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#Relational Tables

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Relational model organizes data into one or more tables (or "relations") of columns and rows, with a unique key identifying each row. Rows are also called records or tuples.

Learn more on relational data model.

InterSystems Data Platform (IDP) supports relational tables as part of the multi-model storage concept. IDP provides SQL and API access to relational tables.

Documentation.

Contestant

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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Hi, Community!

Want to improve accuracy and data integrity in your relational databases? Learn a key strategy in this video:

Setting Up SQL Foreign Key Constraints

https://www.youtube.com/embed/-kDpp6kq7Ns?utm_source=youtube&utm_medium=social&utm_campaign=-kDpp6kq7Ns
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Hello IRIS Community,

InterSystems Certification is developing a certification exam for InterSystems IRIS SQL specialists, and if you match the exam candidate description given below, we would like you to beta test the exam. The exam will be available for beta testing on June 9 - 12, 2024 at InterSystems Global Summit 2024, but only for Summit registrants (visit this page to learn more about Certification at GS24). Beta testing will open for all other interested beta testers on June 24, 2024. However, interested beta testers should sign up now by emailing certification@intersystems.com (please let us know if you will be beta testing at Global Summit or in our online proctored environment). The beta testing must be completed by August 2, 2024.

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Hi Community,

I am attempting to create a new table by executing a SELECT statement that involves joining multiple tables. However, I encountered an error during execution: '( expected, AS found^Combined AS.' I would also like to create a cube based on this SQL table. However, during the cube creation process, I am prompted to specify a source class, and I'm unsure which class to use as it requires an existing class. Could you please help me identify the issue with the table creation, and provide guidance on selecting the appropriate source class for the cube creation?"

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Article
· Aug 2, 2022 8m read
Data models in InterSystems IRIS

Before we start talking about databases and different data models that exist, first we'd better talk about what a database is and how to use it.

A database is an organized collection of data stored and accessed electronically. It is used to store and retrieve structured, semi-structured, or raw data which is often related to a theme or activity.

At the heart of every database lies at least one model used to describe its data. And depending on the model it is based on, a database may have slightly different characteristics and store different types of data.

To write, retrieve, modify, sort, transform or print the information from the database, a software called Database Management System (DBMS) is used.

The size, capacity, and performance of databases and their respective DBMS have increased by several orders of magnitude. It has been made possible by technological advances in various areas, such as processors, computer memory, computer storage, and computer networks. In general, the development of database technology can be divided into four generations based on the data models or structure: navigational, relational, object and post-relational.

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InterSystems IRIS currently limits classes to 999 properties.

But what to do if you need to store more data per object?

This article would answer this question (with the additional cameo of Community Python Gateway and how you can transfer wide datasets into Python).

The answer is very simple actually - InterSystems IRIS currently limits classes to 999 properties, but not to 999 primitives. The property in InterSystems IRIS can be an object with 999 properties and so on - the limit can be easily disregarded.

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Hello Everyone,

The Certification Team of InterSystems Learning Services is in the process of developing two exams focused on using SQL in InterSystems IRIS and we need input from our InterSystems IRIS SQL community. Your input will be used to evaluate and establish the contents of the exam.

How do I provide my input? We will present you with a list of job tasks, and you will rate them on their importance as well as other factors.

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This is the second piece in our series on 2021.2 SQL enhancements delivering an adaptive, high-performance SQL experience. In this article, we'll zoom in on the innovations in gathering Table Statistics, which are of course the primary input for the Run Time Plan Choice capability we described in the previous article.

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The 2021.2 release of the InterSystems IRIS Data Platform includes many exciting new features for fast, flexible and secure development of your mission-critical applications. Embedded Python definitely takes the limelight (and for good reason!), but in SQL we've also made a massive step forward towards a more adaptive engine that gathers detailed statistical information about your table data and exploits it to deliver the best query plans. In this brief series of articles, we'll take a closer at three elements that are new in 2021.2 and work together towards this goal, starting with Run Time Plan Choice.

