#Object Data Model

Here you have an easy way to write and execute COS code from your unix scripts. This way one does not need to write routines or even open Studio or Atelier. It can be an option for simple and small actions for instance things like installation tasks or compiling.

See sample bash script (compile.sh) to compile classes:

I'm participating in the Developing with InterSystems Objects and SQL with Joel Solon. The course is very nice and I will share with you some tips I got during the training. Tips presented in the day 3:

Hi,

this is a public announcement for the first release of Intersystems Cache Object-Relational Mapper in Python 3. Project's main repository is located at Github (healiseu/IntersystemsCacheORM).

About the project

CacheORM module is an enhanced OOP porting of Intersystems Cache-Python binding. There are three classes implemented:

• CacheClient This is the super class of CachePython module. It wraps two functions from intersys.pythonbind module pythonbind3.connection() and pythonbind3.database().

• CacheQuery A subclass of CacheClient that wraps methods and adds extra functionality in intersys.pythonbind.databaseand intersys.pythonbind.query classes

• CacheClass A subclass of CacheClient, that wraps methods and adds extra functionality in intersys.pythonbind.databaseand intersys.pythonbind.object classes

The intersys.pythonbind package is a Python C extension that provides Python application with transparent connectivity to the objects stored in the Caché database.

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.

Attached code contains a very basic $system.WorkMgr example.

It uses several jobs (workers) to update different chunks of rows of a table.

Steps:

• Creates a table with 100 records.
• Split table in chunks
• Initialize WorkMgr and queue chunks to workers.
  • Every worker simply sets its process number in the Job field of the processed row.

In this case, I have tested the example in a 8-core laptop:

Object Synchronization is a feature that has been around for a while, since Caché days, but I wanted to explore a bit more how it works. I've always thought that database automatic synchronization is complex by nature but, for some particular scenarios shouldn't be so hard. So I considered a very simple use case (OK, perhaps the typical one, I'm not discovering anything... but if it's common and it works, it's good ).

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.

When developing or maintaining Caché Objects applications, or even ones written in plain COS code, it's sometimes useful to investigate dependencies. Yuzinji is a tool that analyzes the Caché class dictionary plus the COS code within methods and routines, then feeds its results into Structure101g Studio.

Headache-free stored objects: a simple example of working with InterSystems Caché objects in ObjectScript and Python

Neuschwanstein Castle

Tabular data storages based on what is formally known as the relational data model will be celebrating their 50th anniversary in June 2020. Here is an official document – that very famous article. Many thanks for it to Doctor Edgar Frank Codd. By the way, the relational data model is on the list of the most important global innovations of the past 100 years published by Forbes.

On the other hand, oddly enough, Codd viewed relational databases and SQL as a distorted implementation of his theory. For general guidance, he created 12 rules that any relational database management system must comply with (there are actually 13 rules). Honestly speaking, there is zero DBMS's on the market that observes at least Rule 0. Therefore, no one can call their DBMS 100% relational :) If you know any exceptions, please let me know.

This is a sample to use %JSON.Adaptor class available in IRIS to produce a snapshot of your object.

The sample consists of 2 classes that are variations of what was known in Caché/SAMPLES as Sample.Person.
Be aware that the possibilities are limited by %JSON.Adapter and how you make use of it.

Once in place, you create some test data by Populate().
You select an object and take a snapshot.
You apply changes to your object and take another snapshot.
And see the difference.

BINGO!

The attached file contains an example of code generation using ObjectGenerators which builds a very simple homemade RuleEngine.

Code generation is an excellent way of increasing performance moving run-time calculations to compile-time.

We could generate code creating routines or implemeting methods using ObjectGenerators. In this example we are using ObjectGenerators.

Update: Rule Engine is now on GitHub https://github.com/intersystems-ib/cache-iat-ruleengine

Here's one way to determine if a class is mapped (i.e. it is in a package whose definitions come from a database other than the default code database for the current namespace):

SAMPLES>w ##class(%Library.RoutineMgr).IsMapped("Cinema.Film.cls")
0
SAMPLES>w ##class(%Library.RoutineMgr).IsMapped("%iKnow.Objects.Source.cls")
1
SAMPLES>

If you pass a by-ref second argument to IsMapped you can also discover what database the class definition is stored in:

Columnar storage is one of the newer offers provided by InterSystems IRIS. Unlike traditional row-based storage, it optimizes query processing by storing data in columns rather than rows, enabling faster access and retrieval of relevant information.

A couple of articles have been written on when it should be used to give a system the biggest boost, how to create tables like that using SQL

CREATE TABLE table (column1 type1, column2 type2, column3 type3) WITH STORAGETYPE = COLUMNAR  -- ex 1
CREATE TABLE table (column1 type1, column2 type2, column3 type3 WITH STORAGETYPE = COLUMNAR)  -- ex 2

and even the performance tests.

As we all know, InterSystems IRIS is a multi-model DBMS and it gives seamless access to the same data using relational and object access. So the former is covered in other articles, but what about the latter?

A benefit of using Doxygenerate is that Doxygen does more than just HTML output. Tweak the Doxyfile that tells Doxygen what to do and you can easily create a PDF. Our example MARINA application yielded a 524-page PDF. Here's what page 94 looks like:

You can browse the whole file here.