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#Tips & Tricks

18

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

Article
· Feb 24 2m read
The bewitched line terminator

I want to address the nasty problems about reading a flat text in ASCII, UTF*
explicitly excluding HTML, EBCDIC, and other encoding.
According to Wikipedia there are at least 8 variations of control characters.

  • CR+LF is typical for Windows
  • LF is typical for the Linux/UNIX world
  • CR is Mac's favorite

As you can deduct from the names the inspiration comes from mechanical typewriters.

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InterSystems FAQ rubric

If the system does not stop for 24 hours, old journal files will be deleted at 0:30 according to the "Journal file deletion settings".

A possible cause of journal files remaining that are older than the "Journal file deletion settings" is that there are transactions that remain open.

In that case, you will be able to delete the journal file by searching for processes executing transactions and finalizing the transactions.

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InterSystems FAQ rubric

You can set individual error pages for the following Web Gateway error messages/system responses:

  • server error
  • server busy
  • server unavailable
  • server timeout
  • connection closed

Settings are made on the Web Gateway Management screen ([Management Portal] > [System Administration] > [Configuration] > [Web Gateway Management] > [Configuration] > [Default Parameters]).

In the Error Page section of the Default Parameters menu, set the filename of the html page to display or the URL to redirect to when an error occurs.

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Article
· Jun 8, 2023 1m read
How to write SELECT ... FOR UPDATE

InterSystems FAQ rubric

Since SELECT ... FOR UPDATE is implemented in many RDBMS as a method of explicit row lock acquisition, I think there are many cases where this function is used.

This syntax is not an error for InterSystems products, but it does not acquire row locks as expected.

This article will show you how to achieve equivalent functionality.

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InterSystems FAQ rubric

If multiple InterSystems products are installed on the same system, the latest version of the InterSystems ODBC driver among the installed products will remain registered in the driver manager.

You can change to any driver by changing the registry entry below.

Please note that running RegFiles.bat does not change the ODBC driver.

The registry entry is as follows.

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InterSystems FAQ rubric

※Use this method if you want to compare databases that have been replicated using mirroring, shadowing, or some other mechanism.

You can use the DATACHECK utility to compare global variables. Please refer to the document below.
Overview of DataCheck [IRIS]

***

Routine comparisons use the system routine %RCMP or the Management Portal.

Below is how to use it in the Management Portal.

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Article
· Jul 6, 2023 1m read
How to overload methods in ObjectScript

InterSystems FAQ rubric

The InterSystems ObjectScript language does not allow you to define methods of the same name with different arguments. It is generally classified as a programming language called a dynamic language.

In ObjectScript, you can freely control which arguments are used when executing a method, so unlike languages ​​such as Java, which are not dynamic programming languages, there is no need to strictly distinguish methods by the number of arguments at the compilation stage.

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InterSystems FAQ rubric

For volatile tables (tables with many INSERTs and DELETEs), storage for bitmap indexes can become inefficient over time.

For example, suppose that there are thousands of data with the following definition, and the operation of bulk deletion with TRUNCATE TABLE after being retained for a certain period of time is repeatedly performed.

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InterSystems FAQ rubric

If a relationship is set and there is a large number of n in a 1:n ratio, a large amount of memory may be consumed due to sequential processing of the relationship.

After referencing a many-sided object in a program and internally swizzling it, simply releasing the variable containing the OREF (deleting it, setting another value, etc.) will not free the many-sided object and the relationship object. This is the cause.

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InterSystems FAQ rubric

If the journal file is too large to be searched or filtered using the Management Portal, you can refer to it using the following two methods.

① How to use the ^JRNDUMP utility
② How to reference it in a program

================================================== ==========

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InterSystems FAQ rubric

Record maps are used to efficiently map files containing delimited records or fixed-width records to message classes used by the interoperability function, and to map files from interoperability function message classes to text files.

Record map mapping definitions can be created using the Management Portal, and we also provide a CSV record wizard that allows you to define while reading a CSV file.

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InterSystems FAQ rubric

To remove InterSystems products installed on your Windows system, use Add or Remove Programs in Control Panel (in Windows 10, select Apps from Windows Settings).

Since we will be making changes to the system, you will need to log in as a user with administrator privileges.

1) Log in to the system as an administrator.

2) From the system tray, exit the launcher of the InterSystems product instance you want to uninstall (click launcher → exit).

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Hello again everyone.

In our previous article we saw how to configure our EMPI to receive FHIR messages. To do this we installed the FHIR Adapter that InterSystems made available to us that configured a REST endpoint to which we could send our FHIR message. We would then get the message and transform it to a %String that we would send via TCP to the output of our EMPI configured in our HSPIDATA namespace.

Alright, it's time to see how we retrieve the message, transform it back to a %DynamicObject and parse it to the class used by the EMPI to store the information.

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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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We are successfully using System Default Settings to manage differences in settings across environments where the production and underlying code are otherwise identical. However, the TestingEnabled and LogGeneralTraceEvents settings don't appear to be settable via this mechanism. While we appear to be able to set them on the SDS page, they do not show up as selectable when resetting the settings on the Production Settings tab in the management portal - see screenshots below.

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InterSystems FAQ rubric

There is no need to recompile the routines after the version upgrade, but since the version update overwrites %SYS, user-created INT and OBJ format routines (*.INT,*.OBJ) in %SYS will be deleted. Therefore, you need to be careful.

MAC, INT and OBJ routines with the following names are not deleted.

%Z*.INT, %z*.INT, Z*.INT,z*.INT
%Z*.OBJ, %z*.OBJ, Z*.OBJ,z*.OBJ

Please note that classes/CSPs need to be compiled after upgrading.

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I have been walking through this with a few team members and as such I thought there might be others out there who could use it, especially if you work with HL7 & Ensemble/HealthConnect/HealthShare and never venture out past the Interoperability section.

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InterSystems FAQ rubric

You can use the %IndexBuilder class to perform index rebuilding using multiple processes.

Here is an example for the purpose of defining the standard index HomeStateIdx for the Home_State (state information of contact address) column of Sample.Person.

The steps are as follows:

1. Hide the index name to be added/rebuilt from the query optimizer.

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We are looking at what we need to do to migrate from our current usage of Zen reports to InterSystems Reports. One of the hurdles for us is figuring out ways to interact with InterSystems reports programmatically from ObjectScript routines. There is a Java API for it, but it is possible to generate a report from InterSystems reports to a stream object in ObjectScript without diving into Java by using a %Net.HttpRequest. Here is a code example, followed by an explanation:

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