Category: Coffee Break (page 1 of 1)

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May 14, 2024 / 0 Comments

Handy Use of a SQL Cursor

Welcome to another coffee break post where I quickly write up something on my mind that can be written and read in less time than a coffee break takes.

Several months ago I ran into a situation where I needed to update the records in one table based on values in a related reference table. To do this update, I was going to need to run an existing stored procedure once for every record in the reference table, which I believe contained information about countries and markets within those countries. The reference table looked something like this:

The stored procedure I needed to run had input parameters for CountryID and MarketID as well as several other things that aren’t important for this post. When I was originally looking at this task I needed to complete, I was not looking forward to running the stored procedure manually dozens of times, one for each combination of Country and Market. But I knew there must be a better way. I’m a programmer, I can find a way to automate this tediousness.

A practical use for a cursor

If you’ve developed SQL code for any length of time, you’ve probably heard an older DBA or database developer tell you to never use cursors! I know that I personally have been reminded of that many times, so I had never even considered using one or tried to use one. But when I was staring down the barrel of updating two values in a procedure execution call, running it, waiting for several minutes for the procedure to complete, then doing it all over again, for dozens of times, I knew I had to give a cursor a try.

I of course had to Google how to write a cursor, since I had never done that before, but was quickly able to write a script I would need. The cursor was created to loop over every record retrieved from the reference table using a query I wrote, and injected each of the CountryID and MarketID values into the input parameters of the stored procedure. This easily automated the tedious manual work that I would have needed to do myself, and it did it in a lot less time since it wasn’t a user having to slowly update each relevant value each time they needed to change.

Summary

Maybe cursors aren’t quite the devil I always believed them to be. I know they can certainly cause performance issues on databases when they’re written into stored procedures and ran regularly, turning what should be set-based work into row-based work, but I have learned that there is at least one fantastic use. And this use will make my life easier going forward any time I need to run one stored procedure a lot of times with different input values.

Sources

Here is the main StackOverflow answer I used to help me write my own query: https://stackoverflow.com/a/2077967. And you can see, the first comment of this answer is literally calling cursors evil, which I find amusing.

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April 16, 2024 / 0 Comments

Two Useful Keyboard Shortcuts for SSMS

Welcome to another coffee break post where I quickly write up something on my mind that can be written and read in less time than a coffee break takes.

This morning I was doing my normal work when I had a realization that I should share something I find super useful and use frequently use in SSMS that a lot of developers seem to not know about. They are small actions but they make your life easier when doing a lot of query editing in SSMS.

How to Minimize the Results Window

I have told many developers about this keyboard shortcut and they all appreciated it. I’m sure most people that frequently work in SSMS would like to be able to minimize and maximize the results window as needed in order to give themselves more screen real estate to work with while coding but still be able to see their query results as needed. But there is no minimize button for the results window of SSMS.

The only way that I know of to minimize and then maximize the results window in SSMS is to do CTRL + R. I use this keyboard shortcut every day at work while writing queries or updating existing queries.

How to Refresh the Intellisense

I have also had to tell many developers about updating the intellisense suggestions of SSMS since it will often trip them up if they don’t know how it works. First, you should understand that the intellisense offered by SSMS is only accurate as of the time you opened your query window or changed the connection for the query window (usually). If you’ve been working in the same query window for a while and have made DDL changes to any tables, functions, stored procedures, etc., intellisense is likely out of date and could tell you that a table or column you’re trying to reference doesn’t exist when you know it does.

If you ever run into this situation where it’s telling you something doesn’t exist but you know it does, use CTRL + SHIFT + R and the intellisense suggestions/corrections will be updated.

Bonus shortcut for Red-Gate SQL Prompt

Similar to the intellisense built in to SSMS, if you are using the SQL Prompt tool from Red-Gate, you can run into the same issue with the tool not recognizing that objects or columns exist when you know that they do. If you run into that issue and would like to update the suggestions list for SQL Prompt, use CTRL + SHIFT + D.

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April 9, 2024 / 0 Comments

How to Set Notepad++ as Your Default Git Editor

Welcome to another coffee break post where I quickly write up something on my mind that can be written and read in less time than a coffee break takes.

When you start working with Git Bash for the first time (or you have your computer completely reimaged and have to reinstall everything again like I did recently), you will likely encounter a command line text editor called Vim to edit your commits or to do any other text editing needed for Git. And if you’re like me, you probably won’t like trying to use a keyboard-only interface for updating your commit messages. If that’s the case, then I have a quick tutorial for how to make Git use a normal text editor to more easily update your commit messages.

What is Vim?

Vim is an open-source text editor that can be used in a GUI interface or a command line interface. My only familiarity with it is with the command line interface, as the default text editor that Git comes installed with. If you don’t update your Git configuration to specify a different text editor, you will see a screen like the following whenever you need to create or update a commit message in a text editor (like when you complete a revert and Git generates a generic commit message for you then gives you the opportunity to update it, or when you want to amend an existing commit). This is what the command line editor version of Vim looks like (at least on my computer).

I personally don’t like this text editor because to use it, you need to know specific keyboard commands to navigate all operations and I don’t want to learn and remember those when I can use a GUI-based text editor instead to make changes more quickly and intuitively.

How to Change Text Editor to Notepad++

The command for changing your default text editor is super simple. I found it from this blog post: How to set Notepad++ as the Git editor instead of Vim.

git config --global core.editor "'C:/Program Files/Notepad++/notepad++.exe' -multiInst -notabbar -nosession -noPlugin"

After you execute that command in Git Bash, you can run this command to test it, which should open up Notepad++ to try to update the last commit you made: git commit --amend.

