{"id":6631,"date":"2015-04-16T00:01:00","date_gmt":"2015-04-16T00:01:00","guid":{"rendered":"https:\/\/blogs.technet.microsoft.com\/heyscriptingguy\/2015\/04\/16\/look-at-schema-of-wmi-class-with-powershell\/"},"modified":"2019-02-18T10:29:52","modified_gmt":"2019-02-18T17:29:52","slug":"look-at-schema-of-wmi-class-with-powershell","status":"publish","type":"post","link":"https:\/\/devblogs.microsoft.com\/scripting\/look-at-schema-of-wmi-class-with-powershell\/","title":{"rendered":"Look at Schema of WMI Class with PowerShell"},"content":{"rendered":"

Summary<\/b>: Microsoft Scripting Guy, Ed Wilson, talks about using Windows PowerShell to look at the schema of a WMI class.<\/span>\nMicrosoft Scripting Guy, Ed Wilson, is here. One of the cool things about WMI is that it is largely self-describing. This means that I can use WMI and look at WMI. With the CIM cmdlets, this goes even a step further. For example, if I want to look at the Win32_Desktop<\/b> WMI class, I can use the Get-CimClass<\/b> cmdlet, and examine it:<\/p>\n

PS C:> Get-CimClass win32_desktop<\/p>\n

   NameSpace: ROOT\/cimv2<\/p>\n

CimClassName         CimClassMethods      CimClassProperties      <\/p>\n

————                        —————          ——————      <\/p>\n

Win32_Desktop                       {}                   {Caption, Description,…\nFrom this output, I can see that the class appears in the Root\/cimv2 WMI namespace. Not really a surprise because that is the default namespace. I can also see that there are no methods. This means that I will not be able to do much more than view information. I can drill down further to see the properties. To do this, I select and expand the cimClassProperties<\/b> property. This is shown here:<\/p>\n

Get-CimClass win32_desktop | select -ExpandProperty cimclassproperties\nThe output, however, scrolls and scrolls because each property is more than a simple name. It contains qualifiers, flags, and more. Here is the output for the first couple of properties:<\/p>\n

PS C:> Get-CimClass win32_desktop | select -ExpandProperty cimclassproperties<\/p>\n

Name               : Caption<\/p>\n

Value              :<\/p>\n

CimType            : String<\/p>\n

Flags              : Property, ReadOnly, NullValue<\/p>\n

Qualifiers         : {MaxLen, read}<\/p>\n

ReferenceClassName :<\/p>\n

Name               : Description<\/p>\n

Value              :<\/p>\n

CimType            : String<\/p>\n

Flags              : Property, ReadOnly, NullValue<\/p>\n

Qualifiers         : {read}<\/p>\n

ReferenceClassName :\nOne of the things that is interesting is that the qualifiers are Read Only. Some properties are actually Read\/Write; therefore, the class may not expose a method, but it still has updatable properties. I first look for all Read<\/b> <\/i>properties. This command and partial output are shown here:<\/p>\n

PS C:> (Get-CimClass win32_desktop | select -ExpandProperty cimclassproperties).where({$psitem.qualifiers -match ‘read’})<\/p>\n

Name               : Caption<\/p>\n

Value              :<\/p>\n

CimType            : String<\/p>\n

Flags              : Property, ReadOnly, NullValue<\/p>\n

Qualifiers         : {MaxLen, read}<\/p>\n

ReferenceClassName :<\/p>\n

Name               : Description<\/p>\n

Value              :<\/p>\n

CimType            : String<\/p>\n

Flags              : Property, ReadOnly, NullValue<\/p>\n

Qualifiers         : {read}<\/p>\n

ReferenceClassName : \nNow, I want to see if there are any writable properties exposed via this class. Here is the command I use:<\/p>\n

PS C:> (Get-CimClass win32_desktop | select -ExpandProperty cimclassproperties).where({$psitem.qualifiers -match ‘write’})<\/p>\n

PS C:> \nHmm…nothing comes back.\nWell, that was to be expected. I happen to know of a WMI class, Win32_ComputerSystem<\/b>, that contains a few writable properties. So I test my command on that class. Here is the command and the results:<\/p>\n

PS C:> (Get-CimClass win32_computersystem | select -ExpandProperty cimclassproperties).where({$psitem.qualifiers -match ‘write’})<\/p>\n

