functions/Remove-DbaDbMasterKey.ps1

function Remove-DbaDbMasterKey {
    <#
    .SYNOPSIS
        Deletes specified database master key
 
    .DESCRIPTION
        Deletes specified database master key
 
    .PARAMETER SqlInstance
        The target SQL Server instance or instances.
 
    .PARAMETER SqlCredential
        Login to the target instance using alternative credentials. Accepts PowerShell credentials (Get-Credential).
 
        Windows Authentication, SQL Server Authentication, Active Directory - Password, and Active Directory - Integrated are all supported.
 
        For MFA support, please use Connect-DbaInstance.
 
    .PARAMETER Database
        The database where the master key will be removed.
 
    .PARAMETER ExcludeDatabase
        List of databases to exclude from clearing all master keys
 
    .PARAMETER All
        Purge the master keys from all databases on an instance
 
    .PARAMETER InputObject
        Enables pipeline input from Get-DbaDatabase
 
    .PARAMETER EnableException
        By default, when something goes wrong we try to catch it, interpret it and give you a friendly warning message.
        This avoids overwhelming you with "sea of red" exceptions, but is inconvenient because it basically disables advanced scripting.
        Using this switch turns this "nice by default" feature off and enables you to catch exceptions with your own try/catch.
 
    .PARAMETER WhatIf
        Shows what would happen if the command were to run. No actions are actually performed.
 
    .PARAMETER Confirm
        Prompts you for confirmation before executing any changing operations within the command.
 
    .NOTES
        Tags: Certificate, Masterkey
        Author: Chrissy LeMaire (@cl), netnerds.net
        Website: https://dbatools.io
        Copyright: (c) 2018 by dbatools, licensed under MIT
        License: MIT https://opensource.org/licenses/MIT
 
    .LINK
        https://dbatools.io/Remove-DbaMasterKey
 
    .EXAMPLE
        PS C:\> Remove-DbaDbMasterKey -SqlInstance sql2017, sql2016 -Database pubs
 
        The master key in the pubs database on sql2017 and sql2016 will be removed if it exists.
 
    .EXAMPLE
        PS C:\> Remove-DbaDbMasterKey -SqlInstance sql2017 -Database db1 -Confirm:$false
 
        Suppresses all prompts to remove the master key in the 'db1' database and drops the key.
 
    .EXAMPLE
        PS C:\> Get-DbaDbMasterKey -SqlInstance sql2017 -Database db1 | Remove-DbaDbMasterKey -Confirm:$false
 
        Suppresses all prompts to remove the master key in the 'db1' database and drops the key.
 
    #>

    [CmdletBinding(DefaultParameterSetName = "Default", SupportsShouldProcess, ConfirmImpact = "High")]
    param (
        [DbaInstanceParameter[]]$SqlInstance,
        [System.Management.Automation.PSCredential]$SqlCredential,
        [string[]]$Database,
        [string[]]$ExcludeDatabase,
        [switch]$All,
        [parameter(ValueFromPipeline)]
        [Microsoft.SqlServer.Management.Smo.MasterKey[]]$InputObject,
        [switch]$EnableException
    )

    process {
        if ($SqlInstance) {
            if (-not $Database -and -not $ExcludeDatabase -and -not $All) {
                Stop-Function -Message "You must specify Database, ExcludeDatabase or All when using SqlInstance"
                return
            }
            # all does not need to be addressed in the code because it gets all the dbs if $databases is empty
            $databases = Get-DbaDatabase -SqlInstance $SqlInstance -SqlCredential $SqlCredential -Database $Database -ExcludeDatabase $ExcludeDatabase
            if ($databases) {
                foreach ($key in $databases.MasterKey) {
                    $InputObject += $key
                }
            }
        }

        foreach ($masterkey in $InputObject) {
            $server = $masterkey.Parent.Parent
            $db = $masterkey.Parent
            if ($Pscmdlet.ShouldProcess($server.Name, "Removing master key on $($db.Name)")) {
                # avoid enumeration issues
                try {
                    $masterkey.Parent.Query("DROP MASTER KEY")
                    [pscustomobject]@{
                        ComputerName = $server.ComputerName
                        InstanceName = $server.ServiceName
                        SqlInstance  = $server.DomainInstanceName
                        Database     = $db.Name
                        Status       = "Master key removed"
                    }
                } catch {
                    Stop-Function -Message "Failure" -ErrorRecord $_ -Continue
                }
            }
        }
    }
}