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#SQL

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SQL is a standard language for storing, manipulating and retrieving data in relational databases.

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 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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What I find really useful about IRIS when teaching my subject of Postrelational databases is the fact that it is a multi model database. Which means that I can actually go into architecture and structure and all that only once but then show the usage of different models (like object, document, hierarchy) using the same language and approach. And it is not a huge leap to go from an object oriented programming language (like C#, Java etc) to an object oriented database.

However, along with advantages (which are many) come some drawbacks when we switch from object oriented model to relational. When I say that you can get access to the same data using different models I need to also explain how it is possible to work with lists and arrays from object model in relational table. With arrays it is very simple - by default they are represented as separate tables and that's the end of it. With lists - it's harder because by default it's a string. But one still wants to do something about it without damaging the structure and making this list unreadable in the object model.

So in this article I will showcase a couple of predicates and a function that are useful when working with lists, and not just as fields.

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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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An interesting pattern around unique indices came up recently (in internal discussion re: isc.rest) and I'd like to highlight it for the community.

As a motivating use case: suppose you have a class representing a tree, where each node also has a name, and we want nodes to be unique by name and parent node. We want each root node to have a unique name too. A natural implementation would be:

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Introduction

InterSystems IRIS allows you to build REST APIs using ObjectScript classes and the %CSP.REST framework. This enables the development of modern services to expose data for web apps, mobile apps, or system integrations.

In this article, you'll learn how to create a basic REST API in InterSystems IRIS, including:

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This article describes a significant enhancement of how InterSystems IRIS deals with table statistics, a crucial element for IRIS SQL processing, in the 2025.2 release. We'll start with a brief refresher on what table statistics are, how they are used, and why we needed this enhancement. Then, we'll dive into the details of the new infrastructure for collecting and saving table statistics, after which we'll zoom in onto what the change means in practice for your applications. We'll end with a few additional notes on patterns enabled by the new model, and look forward to the follow-on phases of this initial delivery.

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Hi Community,

Enjoy the new video on InterSystems Developers YouTube from our Tech Video Challenge:

⏯ Using Character Slice Index in InterSystems IRIS

https://www.youtube.com/embed/_aYpLVZfiCA
[This is an embedded link, but you cannot view embedded content directly on the site because you have declined the cookies necessary to access it. To view embedded content, you would need to accept all cookies in your Cookies Settings]

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Hello IRIS community,

InterSystems Certification is currently developing a certification exam for InterSystems IRIS SQL professionals, 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 starting May 19, 2025.

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Hello, good morning, thank you so much for reading this question. ☺️🙂👍

We are developing a code to get information about our Production's items: services, processes and operations.

We know we can get various configurations of a given item: Category, Port, Enabled...

But we wonder how we could get the date time of the last mesage (most recent) received in an item.

To give a code snippet a small section of the code we have developed (and tested), it looks like:

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How do I write DDL script for collection properties?

For example I want to create the following class:

Class SQLUser.Person {

Property Name As %String;

Property FavoriteColors As list Of %String;

}

My DDL script looks like this:

CREATE TABLE Person (Name varchar(50), FavoriteColors ???)
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If you're migrating from Oracle to InterSystems IRIS—like many of my customers—you may run into Oracle-specific SQL patterns that need translation.

Take this example:

SELECT (TO_DATE('2023-05-12','YYYY-MM-DD') - LEVEL + 1) AS gap_date
FROM dual
CONNECT BY LEVEL <= (TO_DATE('2023-05-12','YYYY-MM-DD') - TO_DATE('2023-05-02','YYYY-MM-DD') + 1);

In Oracle:

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Does anyone have a query that I could run to show a Vendor the time difference between when a message was sent out a BO, and when we received the HL7 ACK back that is associated with the message sent?

I am trying to prove to this vendor of the delay we are seeing getting the ACK back because of a Timeout

I know how to pull Ens.MessageHeader, and EnsLib.HL7.Message but not sure how to match up the Message with the HL7 Acknowledgement received.

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Hi community.

I was wondering if it was possible to use something like EnsLib.SQL.InboundAdapter with tables in IRIS.

This library monitors when a record has been inserted into a table in an external database, so it requires a DSN to connect to that database.

My goal is to make a call to an external API that takes a long time, it could spend nearly an hour (or more) completing its processes, but I don't want to block the main process.

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I am testing vectorsearch, while doing so I am trying to paginate my resultset for a "next page" function to give me the first, second, third 15 entries within a table.

For this I have two embedding classes. One with a HNSW Index (vectornomicembedtextlatest) , and one without (vectornomicembedtexttest).

Calling SELECT ID,PRIMKEY FROM SQLUser.vectornomicembedtexttest LIMIT 5 OFFSET 1 works fine with the first entry having the rowID of 486448. (I deleted old entries in the beginning and reused the table)

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With the release of InterSystems IRIS Cloud SQL, we're getting more frequent questions about how to establish secure connections over JDBC and other driver technologies. While we have nice summary and detailed documentation on the driver technologies themselves, our documentation does not go as far to describe individual client tools, such as our personal favourite DBeaver. In this article, we'll describe the steps to create a secure connection from DBeaver to your Cloud SQL deployment.

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Hi, I am unsure how to remove this restriction; when I am performing dynamic SQL using ##class(%SQL.Statement).%ExecDirectNoPriv(, .query, args...)

It works fine, but the moment I add specific properties from the persistent class I am performing the select on into the WHERE clause, I get: ERROR #5540: SQLCODE: -99 Message: User UnknownUser is not privileged for the operation. Despite using %ExecDirectNoPriv, I've tried with prepared statement as well, exact same situation.

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