Name               : Roles<\/p>\n

Value              :<\/p>\n

CimType            : StringArray<\/p>\n

Flags              : Property, NullValue<\/p>\n

Qualifiers         : {read, write}<\/p>\n

ReferenceClassName :<\/p>\n

Name               : AutomaticManagedPagefile<\/p>\n

Value              :<\/p>\n

CimType            : Boolean<\/p>\n

Flags              : Property, NullValue<\/p>\n

Qualifiers         : {MappingStrings, read, write}<\/p>\n

ReferenceClassName :<\/p>\n

Name               : AutomaticResetBootOption<\/p>\n

Value              :<\/p>\n

CimType            : Boolean<\/p>\n

Flags              : Property, NullValue<\/p>\n

Qualifiers         : {MappingStrings, read, write}<\/p>\n

ReferenceClassName :<\/p>\n

Name               : CurrentTimeZone<\/p>\n

Value              :<\/p>\n

CimType            : SInt16<\/p>\n

Flags              : Property, NullValue<\/p>\n

Qualifiers         : {MappingStrings, read, write}<\/p>\n

ReferenceClassName :<\/p>\n

Name               : EnableDaylightSavingsTime<\/p>\n

Value              :<\/p>\n

CimType            : Boolean<\/p>\n

Flags              : Property, NullValue<\/p>\n

Qualifiers         : {write}<\/p>\n

ReferenceClassName :<\/p>\n

Name               : SystemStartupDelay<\/p>\n

Value              :<\/p>\n

CimType            : UInt16<\/p>\n

Flags              : Property, NullValue<\/p>\n

Qualifiers         : {DEPRECATED, MappingStrings, Privileges, read…}<\/p>\n

ReferenceClassName :<\/p>\n

Name               : SystemStartupOptions<\/p>\n

Value              :<\/p>\n

CimType            : StringArray<\/p>\n

Flags              : Property, NullValue<\/p>\n

Qualifiers         : {DEPRECATED, MappingStrings, Privileges, read…}<\/p>\n

ReferenceClassName :<\/p>\n

Name               : SystemStartupSetting<\/p>\n

Value              :<\/p>\n

CimType            : UInt8<\/p>\n

Flags              : Property, NullValue<\/p>\n

Qualifiers         : {DEPRECATED, MappingStrings, Privileges, read…}<\/p>\n

ReferenceClassName :<\/p>\n

Name               : Workgroup<\/p>\n

Value              :<\/p>\n

CimType            : String<\/p>\n

Flags              : Property, NullValue<\/p>\n

Qualifiers         : {MappingStrings, read, write}<\/p>\n

ReferenceClassName :\nIt seems that some of the properties are deprecated. This means that I am not supposed to use them. I wonder if I can find an easier way to see this information. I modify my command. This command is pretty long, and it is a single-line command that wrapped on the blog:<\/p>\n

PS C:> (Get-CimClass win32_computersystem | select -ExpandProperty cimclassproperties).where({$psitem.qualifiers -match ‘write’ -and $psitem.qualifiers -match ‘deprecated’})<\/p>\n

Name               : SystemStartupDelay<\/p>\n

Value              :<\/p>\n

CimType            : UInt16<\/p>\n

Flags              : Property, NullValue<\/p>\n

Qualifiers         : {DEPRECATED, MappingStrings, Privileges, read…}<\/p>\n

ReferenceClassName :<\/p>\n

Name               : SystemStartupOptions<\/p>\n

Value              :<\/p>\n

CimType            : StringArray<\/p>\n

Flags              : Property, NullValue<\/p>\n

Qualifiers         : {DEPRECATED, MappingStrings, Privileges, read…}<\/p>\n

ReferenceClassName :<\/p>\n

Name               : SystemStartupSetting<\/p>\n

Value              :<\/p>\n

CimType            : UInt8<\/p>\n

Flags              : Property, NullValue<\/p>\n

Qualifiers         : {DEPRECATED, MappingStrings, Privileges, read…}<\/p>\n

ReferenceClassName :\nIt looks like the startup stuff is all deprecated.\nIf I only want to look at the property names, I can choose it directly from my query. This is shown here:<\/p>\n

PS C:> (Get-CimClass win32_desktop | select -ExpandProperty cimclassproperties).name<\/p>\n

Caption<\/p>\n

Description<\/p>\n

SettingID<\/p>\n

BorderWidth<\/p>\n

CoolSwitch<\/p>\n

CursorBlinkRate<\/p>\n

DragFullWindows<\/p>\n

GridGranularity<\/p>\n

IconSpacing<\/p>\n

IconTitleFaceName<\/p>\n

IconTitleSize<\/p>\n

IconTitleWrap<\/p>\n

Name<\/p>\n

Pattern<\/p>\n

ScreenSaverActive<\/p>\n

ScreenSaverExecutable<\/p>\n

ScreenSaverSecure<\/p>\n

ScreenSaverTimeout<\/p>\n

Wallpaper<\/p>\n

WallpaperStretched<\/p>\n

WallpaperTiled\nBecause I may not know what qualifiers a WMI class supports, I can easily use the Get-CimClass<\/b> cmdlet to return those qualifiers:<\/p>\n

