1. PowerShell Best Practices for SQL DBA’s
Ed Wilson, MCDBA
Microsoft Scripting Guy
1/10/2019

2. Ed Wilson Microsoft Scripting Guy
“Windows PowerShell 2.0 Best Practices”
@ScriptingGuys
Mr.Ed.Wilson on Facebook
Ed Wilson on Linked In

3. Objectives and Take-Aways
!($local:BestPractice -eq $global:BestPractice)
Script Progression
TechNet Script Center
FaceBook – Friend Me Mr.Ed.Wilson

4. What is Windows PowerShell?
Console
Interactive commands
Query and configure
Run jobs
Scripting language
Automate everything
Sharable and reusable
Windows PowerShell 2.0 comes in two flavors: the command line version, and the script version. You can think of combining the DOS prompt with VBScript. This is something that is foreign to Windows people, but has been around in other computing environments for a long time.
The console gives you the ability to quickly run cmdlets, external executables, and even code in an interactive fashion. In Windows PowerShell 2.0 you can work on the local host, or run commands against remote computers.
Windows PowerShell scripts can use the same cmdlets that are used in the PowerShell console, but can also use COM objects, .NET Framework classes, ADSI, ADO, WMI, and even WIN32 API’s.
In the Windows PowerShell console, there is a Start-Transcript cmdlet that records your commands and associated output. I have written a Start-Transcript function for the Windows PowerShell ISE.

5. Progression Modules Advanced Functions Functions Quick Script Console
Complexity and Development Time
Console

6. Using Console Aliases Positional Arguments
Partial parameter completion
Variables
Profile functions and aliases
Include files (dot sourcing)
Import-history

7. Using Windows PowerShell Console
Demo
Using Windows PowerShell Console

8. Quick Script Basically collection of Windows PowerShell commands
Add variables
Error handling
Comments
Straight line execution of script
If use parameters, add some kind of help
#Requires –Version 2.0
Quick scripts range in usefullness and complexity from a collection of commands – and therefore help you to remember that cool sequence you were not sure would work – but did, to scripts that use variables, error handling, and comments. If the script accepts arguments, or parameters, make sure you add some kind of help with an example syntax.

9. Demo
DemoScriptCommands.ps1

10. Functions Use Verb-Noun Include closing #end function
Use Param, not ($myparameter)
Use type constraint on parameters
Supply default values for params
Consider partial param completion in names
Choose names that do not conflict
Create unique alias for function
Use Test-Path to check resource
Use Join-Path when building path to resource
Often that quick script you dashed off, proved to be rather useful. The next stage in the evolution is to migrate the code and put it into a function. This facilitates re-use – either by copy / paste method, or by dot sourcing the function.

11. Demo Function
DemoScriptFunction.ps1

12. Advanced Function Help tags Avoid Throw unless actually causes error
.Synopsis
.Example
Avoid Throw unless actually causes error
Parameter Validation attributes
Avoid Out-Host, Out-Default
Return Objects
Do not make permanent modifications Env
Advanced functions in the Windows PowerShell 2.0 beta were called script cmdlets – a name I still like. Because advanced functions can be used to act like cmdlets: integrate with Get-Help, accept pipeline input, implement parameter validation and do some really sophisticated stuff. You can do all this, and leave the function in a script if you wish, or you may want to migrate it to a separate file to facilitate importing (dot sourcing) or begin thinking about creating a module.

13. Practical Example
Evolution of a function … the conversion module demo 
First 6 installments of Weekend Scripter on Hey Scripting Guy blog.

14. TechNet Script Center
Hey Scripting Guy Blog – 99% PowerShell for last 24 months
Hey Scripting Guy is 7 days a week!
Script Repository – Over 5,000 scripts –some cool, others rather rudimentary.
Official Scripting Guys Forum – sweet!
TechNet Library content – good stuff
Downloads page = nice
Coming = more videos, etc.

15. Social media www.ScriptingGuys.Com http://bit.ly/hsgblog
Scripting Guys group on Facebook
Scripting Guys fan page on Facebook
Mr.Ed.Wilson on Facebook
Ed Wilson on Linked In