It's hard to figure out the right order to talk about these (you can't imagine how often I've reshuffled them in writing this article!) because they fit together in such a nice way. As such, feel free to go on a limb and read these in random order smiley.

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This is the third article in our short series around innovations in IRIS SQL that deliver a more adaptive, high-performance experience for analysts and applications querying relational data on IRIS. It may be the last article in this series for 2021.2, but we have several more enhancements lined up in this area. In this article, we'll dig a little deeper into additional table statistics we're starting to gather in this release: Histograms

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In Cache WIndows environment:

Trying to use the $SYSTEM.SQL.DDLImport to import XML File that has ClassMethods, no SQL Table, but it doesn't appear to be working. I can use this ClassMethod to create SQL Tables. The manual method I have been using is to go into Cache Management Portal, Classes, Import.

I create an XML file first, then run the following to import but get no errors. Any ideas?

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Hi Cache team, I am in the need of listing all the user defined schemas that are present my Cache db and also the user defined tables and views and Columns of those tables and views through Queries. So that I can write some JDBC code to run the queries and fetch the above metadata. Any help is appreciated.

Thanks in Advance,

Kranthi kiran.

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I noticed when creating Record Map's within Ensemble that it is creating a Persistent cache table as it translates the file and puts it into the Record Map data structure.

I was wondering if there was a way to add a column to the cache table that is Hidden from the record map, but is a calculated date value on when that record was inserted?

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I know that 1-1 relationships are not officialy supported by intersystems cache/iris so I want to know the best way to store data with this kind of data model.

Currently I have two classes that where implemented some time ago:

Table A with a relationship type one on table B

Table B with a relationship type one on table A

To compile I have a double compile with qualifyer U.

What is the best way to implement a data model with 1-1 relationships?

Thank you

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A More Industrial-Looking Global Storage Scheme

In the first article in this series, we looked at the entity–attribute–value (EAV) model in relational databases, and took a look at the pros and cons of storing those entities, attributes and values in tables. We learned that, despite the benefits of this approach in terms of flexibility, there are some real disadvantages, in particular a basic mismatch between the logical structure of the data and its physical storage, which causes various difficulties.

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Introduction

In the first article in this series, we’ll take a look at the entity–attribute–value (EAV) model in relational databases to see how it’s used and what it’s good for. Then we'll compare the EAV model concepts to globals.

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In Episode 4 of Data Points, we welcome @Benjamin De Boe to the pod to discuss some of the things you can do to optimize your SQL queries in InterSystems IRIS. We've all heard — either from ourselves or from others — the "this runs too slowly" complaint. I thought Benjamin did a great job walking through many of the things within IRIS you can look at with your queries to see what can be improved.

https://5e18edf067eb59-03854285.castos.com/player/153376
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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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Globals, these magic swords for storing data, have been around for a while, but not many people can use them efficiently or know about this super-weapon altogether.

If you use globals for tasks where they truly shine, the results may be amazing, either in terms of increased performance or dramatic simplification of the overall solution (1, 2).

Globals offer a special way of storing and processing data, which is completely different from SQL tables. They were first introduced in 1966 in the M(UMPS) programming language, which was initially used in medical databases. It is still used in the same way, but has also been adopted by some other industries where reliability and high performance are top priorities: finance, trading, etc.

Later M(UMPS) evolved into Caché ObjectScript (COS). COS was developed by InterSystems as a superset of M. The original language is still accepted by developers' community and alive in a few implementations. There are several signs of activity around the web: MUMPS Google group, Mumps User's group), effective ISO Standard, etc.

Modern global based DBMS supports transactions, journaling, replication, partitioning. It means that they can be used for building modern, reliable and fast distributed systems.

Globals do not restrict you to the boundaries of the relational model. They give you the freedom of creating data structures optimized for particular tasks. For many applications reasonable use of globals can be a real silver bullet offering speeds that developers of conventional relational applications can only dream of.

Globals as a method of storing data can be used in many modern programming languages, both high- and low-level. Therefore, this article will focus specifically on globals and not the language they once came from.

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