Posts

I was doing some consulting recently and reviewing a developer’s code. I was surprised to find extensive use of global temporary tables. Let me start by saying this: global temporary tables are almost never what you should be using.

When I asked why he’d used them, he told me that he wanted the temporary tables that he created in his procedure, to be available to other procedures that were run from within the procedure. So in PROC-A, he was running PROC-B and PROC-C. A temporary table was created in PROC-A and he wanted to be able to use it in PROC-B and PROC-C.

2021-02-04

I have a deep interest in artificial intelligence and how it will change the world. I regularly present sessions on what I see coming, technology-wise. Many examples in those sessions are based on breakthroughs related to medicine. So I was pleased to get to listen to Eric Topol’s book Deep Medicine: How Artificial Intelligence Can Make Healthcare Human Again.

Eric spends time discussing how much of existing medicine is functional yet quite broken. Very few doctors now really connect with and relate to their patients. Worse, misdiagnoses are becoming far too frequent, arguably because of this disconnection.

2021-02-03

I’ve been working at a site that uses proxy servers for Internet access. And we were unable to clone a Git repository in Azure DevOps (AzDO) from within Visual Studio (VS). It was quite frustrating.

Visual Studio has got proxy settings and I had configured those:

They live in the system.net node within the settings.

VS was able to get out to the Internet, and I could find and try to connect to projects in AzDO but I couldn’t clone them from within there.

2021-02-02

Sometimes we need to determine whether a string is a date or whether it is a number.

In the first example above, I’m asking if the string ‘20190229’ is a valid date. You can see from the response (0) that it isn’t. That’s because even though it’s a valid date format, February in 2019 doesn’t have a 29th day. It’s not a leap year.

The value returned from the ISDATE function is a zero or a 1.  Curiously, the return value is of data type int. You’d think that a function that starts with Is and tests something would return a bit data type instead. But that’s just one of the curiosities of T-SQL.

2021-02-01

I’ve had a lot of good feedback about the options that we’ve provided in our free SDU Tools for developers and DBAs for formatting strings. Someone recently asked for a format with all capitals and dashes in between. I realised we didn’t have that, and we’ve added it. Generally, in the industry, this is referred to as Cobol Case.

So, we added a function CobolCase.

It takes one parameter:

@InputString - the string to be formatted

2021-01-29

Another book that I listened to recently, also fits into the “I nearly didn’t get past the first chapter” category. It was Atomic Habits by James Clear. By the end of this book though, I realised just how much I’d enjoyed it.

James makes a really interesting study into habits. Far more than anything I’d ever read before.

He makes it so clear how the compound effect of hundreds of small decisions leads to profound life changes. That was already pretty obvious to me but I loved the way he made this so practical. He calls the habits that are formed Atomic Habits.

2021-01-28

I recently recorded a podcast with Kamil Nowinsky. Kamil is well-known for creating some tools that make it easy to publish individual Azure Data Factory pipelines. It’s a far better method that the standard ARM (Azure Resource Manager) template deployment that’s provided by Microsoft.

However, if you use this method (and I recommend you do), you’ll be publishing pipelines separate to the linked services that your datasets connect to.

One mistake I’ve seen a few clients making lately, is that when they created the linked services in different environments, they did so with slightly different names. Because of that, they needed to modify the deployed objects after deployment. You don’t want to be doing that.

2021-01-27

We all use IN when writing queries:

SELECT ProductID, ProductName, Color, Size 
FROM dbo.Products 
WHERE Size IN ('370ml', '220ml');

A challenge comes up though, when you want to find pairs of values using IN. For example, if I have the following pairs of values:

Size        Color  370ml   Blue 370ml   Red 220ml   Blue

How do I find those when using IN?

Other databases do allow you to have pairs:

SELECT ProductID, ProductName, Color, Size
FROM dbo.Products 
WHERE (Size, Color) 
    IN (('370ml', 'Blue'), ('370ml', 'Red'), ('220ml', 'Blue'));

I wish T-SQL had that option but it doesn’t. It would be particularly useful when those values in the IN clause are coming from a sub-query.

2021-01-26

If you are using a string that was provided by another system, it might not be in the format that you were hoping it would be. So for example, if I have this string that says 2/29/2016, I know that’s a US date format, but if it was only 5/4/2016, there’s no way I could just easily tell that.

Conversion functions use your session settings to determine how to convert the values. When I’m converting strings to dates (and/or times), I certainly don’t want to change my settings so that I run with US configuration.

2021-01-25

I spend a lot of time doing data conversion work. It’s hard to imagine how much of that relates to working with dates and times. A requirement that I had recently was to find the nearest weekday to a given date i.e. find me the closest Thursday to a supplied date.

The NearestWeekday function in our free SDU Tools for developers and DBAs, does this.

It takes two parameters:

@TargetDate date - the date that we’re aiming for @DayOfWeek int - Sunday = 1, Monday = 2, Tuesday = 3, etc. (values from 1 to 7)

2021-01-22