Category: Powershell

Thomas Rayner points out a cool addition to parameter validation as of Powershell 6:

If you’ve written at least a couple of advanced PowerShell functions, you’re probably no stranger to parameter validation. These are the attributes you attach to parameters to make sure that they match a certain regular expression using [ValidatePattern()], or that when they are plugged into a certain script, that it evaluates to true using [ValidateScript({})]. You’ve probably also used [ValidateRange()] to make sure a number falls between a min and a max value that you specified.

In PowerShell 6, though, there’s something new and cool you can do with ValidateRange. You can specify in a convenient new syntax that the value must be positive or negative.

Read on to see a few examples.

Shane O’Neill looks at variable scope within script blocks in Powershell:

Now what happens if we don’t want to use switch? What happens if we tried to do this with script blocks instead?

I’ve created 3 different script blocks here just for ease of use. If you want to create a single script block to do this then I encourage it! Let me know how you get on.

We’re also passing in the parameter into the script block by passing it in the brackets of the .InvokeReturnAsIs() method.

Read on and learn along with Shane.

Steve Stedman has a quick Powershell one-liner to concatenate multiple files:

I come across the need occasionally to deploy a set of sql files that are all checked into source control in different files with a file hierarchy like this:

• Database Name
  • Type of object (proc, table, view, etc)
    • Name of object

When I go to deploy the scripts I need to manually combine all the SQL files into one to move to production, qa or test for deployment. After getting annoyed at lots of copy and paste I finally discovered an easy powershell script to combine all the files into one.

Steve points out at the end that if the file does not end with “GO” then combining multiple things, like stored procedures, together might result in unexpected behavior.  I’ve done something similar to Steve’s script, except as you stream the content, append a newline, “GO,” and another newline.

Andy Levy helps an end user understand a database schema:

This week I had a user come to me asking about how fields were defined on a few tables he was using in writing some reports. Long story short, he’s been tasked with writing some new reports and updating existing ones, but he doesn’t have visibility to the database itself so he’s left with the “ok, let’s try this” approach and then reading error messages to debug when things go sideways. Very tedious.

I asked him for a list of the tables he was most interested in, and while he worked on that I set to work on (of course) a quick & dirty PowerShell script to collect the data he needed – field names, types, and whether they’re nullable.

Ideally these analysts would have data model documentation, but it’s not an ideal world.