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#Tips & Tricks

15

Pieces of experience in InterSystems Technology which solve some particular problem in elegant or unusual way.

I was recently asked whether we have a function to convert LDAP date time stamps into $HOROLOG format or other formats and the answer is not at the moment, but there is a simple method to do the conversion.

Let us look at the facts and figures involved...

1) Active Directory's (AD) date 0 (zero) is 1601-01-01 00:00:00.000 or January 1st, 1601 at midnight (00:00:00)

2) AD timestamps are calculated as the number of 100 nanosecond intervals from date 0

3) 864000000000 is the number of 100 nanosecond intervals per day

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Sometimes you can face the situation when you did update the web app on Caché server but you cannot get the newest version of the app in a browser.

Here are couple recipes which help me to solve it. From simplest to more sophisticated and not obvious.

1. Refresh page in a browser

In Chrome it is Ctrl+R or 'Refresh' button. Obvious, but helpful.

2. Hard reset in a browser

If you are in Chrome, open Developer tools

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Article
· Jan 30, 2023 2m read
JSONfile-to-Global #1

The similarity between JSON objects + arrays and Globals in IRIS or Caché is evident.
With small and medium size JSON objects navigation across %Dynamic Objects is comfortable.
But with large and/or deep cascaded objects it becomes a challenge.

The presented tool offers 3 variants

  • loading an already existing %Dyamic object or Array into a global of your choice
  • loading a %Stream containing a JSON object into a global of your choice
  • loading an external File containing a JSON object into a global of your choice

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InterSystems FAQ rubric

This error occurs when an instance of the class is already open at compile time.

There are two ways to deal with this issue:

  1. Terminate the process or application that has the instance open
  2. Compile options in the studio build menu: Check the compile flag “Compile classes in use” and compile.

If you want to determine which process is using the class, try the sample routine below.

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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:

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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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As we all know, InterSystems is a great company.

Their products can be just as useful as they are complex.

Yet, our pride sometimes prevents us from admitting that we might not understand some concepts or products that InterSystems offers for us.

Today we are beginning a series of articles explaining how some of the intricate InterSystems products work, obviously simply and clearly.

In this essay, I will clarify what Machine Learning is and how to take advantage of it.... because this time, you WILL KNOW for sure what I am talking about.

Open Exchange app
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After reading Stephen Wilson's article "Windows 7 performs shutdown too fast for Cache to close and so it gets forced down" I've recalled another solution that was based on Local Group Policy, which allows to control extra actions that should occur on computer startup or shutdown. How to add a computer shutdown script is well documented in MS Technet article.

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Article
· Feb 14, 2017 1m read
Portal tip: The inconspicuous Menu button

Amongst the large fonts and chunky icons of Portal's pages, the Menu button in the top left corner is easily overlooked:

When clicked, it often produces the following menu:

When I remember it's there, I find the "View Console Log" option particularly handy.

I wrote "often" above because I've also noticed that the Menu contents change when I'm on a page within the Ensemble section of Portal:

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Article
· Apr 24, 2017 1m read
Diagnosing the cause of <PROTECT> errors

If your application is raising <PROTECT> errors and you're finding it hard to work out why, here's a way to get additional information.

First, if auditing is not already enabled, turn it on:

Then use "Configure System Events" (highlighted above) and locate the event named %System/%Security/Protect. In the screenshot below I used the Filter field to do this (type "protect" - highlighted below - and press TAB):

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In this article I will explain the usage of %SQL_Diag.Result and %SQL_Diag.Message table along with all-new LOAD DATA functionality.

It is recommended to go through LOAD DATA documentation first.

After successful operation LOAD DATA insert one record in %SQL_Diag.Result table and details are inserted in %SQL_Diag.Message table


Below is the basic command when table is already created and source file does not contain header row. 

LOAD DATA FROM FILE 'C://TEMP/mydata.txt' 
INTO MyTable

The file name must include a .txt or .csv (comma-separated values) suffix and both source and target have the same sequence of data columns.

Loading from File Source: Header

Open Exchange app
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In Studio you could open a class directly via it's name, without having to traverse the package tree with multiple clicks until arriving at the desired class.

You would Ctrl + O or (File -> Open) and be able to simply type in the class name, for example:

You press Enter, and viola - the class is opened.

How do you achieve this in VSCode?

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What is a core file? and When are they use­ful?

The in­for­ma­tion in this doc­u­ment is cur­rent as ver­sions of InterSystems prod­ucts re­leased through 2024-06-06. This up­date date cov­ers er­rors in that dis­covered up to 2024-08-12, but not changes present in new ver­sions of InterSystems prod­ucts.

Nevertheless, the de­tails for ex­ist­ing prod­ucts are not sub­ject to fre­quent change.

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Article
· Mar 2, 2017 1m read
Trusting the code you import

As more people join Developer Community, and with increasing efforts to promote code sharing, I'd like to draw fresh attention to this post I wrote a year ago. It spotlights a feature within the class compiler which is both useful and dangerous. When importing code (e.g. from an XML export of classes received from someone), it's worth considering the risks.

Even if that post doesn't seem relevant to you at the moment you may wish to note it for the future. A handy way of doing this is to click the star icon at the end of it.

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Hi All

I'm looking for some field experiences, lessons learned, or actual deployed solutions to the problem of replicating non-CACHE.DAT data in a mirrored Cache environment.

Environment:

  • Operating System is IBM AIX
  • Hardware is IBM Power w/ virtualised storage
  • Cache 2017.1
  • 2x Production mirror members
  • 1x DR mirror member
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I asked the question in email and get answers from those colleagus.

Question:

I failed to change time zone on latest iris container(Ubuntu), because:

  • I am irisowner, no root password

  • There is no sudo command

I used to use below Dockfile setting to change time zone while creating a new docker image. However, those commands doesn’t work from non-root user.

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Here at InterSystems, we often deal with massive datasets of structured data. It’s not uncommon to see customers with tables spanning >100 fields and >1 billion rows, each table totaling hundred of GB of data. Now imagine joining two or three of these tables together, with a schema that wasn’t optimized for this specific use case. Just for fun, let’s say you have 10 years worth of EMR data from 20 different hospitals across your state, and you’ve been tasked with finding….

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Every developer has made the mistake of accidentally leaving temporary debug code in place when they meant to remove it after debugging is complete. The great thing about writing in ObjectScript is that there is a way to make temporary code be truly temporary and automatically self-destruct! This can also be done in such a way that the code has no change of making it into your source control stream, which can be helpful as well.

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Article
· Jun 1, 2023 1m read
How to shrink the IRISTemp database

InterSystems FAQ rubric

You can set the maximum size of the IRISTemp database at IRIS startup by setting a configuration parameter called MaxIRISTempSizeAtStart.

After setting, the system will truncate IRISTemp to the set value (MB) at the next IRIS startup. If the current size is less than the specified MaxIRISTempSizeAtStart, no truncation will occur. Also, if 0 is specified, truncation will not be performed, so the size will start without changing. (Default) Settings are made from the menu below.

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