That blog post then says that you should be able to double-check your Git configuration file to see that the editor has been changed, but my file doesn’t reflect what the other post says despite Notepad++ be opened for commit messages after I ran the change statement. This is what my gitconfig file currently looks like after setting the editor to Notepad++:

So your mileage may vary on that aspect. As long as the change works for me, I’m not too concerned about what the config file looks like.

How to Revert Text Editor to Vim

If you ever want to change back to the default text editor, you can run the following command to switch back to Vim, and once again confirm it worked using the git commit --amend statement: 

git config --global core.editor "vim"

Conclusion

Changing your default text editor for Git Bash is extremely simple as long as you know where the exe file of your preferred editor is stored on your computer. It’s also simple to change back to the default Vim editor in the future if you want or need to.

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March 26, 2024 / 1 Comment

Updatable Views

Welcome to a coffee break post where I quickly write up something on my mind that can be written and read in less time than a coffee break takes.

Recently, while exploring possible options for converting our existing ETLs to working with Postgres, I found myself asking the question “can you update a table using a view that has been created on that table?” and the answer is Yes for both Postgres and SQL Server, which I learned after doing some research.

In Postgres, there is a concept of an updatable view, which is essentially a very simple view, that usually doesn’t include a join to a second (or third or more) table. There are other qualifications for what makes a view updatable, but it is generally the fact that the query creating the view is very simple. If a view meets these criteria, you can in fact update the base table using a query to the view.

For example, if you have a table called employee, then you create a view on top of that table which selects most but not all the columns from the base table, with the view being called v_employee, you can then run this query and it will update the data in employee.

UPDATE v_employee
SET full_name = 'George Smith'
WHERE emp_id = 15;

This concept is intriguing to me, and could also be really useful in updating our ETLs more quickly after we convert to Postgres, so I thought I would share this fun little fact with everyone.

Sources

Picture of a keyboard with large yellow X button
Photo by Sam Pak on Unsplash
February 27, 2024 / 0 Comments

Why CFTs Take so Long to Delete

Welcome to another coffee break post where I quickly write up something on my mind that can be written and read in less time than a coffee break takes.

Background

Recently, I went through an AWS workshop for Lake Formation, a data lake management tool in AWS, and that workshop had me create many different Cloud Formation Templates (CFTs) to spin up services to use in the workshop. After I finished that, I then had to go through my development AWS account for work and clean up everything that had been created so we stopped paying for these services I no longer needed.

While attempting to delete the many CFTs I had used, I saw one that was seemingly stuck in the DELETE_IN_PROGRESS state for almost 20 minutes. I did not realize it would take so long to delete one CFT and was getting worried that it was actually stuck. So I started searching online to see if this has happened to others as well.

Why does the delete take so long?

I found this Reddit post of someone reporting the same thing, and it linked to a very informative answer to a similar question on Stack Overflow. I would recommend you go and read that detailed answer there for the best understanding of why CFTs sometimes take forever to delete.

The simple answer is that is just how it is. My CFT in question had set up a lot of Virtual Private Clouds (VPCs), Elastic Compute Cloud (EC2) instances, Elastic Network Interfaces (ENIs) as well as other resources, and some of those items simply take awhile to delete.

Even though I can’t speed up the deletion process for these big CFTs, at least now I know that in the future, should I need to delete any other large CFTs from my AWS account, I can expect it might take longer than I would anticipate to complete.

January 18, 2024 / 0 Comments

More Postgres vs. SQL Server

Welcome to a coffee break post where I quickly write up something on my mind that can be written and read in less time than a coffee break takes.

As I’m getting further into my PostgreSQL adoption project at work, I am continuing to learn about so many more small differences between Postgres and SQL Server that I never would have expected. None of the differences I’ve found so far are profound, but they will pose challenges for all the developers we have (including myself) that have only worked with SQL Server.

Postgres does not have default constraints

That’s right, there is no way to make a default constraint on a Postgres table, instead you make a default value, which cannot have a name assigned to it. In SQL Server, you can define a default constraint in essentially the same way as you would define a unique or key constraint and you can give that constraint a name. In Postgres, you simply specify that a column has a default value when adding that column to a table. In theory (I haven’t tested it yet), the generation of default values works exactly the same between the two engines, one just isn’t saved as it’s own script or file with a name.

The index differences are amazing (and confusing)

I’m not going to lie, the prospect of figuring out when to use what kind of index with Postgres is daunting to me. Deciding which type of index to use with SQL Server is very straightforward, since you only need to know if you already have a primary key/clustered index on the table already and then go from there. You pretty much only have clustered or non-clustered indexes in SQL Server. But Postgres has a handful of different possible options and you need to better know how the data will be queried in order to pick the best one. The default/usual best option seems to be a B-Tree index, which is comforting and familiar, but one day I know I’ll likely have to figure out the other options as well.

The default length of object names is really short

Of these three new items I learned recently, I think this one is going to be the most annoying. The name length for objects in Postgres is surprisingly low, only 31 characters. The max length for objects in SQL Server is much longer. I’m mostly concerned that we’re going to need to figure out how to rename many long object names as we migrate off SQL Server, and that could be tedious. But we’ll see how that goes. I read somewhere in my research that you may be able to change this default length, so that will need to be something else for me to research.

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