When I teach powershell the question I get from DBAs most often is what is an overload. Because when we get into methods you can’t go very long at all without stating that they’re overloaded and most DBAs just don’t live in that world enough to know programming terms like that.

Overloading is when a function, method, or whatever can be called with different sets of parameters. Let’s take a good example of calling the ChangePassword() method under the Logins context. I’m gonna walk you through this step by step because I want to make sure you understand.

Let’s start by opening SSMS and right-clicking on Logins. Then to go Start Powershell.
You’ll be presented with a prompt in the Logins context. Now, if you do a get-member you’ll see a list of properties and methods. We’re concerned with the methods here. As a quick aside, a property is an adjective. It tells you something about the object, while a method is a verb. It’s something you can do to the object. So in our case you can see several properties like SID. SID is a property of a login… it describes something about the login. But the method ChangePassword() is a verb. It’s something we can do to the login. Methods are like functions in SQL more or less. Anyway…

So here’s a query you can type to get down to the info we’re interested in. I’m going to narrow the results down to just the ChangePassword() method we’re interested in so we don’t have to pick through a bunch of results.

dir | gm | ?{$_.name -eq "ChangePassword"} | FL

Here’s a screenshot of the results.

Ok, now we can actually talk about the overloads. Notice that in the Definition column you there are 3 ways to call this method.

1. System.Void ChangePassword(string newPassword)
2. System.Void ChangePassword(string oldPassword, string newPassword)
3. System.Void ChangePassword(string newPassword, bool unlock, bool mustChange)

In the 1st one you can simply pass in the new password.
In the 2nd one you can pass in the old password and the new password.
and in the 3rd one you can pass in the new password along with a bit to unlock the acct and whether they must change it when they login next time.

Each one of these sets of parameter combinations is called an overload. Sometimes you’ll see a method that has no overloads. That means there’s only one way to call it. The Refresh() method is like this. It’s not overloaded because you can only call it one way… with no parameters.

dir | gm | ?{$_.name -eq "Refresh"} | FL

You can see from the output here that there is only one item listed in the Definition column. There’s only one way to call the Refresh() method, and that’s with no parameters. If you try to call it any other way you will get an error.

So a method can either be overloaded or not. And this is how you know how to call any method. You do a get-member on it and look at its definition. You’ve probably noticed by now that the definition also gives you the data types and functions of the parameters it’s expecting. Above for the ChangePassword() method you can see that the newPassword parameter is a string. So you automatically know you’re going to call it like this:
ChangePassword(“MyN3wPassw0rd!!!”)
And you know the 3rd overload takes a string and 2 booleans. So it’ll look like this:
ChangePassword(“MyN3wPassw0rd!!!”, 1, 1)
or like this:
ChangePassword(“MyN3wPassw0rd!!!”, $true, $true)

Ok guys, that’s about it for overloads. I wanted to give a nice thorough explanation for the beginners out there. Sometimes these concepts can be a bit foggy to understand and .Net guys always explaining things with .Net terms doesn’t really help. So I wanted to try to put it in nice plain English.
Let me know if you have any questions.