Hi,

My doubt is about the SQL Query in Caché:

I don't want to take all results from the table and orgainze them manually, for example: I have a table with 50 records, but I only want to select 10 records, being from tenth until the twentieth and this without knowing their IDs.

So, how can I do this, without losing performance, there is any way?

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Hi,

I have a situation where I write a character stream to a file. The file content gets signed and the signature is sent to a service provider together with the file content.

The signing is done using openssl.

This works perfectly on a dev PC, which is runnning Windows and has a little-endian architecture.

The problem is as soon as I do this on the server, which has a big-endian architecture, the signed value is incorrect according to the service provider.

The content is signed using RSA SHA256 with PSS padding.

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$LIST string format and %DynamicArray and %DynamicObject classes

IRIS, and previously Cache, contain several different ways to create a sequence containing a mixture of data values. A data sequence that has been available for many years is the $LIST string. Another more recent data sequence is the %DynamicArray class, which along with the %DynamicObject class, is part of the IRIS support for JSON string representation. These two sequences involve very different tradeoffs.

$LIST String Format

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Article
· May 20, 2016 12m read
Collations in Caché

Order is a necessity for everyone, but not everyone understands it in the same way
(Fausto Cercignani)

Disclaimer: This article uses Russian language and Cyrillic alphabet as examples, but is relevant for anyone who uses Caché in a non-English locale.
Please note that this article refers mostly to NLS collations, which are different than SQL collations. SQL collations (such as SQLUPPER, SQLSTRING, EXACT which means no collation, TRUNCATE, etc.) are actual functions that are explicitly applied to some values, and whose results are sometimes explicitly stored in the global subscripts. When stored in subscripts, these values would naturally follow the NLS collation in effect (“SQL and NLS Collations”).

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Have some free text fields in your application that you wish you could search efficiently? Tried using some methods before but found out that they just cannot match the performance needs of your customers? Do I have one weird trick that will solve all your problems? Don’t you already know!? All I do is bring great solutions to your performance pitfalls!

As usual, if you want the TL;DR (too long; didn’t read) version, skip to the end. Just know you are hurting my feelings.

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Hi, Community!

Have a question for general discussion.

In ObjectScript we have cls for classes and mac code, which both compile into int code.

Is there any reason when you use mac instead of cls for non-persistent classes?

For me the benefits for cls are:

1. Inheritance and other OOP features

2. Auto-documented code

For mac one visible benefit is easier call in terminal:

do method^Utils(p1,p2)

vs

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Hope most of you already familiar with project CachéQuality from @Daniel Tamajon. For those who don’t know about it, it is a static syntax analyzer for your code written for InterSystems products. It may help you to find and solve many different types of issues in your code, and even possible bugs before clients will find it in production. So, with help of CachéQuality you will be able to deliver a better product. You can find the complete list of rules used to check ObjectScript code here.

It was already available in Studio. And now it is also available in VSCode.

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Cache tricks

Several years ago, long before Developer Community Portal was launched, I published a series of Caché tricks at one of Czech web sites. In this article, I’m posting translated version of one of them.

Capturing output of someone else’s methods or routines

Suppose you, or someone else created a useful method or routine, that was producing some computation that you’d like to benefit from, but the routine was writing output to process principal device.

You would like to use the data, but you need it not written to a device, but assigned to a variable. And, for any reason, you can’t modify the code. What can you do?

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Way back when during our Siemens LCR days we had to limit the number of characters in OBX.5 to a length of 75. That was back when we had eGate.

Now I need to do the reversal of that and take loop through a string length and split the string up into multiple OBX or NTE based on a certain length. In reading documentation $EXTRACT can do this if you know the exact length, but in this case we don't.

So how would one loop through a string and say every 75 characters create a new OBX or NTE segment?

Thanks

Scott

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Some time ago I got a WRC case transferred where a customer asks for the availability of a raw DEFLATE compression/decompression function built-in Caché.

When we talk about DEFLATE we need to talk about Zlib as well, since Zlib is the de-facto standard free compression/decompression library developed in the mid-90s.

Zlib works on particular DEFLATE compression/decompression algorithm and the idea of encapsulation within a wrapper (gzip, zlib, etc.).
https://en.wikipedia.org/wiki/Zlib

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The .NET Core Identity model has an IPasswordHasher<> interface for for

  • Hashing a password so that it can be stored in a database
  • Verifying a provided plain-text password matches a previously stored hash.

I am getting invalid password errors during the login process when the .NET Core Identity model computes a hash from a plain text input and compares it to a password hash value I've returned from Caché. The default hashing algorithm is PBKDF2 with HMAC-SHA256, 128-bit salt, 256-bit subkey, and 10,000 iterations (detailed article on .NET Core Identity PasswordHasher). The algorithm Caché uses is probably different which may be why I am getting errors.

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Hi everyone,

I am still learning the platform for a student project and have to do some streaming and data analysis next. Since for my case I have no "live api" I wanted to just stream json files and output the data as it comes in from the files. (basically to emulate a incoming data scenario)

So thanks to the documentation and community posts I have figured how to create a stream and read data from a JSON but since I'm also new to JSON I have some parsing problems. I don't know how to access subarrays/sub-objects via objectscript.

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Hello,

Can anyone please provide me with a guide I can follow to create an entry in Cache's SSL/TLS configuration that would allow me to "speak" to an website via the Post method using SSL.

I need to simulate functionality that is provided by my browser but from with Cache.

The topics I have are:

1. From where do I source the certificate that will be used for this process?

2. What processing must I do on it to make it acceptable for Cache's SSL/TLS

3. What settings are required when filling the the form

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Hi Developers!

Many of you publish your InterSystems ObjectScript libraries on Open Exchange and Github.

But what do you do to ease the usage and collaboration to your project for developers?

In this article, I want to introduce the way how to introduce an easy way to launch and contribute to any ObjectScript project just by copying a standard set of files to your repository.

Let's go!

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Does anyone have any experience with getting, unfortunately, an older version of Cache to authenticate via SMTP to send email? I have verified that the settings are set up properly on the mailbox as I have successfully sent an email from a LAMP server, which comes from the same IP address.

If you have any thoughts, I would greatly appreciate it.

This is the error I receive

ERROR #6034: SMTP server connection failed during MAIL FROM command: <READ>zSend+105^%Net.SMTP.1.

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I have an OAuth 2.0 development environment where Caché is serving all three roles as the Authorization Server, Client and Resource Server based on a great 3-part series on OAuth 2.0 by @Daniel Kutac. I have a simple password grant type where an x-www-form-urlencoded body (as described in this post) is sent as a POST to the token endpoint at https://localhost:57773/oauth2/token and a response body with a HTTP Response 200 header is returned. The response body looks something like this.

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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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*** archived ***

The question has come up several times and I saw mixed answers and no quick example

My personal preference is using CPIPE device as you get back exactly the output you will get at the command line interface of your OS .
The tricky thing is to stop reading in time.
The example just displays what you normally see in your console.
it becomes useful if you look for things that you can't get from any $system.whatever()

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Hi everyone,

I'm having trouble parsing XML containing unicode characters which I receive from an external webservice. I believe my file is saved properly with UTF-8 encoding but the SAX Parser still throws me an error.

I have 2 classmethods: 1 general one (get) to make a request to a webservice and return the date, and 1 (getSportsPerDate) to make a specific call and then parse the data.

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