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Month: October 2023

Two Takes on First Normal Form

Published 2023-10-11 by Kevin Feasel

Joe Celko defends the honor of First Normal Form:

You do not need a complete understanding of regular expressions or ICD codes to follow this article, so don’t worry too much about it. The reason for posting the simplified regular expression was to scare you. My point was that this regular expression would be a pretty impressive CHECK constraint on this column. Shall we be honest? Despite the fact that we know the best programming practice is to detect an error as soon as possible, do you believe that the original poster wrote such a constraint for the concatenated list of ICD codes?

I’m willing to bet that any such validation is being done in an input tier by some poor lonely program, in an application language. Even more likely, it’s not being done at all.

First Normal Form (1NF) says that this concatenated string is a repeated group, and we need to replace it with a proper relational construct.

In the meantime, I’ve continued my series on database normalization and call First Normal Form overrated:

In this video, we start at the ground floor with 1st Normal Form. We’ll learn what people think it is, what it really is, and why it’s not as great as it’s cracked up to be.

I agree with Joe that his ICD-10 code example is a bad database design. The area in which I don’t agree—and for this, I’m leaning heavily on C.J. Date—is that repeating groups actually violate 1NF. My video covers this in a bit more detail and I also include a quotation from Date’s recent book on database design talking about how 1NF has nothing to do with repeating groups or atomicity, and that 1NF could even include relvars inside of relvars (an example Joe shows 1NF preventing).

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Hybrid Failover Rights from SQL Server 2022 to Azure SQL MI

Published 2023-10-11 by Kevin Feasel

Dani Ljepava explains a new benefit:

Hybrid failover rights is a new benefit that allows you to run a license-free Azure SQL Managed Instance when used as a passive DR replica for your SQL Server 2022 licensed under Software Assurance (SA), or using Pay-as-you-go billing option.

How the Hybrid Failover Rights benefit works

The new Hybrid failover rights licensing benefit is technology agnostic. You can use any technology, such is MI link as the most advanced replication technology using Always On, or perhaps LRS, ADF, transactional replication, backup and restore, or similar to setup replication between SQL Server and Managed Instance. As long as you are using Azure SQL Managed Instance only as a passive replica for your SQL Server 2022, you are eligible to apply the new licensing benefit.

Read on for more details on how you can activate this benefit.

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Against Transparent Data Encryption in SQL Server

Published 2023-10-11 by Kevin Feasel

Andy Yun is not a fan:

Of all of the various data protection options available to us in SQL Server, I argue that Transparent Data Encryption (aka TDE) is worthless Security Theater.

TDE encrypts your data files “at rest.” This means one cannot crack open a hex editor and just start reading your raw data. And did you know that you can use a hex editor and start reading string values right out of your MDF files? Go search on that – that’s a separate tangent you can go explore.

Read on to understand the ways in which Andy finds fault with TDE.

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A Starting Point for Data Protection

Published 2023-10-11 by Kevin Feasel

Deborah Melkin asks some questions:

If we start expanding things beyond just the technology and functionality, we can really see where the concept of data protection becomes much larger and more complex.

I admit that I’m not really up-to-speed on the technical aspects of encryption or data protection. That doesn’t fall under a lot of the work that I do. But there’s another side to data protection that’s worth talking about. It’s about knowing your data. This is where I’ve been spending a lot of my time these days.

When I ask if you know your data, I’m asking if you can answer the following questions:

Read on for some of the types of questions you’ll want to think about.

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An Overview of Transparent Data Encryption

Published 2023-10-11 by Kevin Feasel

Chad Callihan looks at one option for securing a SQL Server instance:

This month’s T-SQL Tuesday topic comes from Matthew McGiffen, who asks us to talk about encryption and protecting data in SQL Server. To read the full topic invite, click the T-SQL Tuesday logo to the right.

For this month’s invite, I thought I’d write about Transparent Data Encryption (TDE) and give a reminder about how it relates to tempdb.

Read on for Chad’s reminder.

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Bionic Reading in R

Published 2023-10-10 by Kevin Feasel

Tomaz Kastrun says reading is fundamental:

Trick your brain into faster reading with the help of Bionic Reading. With the help of highlighting part of the words, it “guides your eyes over the text and the brain remembers previously learned words more quickly.” (source: br-about)

Here is a beautiful example of how text with the use of opacity, colours, size and many other elements can be quickly achieved for faster reading.

Click through for an example and how to implement it in R.

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A Path to Avoid Getting Overwhelmed with Microsoft Fabric

Published 2023-10-10 by Kevin Feasel

Kurt Buhler tries to limit information overload:

It’s just too much; I don’t have time for all this stuff.

I think this is a big problem. It’s a problem not just because people shouldn’t feel overwhelmed, but also because it says something about how effectively these new features, tools, and resources are being communicated, understood, and used. But what is the problem, exactly? And if you’re in the minority of people not feeling overwhelmed, why should you care?

Perhaps most importantly, how can we approach these new features, tools, and resources to ensure we understand them and can find value without feeling overwhelmed?

Read on for several tips on how to tackle learning about a product with a large surface area. And I’d also note that anybody who is comfortable working in SQL Server had to go through the same process.

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The Internals of Backup Compression

Published 2023-10-10 by Kevin Feasel

Andy Yun continues a series on how backups work in SQL Server:

Welcome back to Part 4 of my Backup Internals series. Today, I’d like to spend a little time exploring backup compression.

When you take a regular FULL BACKUP, SQL Server is literally taking a byte-for-byte copy of your data files. Don’t believe me? Then go read this, then come back. Additionally, Microsoft architected BACKUP operations such that the resource utilization and impact would be minimal (when using default parameters).

This post taught me a few things about the practical impact of enabling compression. Even after reading this, however, I would almost always enable it for two reasons. First, storage is usually the bottleneck for organizations, so actions which reduce storage utilization can improve overall performance. Second, there are limits to how much we can store, so compressing backups may let me get away with holding more backups on a given LUN or drive.

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An Overview of Encryption Options in SQL Server

Published 2023-10-10 by Kevin Feasel

Rob Farley has a cipher:

Encryption is a funny thing. Since the dawn of communication, whenever people have wanted to keep their secrets secret, they’ve used some sort of encryption. I’m sure parents started spelling things so their kids wouldn’t understand as soon as there was spelling. Using words their kids wouldn’t understand, while the kid sits there thinking “Oh, Dad, you’re so embarrassing, thinking I don’t know what that means…”. Encryption is all about keeping information away from people, particularly those who could use it against you. Ask the folk from Bletchley Park if you don’t realise how this can impact world events.

Rob links to Enigma and Bomba (the British system for decrypting Enigma messages) but there’s another interesting story out of Bletchley Park as well: the Lorenz cipher, which was cracked by a Polish mathematician early on, but decryption was quite slow, on the order of a message or so per day. This led to Colossus, the first digital computer in existence. The National Museum of Computing in Bletchley Park has a working rebuild of a Mark 2 Colossus on display and we got to see it (and get the story behind it) on day 1 of Data Relay this year, so that was fun to see.

As an interesting side note, the British never told the Soviets that they had decrypted the Lorenz cipher, so when the Soviets took hold of these machines near the end of World War II, they assumed that nobody had cracked the code, so they continued to use these for a while, allowing the British access to certain sensitive communications for a time.

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