Sql-Server

A few days ago, I wrote about SQL CLR and how I don’t normally use it now, but if I did, which types of objects make sense for it. I briefly mentioned user-defined data types but today, I wanted to call out another limitation of these that I’d like to see addressed (if we keep on using SQL CLR).

Early versions of the user-defined data types in SQL CLR had a limitation on size, where they needed to be serializable within 8KB. That limit is now long gone and so the ability to define new data types using SQL CLR integration was now almost at a usable level, apart from one key omission: indexes.

2026-05-06

It was great to catch up with Jess Pomfret today and to have her on a SQL Down Under podcast.

Jess is a Data Platform Engineer and a dual Microsoft MVP. She started working with SQL Server in 2011, and she says she enjoys the problem-solving aspects of automating processes with PowerShell.

Jess also enjoys contributing to dbatools and dbachecks, two open source PowerShell modules that aid DBAs with automating the management of SQL Server instances.

2026-05-05

I’ve recently been talking to clients about SQL CLR objects. When these were first introduced in SQL Server 2005, many of us had high hopes for them. SQL Server has never been great in regard to extensibility and this provided some way to extend the product.

Nowadays, I avoid SQL CLR. And that’s a real pity. But it’s no longer supported in Azure SQL Database, apart from the system CLR objects of geometry, geography, and hierarchyid. (Note: I’m also not a fan of hierarchyid). I need to use extensibility methods that are available in the different environments that I work in, and Azure SQL Database is one of those. The same applies to Fabric SQL Database.

2026-05-04

Increasingly, developers are using tools that try to automate code generation when dealing with databases. Stored procedures have been a thorn in the side of this. Mostly that’s because it’s difficult to obtain the metadata that is really needed.

You should not need to be able to read the code of a stored procedure to know how to use it. And that includes the common exceptions it might throw. None of the existing tools for dealing with this currently do what’s needed.

2026-04-30

On a client site some years back, I came across a situation (unfortunately too common) where a column in a table was being used for two purposes. It could either hold an integer value or a string. Only about 100 rows out of many millions had the integer value. Some of the client code needed to calculate the maximum value when it was an integer. First step I tried was to add a persisted calculated column like so:

2026-04-24

I fell for this one this week. If you execute the following code in SQLCMD mode, what would you expect the output to be?

:SETVAR PrincipalServer WINSERVERBASE
:SETVAR MirrorServer WINSERVERBASE\\SQLDEV02
:SETVAR WitnessServer WINSERVERBASE\\SQLDEV03

:CONNECT $(PrincipalServer)
SELECT @@SERVERNAME;

:CONNECT $(MirrorServer)
SELECT @@SERVERNAME;

:CONNECT $(WitnessServer)
SELECT @@SERVERNAME;

I’m guessing you might not have expected:

WINSERVERBASE\SQLDEV03

WINSERVERBASE\SQLDEV03

WINSERVERBASE\SQLDEV03

The problem is the lack of a batch separator. What I should have written was this:

:SETVAR PrincipalServer WINSERVERBASE
:SETVAR MirrorServer WINSERVERBASE\\SQLDEV02
:SETVAR WitnessServer WINSERVERBASE\\SQLDEV03

:CONNECT $(PrincipalServer)
SELECT @@SERVERNAME;
GO

:CONNECT $(MirrorServer)
SELECT @@SERVERNAME;
GO

:CONNECT $(WitnessServer)
SELECT @@SERVERNAME;
GO

While this may be strictly correct, I can’t imagine it’s the behaviour anyone would wish for. Do you think that a :CONNECT statement in a SQLCMD batch should also be treated as a batch separator? Does it ever make sense for it not to?

2026-04-22

I often work with reports either in SQL Server Reporting Services (SSRS or now Power BI Reporting Services) and Fabric Paginated Reports. At a site this week, the complexity of the reports we were working on reminded me that I really, really don’t like seeing T-SQL code (or really any complex business logic) embedded in reports.

Don’t make refactoring difficult or impossible

DBAs tend to be considered a conservative bunch. One thing they’re usually conservative about is refactoring their databases. In many cases, this is because they have little idea what they will break when they make database changes.

2026-04-18

This is a post in the SQL Interview series. These aren’t trick or gotcha questions, they’re just questions designed to scope out a candidate’s knowledge around SQL Server and Azure SQL Database.

Section: Administration Level: Advanced

Question:

You have a SQL Server server attached to multiple storage volumes. One of the volumes has been lost. It contained the files for the tempdb database.

You know that tempdb is recreated on each restart of SQL Server, but will SQL Server still start when the files are missing? Will it just automatically create new files? If not, how could you work around it?

2026-04-14

Most SQL Server developers are aware that the EXEC statement can be used to:

• Execute a stored procedure (system, user-defined, extended)
• Execute some dynamic SQL

And most understand that you can SELECT from a scalar user-defined function.

But the option that many people don’t seem to be aware of, is that you can also use EXEC to call a scalar function.

I remember noticing this in the documentation for the EXEC command some years back. Prior to that, it had never dawned on me that you could use EXEC to call a scalar UDF. It’s also in the oldest documentation that I was able to check, so I’d say it’s worked for a long time.

2026-04-12

The WITH EXECUTE AS clause was a great addition for defining stored procedures and functions, to change the execution context, just for the duration of the stored procedure or function. For example:

CREATE PROC SomeSchema.SomeProc
WITH EXECUTE AS USER = 'Fred'
AS
... 

Mostly I use this with the OWNER option:

CREATE PROC SomeSchema.SomeProc
WITH EXECUTE AS OWNER
AS
... 

It’s also useful during testing, where I can temporarily change my execution context during testing. For example:

EXEC AS USER = 'Fred';

\-- Try some code here while running as Fred

REVERT;

But the option that most people don’t realize is possible, is that you can set the execution context for a single execution like this:

2026-04-10