A Fine Slice Of SQL Server
Tony Wilhelm troubleshoots a nasty problem:
Items that were checked / tried:
- Rebooting server and clients
- Dropping and recreating the SPNs
Oh did I mention that this was SQL Server 2005…
It turns out neither of those was the solution. Click through to learn how to fix the problem.
Comments closedMarco Russo and Alberto Ferrari catalog some errors:
The expression contains columns from multiple tables, but only columns from a single table can be used in a True/False expression that is used as a table filter expression.
This error is seen when the predicate includes column references from more than one table. For example, if we need a measure that returns the sales made to customers living in the same country as the store, we could try to write the following measure:
Read on for several examples and solid guidance on how to resolve these common issues.
Comments closedRandheer Parmar wants row-level security:
Row Level Security is a very key requirement for most database or data lake applications. Most of the databases are having natively build row-level security but Synapse serverless SQL pool doesn’t support this inbuilt functionality. In this article, we will see how to implement it.
Row-level security has always seemed to me to be a great idea but not one I can implement because its performance cost is always too high.
Comments closedRobert Cain continues a series on KQL:
In an earlier post in this series, Fun With KQL – Count, you saw how to use the
countoperator to count the number of rows in a dataset.Then we learned about another operator,
distinct, in the post Fun With KQL – Distinct. This showed how to get a list of distinct values from a table.While we could combine these, it would be logical to have a single command that returns a distinct count in one operation. As you may have guessed by the title of this post, such an operator exists:
dcount.
Read on to see how you can use dcount in queries, including how you can perform speed versus accuracy trade-offs.
Pat Wright asks the community about community:
Listed below is a summary of each person that took part and some of my comments related to the blog post. It was wonderful reading through the blog posts and getting different perspectives from others.
Click through for several posts on the topic.
Comments closedKamil Nowinski goes down a rabbit hole:
This happens on the customer’s Synapse workspace where we have a public network disabled, so only private endpoint and managed VNET are available. Additionally, you probably spotted, that it took over 3 minutes to actually get this message. Hence, as a next step, in order to minimize the potential causes I simplified the query to make sure I have access to the Storage, by listing the files:
Click through for a story of pain, followed by glorious resolution.
Comments closedKevin Wilkie punctuates the statement:
With our last blog post, we started discussing Snowflake and the SELECT statement. Now, if you remember, there is this great thing called a semi-colon.
The main reason you should use the semicolon is to terminate all of your queries. Snowflake does this great thing by default, letting you run one query at a time.
I remember back when Microsoft deprecated T-SQL statements which did not end with semi-colons. It was fun speculating for about 5 minutes regarding the carnage which would happen if they carried out the deprecation notice, not least of which we’d find in Microsoft-developed code.
Comments closedJay Robinson defends the highly defensible:
The point I’m trying to make is that the database code is treated as part of the solution. It is in the repos just like the C# code. It is deployed just like the C# code. I even include unit testing, just like the C# code.
I also keep all T-SQL in the database. There is no T-SQL code inside the C# code. Stored procedures are used for all functionality, even basic CRUD functions. In fact, probably 80–90% of the stored procedures in my systems are essentially CRUD functions. The only operation that doesn’t go through stored procedures is bulk insertion, and I use SqlBulkCopy for that.
Jay makes what I often consider the most important point from the standpoint of developers: that stored procedures act as an interface.
Comments closedBut interestingly enough – we would be getting an added benefit here. Even if there is no SQL injection attack, it’s still possible that such errors would be raised by the application – simply due to bugs.
Furthermore, these errors in the database may be happening without anyone even noticing! How could that be, you ask? Well, it could be due to bad error handling that “swallows” the error entirely, or because the errors are logged but no one is bothering to look at the logs, or maybe because the errors are caught but an undetailed error message is logged/displayed to the user (I can’t even count how many times I encountered “general database error” messages in applications), or because the developers simply decided to mark this as a “known issue” that they didn’t bother to fix and they didn’t think to ask their DBA about it… The reasons are numerous and varying.
Click through for the scripts. I had built something similar about a decade ago, a simple WPF app which watched for errors. I messaged him with something like “You missed a comma in that IN clause” and I saw him pop up from his cubicle and look around, trying to figure out how I could peek over his shoulder and see the query.
1 CommentTomaz Kastrun continues an advent series on Azure ML. Day 4 covers data sources:
Yesterday, we have learned the general outlook of the Studio and in this blog post, we will be focusing primarily on getting data to the workspace and reading data from other data sources.
Day 5 has you provision some compute:
Comments closedWith a basic understanding of data assets, let’s create compute instances. Under “Manage” in the navigation bar, select “Compute” (denoted as 1), select “Compute instances” (d. 2) and click on “+ New”.