24May 2021 by Grant Fritchey 2 Comments

Database Fundamentals #30: Create Foreign Keys With T-SQL

Database Fundamentals
You can create foreign keys using TSQL roughly the same way as you created primary keys. You can either use the ALTER TABLE statement to add the foreign key, or, if you already have the parent table created along with it’s primary key, you can use the CREATE TABLE statement to include foreign key constraints. The restrictions for creating foreign keys are still the same when using TSQL. Adding a Foreign Key Using the ALTER TABLE statement is very straight forward as before. This script will create a foreign key relationship between the Personnel.Person table and the Personnel.PersonAddress table: ALTER TABLE Personnel.PersonAddress ADD CONSTRAINT PersonAddress_FK_Person FOREIGN KEY (PersonID) REFERENCES Personnel.Person (PersonID); The ALTER TABLE and ADD CONSTRAINT statements are the same as what you saw before. They respectively refer to…
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10May 2021 by Grant Fritchey No Comments

Query Compile Time

SQL Server, You Can't Do That In Profiler
A question that came up recently was how to track the query compile time. It's actually a pretty interesting question because, there aren't that many ways to tell how long it took to compile the query, and they don't necessarily agree. For most of us, most of the time, compile time for a given query doesn't matter. However, I love telling the story of the query I had on an old system that could run in 90ms, but took 5 minutes to compile. In short, sometimes compile time matters. How To See Query Compile Time If you want to see how long it takes a query to compile, you have, to my knowledge, three options. The first, and possibly easiest, is to look at the plan properties on an execution…
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03May 2021 by Grant Fritchey No Comments

Query Store on Azure SQL Database

SQL Server
Under the covers, Azure SQL Database is just good old fashioned SQL Server and this includes Query Store on Azure. While many things can be different when working with Azure, Query Store just isn't one of them. Let's talk about it a bit. Query Store on Azure Unlike your databases created on a SQL Server instance (big iron, VM, hosted VM, wherever), the databases you create on Azure SQL Database have Query Store enabled by default. Managed Instance and Synapse are different. In their case, they operate the same as an instance of SQL Server, off by default. Further, in the single database of Azure SQL Database, you can't, as in can not, disable Query Store. It's on by default and it's staying that way. This leads to a simple…
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26Apr 2021 by Grant Fritchey 2 Comments

Using Extended Events Live Data With Azure

Azure, SQL Server, You Can't Do That In Profiler
In my last post I showed some shortcomings of Extended Events, however, it is possible to use Live Data with Azure. Let's explore exactly how that works. To get started, you'll need to follow the directions here to get set up with Azure Storage as the output target of your Extended Events session within your Azure SQL Database. There is a little bit of prep work, but it's all laid out in Microsoft's document. I found the Powershell to be a bit sketchy, but it shows you what's needed. The T-SQL just works. Live Data With Azure Once you've created an Extended Events Session that is output to Azure Storage, you've done most of the work. The trick is really simple. Get the Azure Storage account set up with a…
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19Apr 2021 by Grant Fritchey No Comments

Extended Events and Azure SQL Database

SQL Server, You Can't Do That In Profiler
Knowledge of how your system behaves is vital to better control, maintain, and grow the system. While Azure provides all sorts of wonderful assistance within Azure SQL Database, you're still going to need that same knowledge. When it comes to getting detailed information about Azure SQL Database, the tools are a little more limited than with an on-premises instance of SQL Server, or any virtual instance of SQL Server. There are no trace events. To see individual query calls, recompile events, query store behaviors, and so much more, you're going to have to use Extended Events. I'm going to write a series of posts on using Extended Events with Azure SQL Database. Tradition would call for this first post to be an initial how-to. Instead, I want to take a…
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06Apr 2021 by Grant Fritchey 6 Comments

A Year of “Good Morning!”

Professional Development
Just a little over a year ago, I started posting a "Good Morning!" tweet on Twitter every work day. I've kept it up for over a year and I'd like to take a moment to discuss it. Why did I do it? How has it gone? What are the plans for the future? Why "Good Morning!"? I remember deciding to start doing this. We were barely two weeks into the initial lockdown here in Massachusetts. I was in the dumps. Everyone looked to be in the dumps. My very first tweet, not officially part of the timeline, but let's be honest with you all, was a complaint: So glad my son decided to play videos really loud while getting ready for work. I didn't want to sleep at all. GOOD…
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05Apr 2021 by Grant Fritchey 1 Comment

Extended Events: Embrace the XML

SQL Server
While XML is, without a doubt, a giant pain in the bottom, sometimes, the best way to deal with Extended Events is to simply embrace the XML. Now, I know, just last week, I suggested ways to avoid the XML. I will freely admit, that is my default position. If I can avoid the XML, I will certainly do it. However, there are times where just embracing the XML works out nicely. Let's talk about it a little. Copy This Query I have a theory. It goes like this: There has only, ever, been a single XML query written from scratch. All other XML queries are just copied from that one and then edited to do what is necessary OK. Maybe that's not entirely true. In fact, I know it's…
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29Mar 2021 by Grant Fritchey 8 Comments

Extended Events: Avoid the XML

SQL Server, Tools
One story I hear over and over goes like this: I tried setting up Extended Events, but then I saw the output was XML so I stopped. Look, I get it. I don't like XML either. It's a pain to work with. It's actively difficult to write queries against it. If there weren't a ton of ways to avoid the XML, yeah, I would never advocate for Extended Events. However, here we are, I have ten pages of blog posts that at least mention Extended Events. Why? Because I avoid the XML (most of the time). Lots of other people do as well. You can too. Let's see how. Live Data Window I have a video that goes into this in detail right here. But the core concept is simple.…
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22Mar 2021 by Grant Fritchey 9 Comments

Query Store as an Upgrade Tool

SQL Server, Tools
There are a lot of uses for Query Store, but one of the most interesting is as an upgrade tool. We all know that upgrades in SQL Server can be more than a little bit nerve wracking. No matter how much you tested stuff in lower environments, deploying an update to production might result in performance issues as your code hits a regression. This is even more true when upgrading from versions of SQL Server prior to 2014 to anything 2014 and above. That's because of the new cardinality estimation engine introduced in 2014. Most queries won't notice it. Some queries will benefit from the better estimates. A few, problematic, queries will suffer. This is where Query Store can be used as an upgrade tool. The Steps We're going to…
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15Mar 2021 by Grant Fritchey 20 Comments

Apologies

Uncategorized
Hello all! I wanted to apologize to you. I haven't been keeping up with the blog well at all over the last couple of months. I have simply been struggling with motivation. I have enough for my work commitments, but extra-curricular stuff has just been lagging. So, please allow me to say I'm sorry for not getting more sharing out there. Next, I'm making a commitment to you that I will be posting regularly again from this point forward. As a part of that, I'd sure love to hear from you on what kind of content you'd like to see. Do we need more on execution plans, or on SQL Server fundamentals? Would a bunch of stuff on Extended Events or Query Store be more interesting? How much DevOps stuff…
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