PS C:> (Get-CimClass win32_process).CimClassQualifiers.name<\/p>\n

Locale<\/p>\n

UUID<\/p>\n

CreateBy<\/p>\n

DeleteBy<\/p>\n

dynamic<\/p>\n

provider<\/p>\n

SupportsCreate<\/p>\n

SupportsDelete<\/p>\n

PS C:> (Get-CimClass win32_desktop).CimClassQualifiers.name<\/p>\n

Locale<\/p>\n

UUID<\/p>\n

dynamic<\/p>\n

Privileges<\/p>\n

provider<\/p>\n

PS C:> (Get-CimClass win32_Computersystem).CimClassQualifiers.name<\/p>\n

Locale<\/p>\n

UUID<\/p>\n

dynamic<\/p>\n

provider<\/p>\n

SupportsUpdate\nKeep in mind that these are qualifiers on the WMI class itself, not qualifiers on the properties. I can obtain a list of all the qualifiers on all of the properties, sort them, and then get the unique qualifier names. This is shown here:<\/p>\n

PS C:> (Get-CimClass win32_process | select -ExpandProperty cimclassproperties).qualifiers.name | sort | get-unique<\/p>\n

CIM_Key<\/p>\n

Fixed<\/p>\n

key<\/p>\n

MappingStrings<\/p>\n

MaxLen<\/p>\n

Override<\/p>\n

Privileges<\/p>\n

Propagated<\/p>\n

read<\/p>\n

ValueMap\nThat is all there is to using Windows PowerShell to look at a WMI class schema. CIM Week will continue tomorrow when I will talk about more cool stuff.<\/span>\nI invite you to follow me on Twitter<\/a> and Facebook<\/a>. If you have any questions, send email to me at scripter@microsoft.com<\/a>, or post your questions on the Official Scripting Guys Forum<\/a>. See you tomorrow. Until then, peace.\nEd Wilson, Microsoft Scripting Guy<\/b> <\/span><\/p>\n","protected":false},"excerpt":{"rendered":"

Summary: Microsoft Scripting Guy, Ed Wilson, talks about using Windows PowerShell to look at the schema of a WMI class. Microsoft Scripting Guy, Ed Wilson, is here. One of the cool things about WMI is that it is largely self-describing. This means that I can use WMI and look at WMI. With the CIM cmdlets, […]<\/p>\n","protected":false},"author":596,"featured_media":87096,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[1],"tags":[385,3,4,45,6],"class_list":["post-6631","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-scripting","tag-cim","tag-scripting-guy","tag-scripting-techniques","tag-windows-powershell","tag-wmi"],"acf":[],"blog_post_summary":"

Summary: Microsoft Scripting Guy, Ed Wilson, talks about using Windows PowerShell to look at the schema of a WMI class. Microsoft Scripting Guy, Ed Wilson, is here. One of the cool things about WMI is that it is largely self-describing. This means that I can use WMI and look at WMI. With the CIM cmdlets, […]<\/p>\n","_links":{"self":[{"href":"https:\/\/devblogs.microsoft.com\/scripting\/wp-json\/wp\/v2\/posts\/6631","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/devblogs.microsoft.com\/scripting\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/devblogs.microsoft.com\/scripting\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/devblogs.microsoft.com\/scripting\/wp-json\/wp\/v2\/users\/596"}],"replies":[{"embeddable":true,"href":"https:\/\/devblogs.microsoft.com\/scripting\/wp-json\/wp\/v2\/comments?post=6631"}],"version-history":[{"count":0,"href":"https:\/\/devblogs.microsoft.com\/scripting\/wp-json\/wp\/v2\/posts\/6631\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/devblogs.microsoft.com\/scripting\/wp-json\/wp\/v2\/media\/87096"}],"wp:attachment":[{"href":"https:\/\/devblogs.microsoft.com\/scripting\/wp-json\/wp\/v2\/media?parent=6631"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/devblogs.microsoft.com\/scripting\/wp-json\/wp\/v2\/categories?post=6631"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/devblogs.microsoft.com\/scripting\/wp-json\/wp\/v2\/tags?post=6631"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}