with the wish to enhance their existing legacy application, that uses SOAP (Web)Services so it shares the same authorization with their new application API based on REST. As their new application uses OAuth2, the challenge was clear; how to pass access token with SOAP request to the server.

After spending some time on Google, it turned out, that one of possible ways of doing so was adding an extra header element to the SOAP envelope and then making sure the WebService implementation does what is needed to validate the access token.

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In the previous parts (1, 2) we talked about globals as trees. In this article, we will look at them as sparse arrays.

A sparse array - is a type of array where most values assume an identical value.

In practice, you will often see sparse arrays so huge that there is no point in occupying memory with identical elements. Therefore, it makes sense to organize sparse arrays in such a way that memory is not wasted on storing duplicate values.

In some programming languages, sparse arrays are part of the language - for example, in J, MATLAB. In other languages, there are special libraries that let you use them. For C++, those would be Eigen and the like.

Globals are good candidates for implementing sparse arrays for the following reasons:

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Article
· Jun 12, 2017 1m read
Setting the Windows service account

I recently helped a site investigate a problem that appeared after they upgraded their Windows instance of Caché from 2015.1 to 2017.1. A terminal session launched from the server's desktop cube was unable to run OS-level commands using the $ZF(-1) function. For instance, using the no-op command "REM" as follows:

write $zf(-1,"rem")

was returning -1, indicating that the Windows command could not be issued.

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Article
· Mar 3, 2016 2m read
Class Projections and Projection Classes

The purpose of this post is to raise the profile of a powerful mechanism that has long been available to us, and to open a discussion about ways in which it can be used or abused.

You can read more detail about the mechanism here. To summarize, your class definition can use the Projection keyword to reference one or more projection classes. A projection class can implement methods that get invoked at key points in the lifecycle of your class.

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Article
· Jul 18, 2017 2m read
Old/New Dynamic SQL Cheat Sheet

The newer dynamic SQL classes (%SQL.Statement and %StatementResult) perform better than %ResultSet, but I did not adopt them for some time because I had learned how to use %ResultSet. Finally, I made a cheat sheet, which I find useful when writing new code or rewriting old code. I thought other people might find it useful.

First, here is a somewhat more verbose adaptation of my cheat sheet:

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Hi community!

I want to introduce you a new powerful feature from our static code analyzer objectscriptQuality.

Each time a new IRIS version is released, you need to prepare a roadmap for migration in which you need to spend a lot of time on testing to find where your code is not accomplishing with the newer version. Or maybe you need your code to be compatible with multiple IRIS or Caché versions.

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Article
· Nov 2, 2023 3m read
How to hide the source program

InterSystems FAQ rubric

For routines (*.mac)

You can hide the source by exporting/importing only the *.obj that is generated after compiling the source program.

The command execution example specifies EX1Sample.obj and EX2Sample.obj, which are generated by compiling EX1Sample.mac and EX2Sample.mac, as export targets and exports them to the second argument file.

After moving to another namespace, I am using the exported XML file to perform the import.

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If you have system tables implementing the "VERSIONPROPERTY" functionality, you may encounter error 5800. This article explains how this error occurs and provides solutions to resolve the issue.

When version checking is implemented, the property specified by VERSIONPROPERTY is automatically incremented each time an instance of the class is updated (either by objects or SQL).

For example:

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The latest WebComponent-based, SB Admin 2-themed QEWD Monitor application now includes a cool D3-based viewer for visualising your IRIS or Cache Globals - see example below

This qewd-monitor-adminui application is automatically installed when you install QEWD on a Windows machine

See here for details on installing QEWD on Windows:

https://github.com/robtweed/qewd-microservices-examples/blob/master/WINDOWS-IRIS-2.md#initial-steps

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IRIS offers Durable %SYS Directory as a highly useful feature for working with containers.

Before inventing the wheel once more I'd like to know if a similar feature also exists for Caché / Ensemble.
Official documentation is quite silent about.
Though I have some names in mind that might know more about ( @Luca Ravazzolo ? @Dmitry Maslennikov ? @Eduard Lebedyuk ? )

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image

The InterSystems DBMS has a built-in technology for working with non-structured data called iKnow and a full-text search technology called iFind. We decided to take a dive into both and make something useful. As the result, we have DocSearch — a web application for searching in InterSystems documentation using iKnow and iFind.

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Article
· Jul 14, 2016 1m read
Caché Haiku

Alex Koblov posted today a #CachéHaiku:

Full command names

Make your code more readable

Than compact versions

My haiku:

Caché Globals

Shows you keys to the value

If you $order it

Your variant? ;)

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Here are a few examples of conversions and operations you might need, along with links to documentation where you can learn more.

At the time I wrote this, Eastern Daylight Time was in effect for my Caché system.

How Caché keeps the time and date

Caché has a simple time format, with a longer range of recognized dates compared to some other technologies.

The current time is maintained in a special variable $HOROLOG ($H):

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