Sql-Server

One of my more surprisingly popular blog posts in the past talked about Machine Learning: Testing your installation of R and Python in SQL Server 2017. The problem is that SQL Server 2022 changed things.

Now the SQL Server team has published an article on how to make it work.  What I’ve been finding though, is that people are struggling to follow that article. And more concerning, people using named instances of SQL Server (like SQLEXPRESS) couldn’t get it to work at all, no matter how much they tried.

2024-03-04

This is the final part of a series on using Change Data Capture with Azure SQL Database, and looks at accessing the data from change data capture from another database.

Scenario

I often use Azure SQL Database as a data warehouse. It’s a perfectly fine database for that. But the challenge with Azure SQL Database is always about how to access data in other databases.

Many people don’t seem to realize that you can use External Tables (and External Data Sources) to read data in one Azure SQL Database, in another Azure SQL Database.

2024-01-22

The latest online on-demand course that I’ve been working on is now out the door. SQL Server Locking, Blocking, and Deadlocks for Developers and DBAs is available at our site: SQL Server Locking, Blocking and Deadlocks for Developers and DBAs (sqldownunder.com)

It’s designed to let you learn to find and fix locking issues, and to avoid them in the first place.

To celebrate the release, use coupon code LOCKINGRELEASE until January 20th to get 25% off the price.

2023-12-31

I know it’s been a while, but there’s a new SQL Down Under show published!

While I’ve been busy with https://cosmosdownunder.com and https://fabricdownunder.com , I haven’t forgotten the SQL Down Under shows. It’s time for some more SQL Server love.

I had the great pleasure yesterday to record a podcast with one of my UK based friends Rob Sewell. Rob’s one of the rare breed that is both a Data Platform MVP and an Azure MVP.

2023-11-11

In a previous post, I wrote about how to create a hash of all the columns in a table, by using FOR JSON PATH and HASHBYTES. This is incredibly useful if you need to check if incoming data is different to existing table data.

The code that I suggested (based on WideWorldImporters) was as follows:

SELECT po.PurchaseOrderID,
       HASHBYTES('SHA2_256', pod.PurchaseOrderData) AS HashedData
FROM Purchasing.PurchaseOrders AS po
CROSS APPLY
(
    SELECT po.*
    FOR JSON PATH, ROOT('Purchase Order'), INCLUDE_NULL_VALUES
) AS pod(PurchaseOrderData);

The challenge with that code though, is that for the existing table data, it’s best calculated when the data is stored, rather than every time it’s queried. And, bonus points if you then create an index that holds just the key for matching plus an included column for the HashedData. With a bit of careful work, you can get an efficient join happening to find differences.

2023-10-09

This is part 4 of a series on working with change data capture (CDC) in Azure SQL Database. This part discusses how to enable it and how to use it.

When I was reading the documentation for CDC in Azure SQL Database, I kept coming across a mention that it required at least an S3 service level objective (SLO), if you were using a DTU-based database.

I really hoped that wasn’t the case.

2023-09-23

I had an email from a friend today where he asked what was wrong with SQL Server, and wondered if ROUND() didn’t go to the same school that he did.

The example was:

SELECT '0.5' [SOURCE VALUE], '1' [SHOULD ROUND TO], ROUND('0.5',0) [SQL SAYS]
UNION
SELECT '1.55', '1.6', ROUND('1.55',1)
UNION
SELECT '94.55', '94.6', ROUND('94.55',1);

The output was:

What was puzzling him is why SQL Server’s ROUND was converting 94.55 to 94.5 and not 94.6. Now writing numbers as strings is problematic to start with, but that aside, he was puzzled by the output.

2023-07-11

I’ve previously posted about the procedure ListUseOfDeprecatedDataTypes in our free SDU Tools for developers and DBAs. I mentioned that I’m often reviewing existing databases and one of the first things I go looking for is the way they’ve used data types, and that in particular, I’m keen to know if they’ve used any deprecated data types (i.e. ones that will/might be removed at some point).

The procedure was updated in version 21 to now include a ChangeScript column. (Thanks to Michael Miller for the suggestion).

2023-06-02

This is part 3 of a series on working with change data capture (CDC) in Azure SQL Database. This part discusses how to enable it and how to use it.

To show how this works, I have created an Azure SQL Database called CDCTest. I created it as a DTU-based database with a service level objective (SLO) of S3. I’ll discuss more about the licensing implications of CDC in part 4.

2023-06-02

We have so many great tech friends in Poland. I was pleased to see they are running the MS Tech Summit, and pleased to be speaking at it.

Looks like a great set of sessions : https://mstechsummit.pl/en/ They tell me there are more than 100 sessions spread over 8 tracks.

Not in Poland? Not a problem. It’s running in-person and online, and with video on demand.

The early bird discount is still available but about to end.

2023-04-28