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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Moving over from Studio To VSCode like many other will do now the ObjectScript plugin reached version 1.0, I noticed I was missing some items in the objectscript explorer. For example when creating a Rest API using the spec first approach, 3 classes are generated, an application.impl, application.disp and application.spec class, but the disp class was missing in the Object Explorer.

As the application.disp is a generated class, for showing these classes you need to turn this on by hitting the switch on the object explorer:

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Hello Community,

SQL language remains the most practical way to retrieve information stored in a database.

The JSON format is very often used in data exchange.

It is therefore common to seek to obtain data in JSON format from SQL queries.

Below you will find simple examples that can help you meet this need using ObjectScript and Python code.

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The Good Old Days

The %Library.DynamicObject class has been in IRIS since before it became IRIS. If you have been using it since the Cache days, you may want to brush up on some of its changes.

In Cache 2018, the %Get method only had one argument. It was the key to retrieving from the JSON, meaning that if your JSON object called myObj, it would look like the following:

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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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Article
· Sep 11, 2024 9m read
Dates with InterSystems

Do not let the title of this article confuse you; we are not planning to take the InterSystems staff out to a fine Italian restaurant. Instead, this article will cover the principles of working with date and time data types in IRIS. When we use these data types, we should be aware of three different conversion issues:

  1. Converting between internal and ODBC formats.
  2. Converting between local time, UTC, and Posix time.
  3. Converting to and from various date display formats.

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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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Article
· May 20, 2017 10m read
Localization in Caché DBMS

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.

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Article
· Feb 26 6m read
The Case for IRIS and JavaScript

Introduction

My guess is that most IRIS developers create their applications using its native ObjectScript language or, if using an external language, then most likely using either Java, Python or perhaps C++.

I suspect that only a minority have considered using JavaScript as their language of choice, which, if true, is a great shame, because, In my opinion and experience, JavaScript is the closest equivalent to ObjectScript in terms of its ability to integrate with the IRIS's underlying multi-dimensional database.

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Earlier this year I announced availability of a VS Code extension for coding in ObjectScript, Embedded Python or SQL using the notebook paradigm popularized by Jupyter. Today I published a maintenance release to correct a "getting started" problem.

Here's a video of the installation steps from the extension's README:

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So I know it's been a while, and I hate to let my adoring fans down... just not enough to actually start writing again. But the wait is over and I'm back! Now bask in my beautiful ginger words!

For this series, I am going to look at some common problems we see in the WRC and discuss some common solutions. Of course, even if you find a solution here, you are always welcome to call in and expression you gratitude, or just hear my voice!

This week's common problem: "My query returns no data."

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Article
· Jul 26, 2019 3m read
Dynamic SQL to Dynamic Object

Hello community! I have to work with queries using all kinds of methods like embedded sql and class queries. But my favorite is dynamic sql, simply because of how easy it is to manipulate them at runtime. The downside to writing a lot of these is the maintenance of the code and interacting with the output in a meaningful way.

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Article
· Jul 7, 2017 19m read
Indexing of non-atomic attributes

Quotes (1NF/2NF/3NF)ru:

Every row-and-column intersection contains exactly one value from the applicable domain (and nothing else).
The same value can be atomic or non-atomic depending on the purpose of this value. For example, “4286” can be
  • atomic, if its denotes “a credit card’s PIN code” (if it’s broken down or reshuffled, it is of no use any longer)
  • non-atomic, if it’s just a “sequence of numbers” (the value still makes sense if broken down into several parts or reshuffled)

This article explores the standard methods of increasing the performance of SQL queries involving the following types of fields: string, date, simple list (in the $LB format), "list of <...>" and "array of <...>".

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InterSystems FAQ rubric

In the sample below, an image file is encoded into a Base64 string in a class property, saved, decoded again with Base64, and restored to another file.

【Usage class】

Class User.test Extends %Persistent
{
Property pics As %GlobalBinaryStream;
}


【When importing】

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The DeclarativeCOS project is a heartfelt cry about programming in the COS language.

The purpose of the project is to draw attention of the public to improving the inner core of COS.

The idea of the project is the support of a laconic syntax for cycles and collections.

So what is this laconic something that I have come up with? Welcome to the examples below!

Examples

The key concept underlying the project is the declarative approach to writing code. You need to specify WHAT should be used and HOW.

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Methods written in ObjectScript can use pass-by-reference arguments to return information to the caller. Python doesn’t support pass-by-reference arguments, so Embedded Python in IRIS doesn’t support them either. That's it, that's the end of the post, hope you liked it. 😉 But wait, what about the Classic Rock & Roll?

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This article was written as an attempt to share the experience of installing the InterSystems Caché DBMS for production environment.
We all know that the development configuration of a DBMS is very different from real-life conditions.
As a rule, development is carried out in “hothouse conditions” with a bare minimum of security measures, but when we publish our project online, we must ensure its reliable and uninterrupted operation in a very aggressive environment.

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Hi Developers!

Sometimes we need to import CSV data programmatically to InterSystems IRIS either from CSV or from URL. And we expect the class with proper datatypes to be created and the data to be imported.

I published a module csvgen on Open Exchange which does exactly that.

If you just need the CSV file be imported into IRIS you can do the following:

USER>do ##class(community.csvgen).Generate("/usr/data/titanic.csv",,"Data.Titanic")

Class name: Data.Titanic
Header: PassengerId INTEGER,Survived INTEGER,Pclass INTEGER,Name VARCHAR(250),Sex VARCHAR(250),Age INTEGER,SibSp INTEGER,Parch INTEGER,Ticket VARCHAR(250),Fare MONEY,Cabin VARCHAR(250),Embarked VARCHAR(250)
Records imported: 891
USER>

Or if you have the CSV on the internet, e.g. COVID-19 Data on Github you can get the data in the following way:

USER>d ##class(community.csvgen).GenerateFromURL("https://raw.githubusercontent.com/CSSEGISandData/COVID-19/master/csse_covid_19_data/csse_covid_19_daily_reports/05-29-2020.csv",",","Data.Covid19")

Class name: Data.Covid19
Header: FIPS INTEGER,Admin2 VARCHAR(250),Province_State VARCHAR(250),Country_Region VARCHAR(250),Last_Update DATE,Lat MONEY,Long_ DOUBLE,Confirmed INTEGER,Deaths INTEGER,Recovered INTEGER,Active INTEGER,Combined_Key VARCHAR(250),Incidence_Rate DOUBLE,Case-Fatality_Ratio DOUBLE
Records imported: 3522
USER>

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For some years I missed being able to offer, to everybody interested in ObjectScript, a tutorial more or less complete, to start with ObjectScript. Something that could help more and make things easier to those new developers that come to our technology... something intermediate, halfway between the common "Hello World!", that doesn't really get you further, and the "Advanced Training", that is unaffordable because of lack of time,etc.

If there were something truly helpful not only as an introduction to the ecosystem, but as a starting point, as a boost, to really start to walk into ObjectScript and move forward by yourself... wouldn't that be awesome?

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