functions/Repair-DbaOrphanUser.ps1

#ValidationTags#Messaging,FlowControl,Pipeline,CodeStyle#
function Repair-DbaOrphanUser {
    <#
    .SYNOPSIS
        Finds orphan users with existing login and remaps them.
 
    .DESCRIPTION
        An orphan user is defined by a user that does not have a matching login (Login property = "").
 
        If the matching login exists it must be:
        Enabled
        Not a system object
        Not locked
        Have the same name that user
 
        You can drop users that does not have their matching login by specifying the parameter -RemoveNotExisting.
 
    .PARAMETER SqlInstance
        The target SQL Server instance or instances.
 
    .PARAMETER SqlCredential
        Login to the target instance using alternative credentials. Windows and SQL Authentication supported. Accepts credential objects (Get-Credential)
 
    .PARAMETER Database
        Specifies the database(s) to process. Options for this list are auto-populated from the server. If unspecified, all databases will be processed.
 
    .PARAMETER ExcludeDatabase
        Specifies the database(s) to exclude from processing. Options for this list are auto-populated from the server
 
    .PARAMETER Users
        Specifies the list of usernames to repair.
 
    .PARAMETER Force
        Forces alter schema to dbo owner so users can be dropped.
 
    .PARAMETER RemoveNotExisting
        If this switch is enabled, all users that do not have a matching login will be dropped from the database.
 
    .PARAMETER WhatIf
        If this switch is enabled, no actions are performed but informational messages will be displayed that explain what would happen if the command were to run.
 
    .PARAMETER Confirm
        If this switch is enabled, you will be prompted for confirmation before executing any operations that change state.
 
    .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.
 
    .NOTES
        Tags: Orphan
        Author: Claudio Silva (@ClaudioESSilva) | Simone Bizzotto (@niphlod)
 
        Website: https://dbatools.io
        Copyright: (c) 2018 by dbatools, licensed under MIT
        License: MIT https://opensource.org/licenses/MIT
 
    .LINK
        https://dbatools.io/Repair-DbaOrphanUser
 
    .EXAMPLE
        PS C:\> Repair-DbaOrphanUser -SqlInstance sql2005
 
        Finds and repairs all orphan users of all databases present on server 'sql2005'
 
    .EXAMPLE
        PS C:\> Repair-DbaOrphanUser -SqlInstance sqlserver2014a -SqlCredential $cred
 
        Finds and repair all orphan users in all databases present on server 'sqlserver2014a'. SQL credentials are used to authenticate to the server.
 
    .EXAMPLE
        PS C:\> Repair-DbaOrphanUser -SqlInstance sqlserver2014a -Database db1, db2
 
        Finds and repairs all orphan users in both db1 and db2 databases.
 
    .EXAMPLE
        PS C:\> Repair-DbaOrphanUser -SqlInstance sqlserver2014a -Database db1 -Users OrphanUser
 
        Finds and repairs user 'OrphanUser' in 'db1' database.
 
    .EXAMPLE
        PS C:\> Repair-DbaOrphanUser -SqlInstance sqlserver2014a -Users OrphanUser
 
        Finds and repairs user 'OrphanUser' on all databases
 
    .EXAMPLE
        PS C:\> Repair-DbaOrphanUser -SqlInstance sqlserver2014a -RemoveNotExisting
 
        Finds all orphan users of all databases present on server 'sqlserver2014a'. Removes all users that do not have matching Logins.
 
    #>

    [CmdletBinding(SupportsShouldProcess = $true)]
    param (
        [parameter(Mandatory, ValueFromPipeline)]
        [Alias("ServerInstance", "SqlServer")]
        [DbaInstanceParameter[]]$SqlInstance,
        [PSCredential]$SqlCredential,
        [Alias("Databases")]
        [object[]]$Database,
        [object[]]$ExcludeDatabase,
        [parameter(Mandatory = $false, ValueFromPipeline)]
        [object[]]$Users,
        [switch]$RemoveNotExisting,
        [switch]$Force,
        [Alias('Silent')]
        [switch]$EnableException
    )

    process {

        foreach ($instance in $SqlInstance) {

            try {
                $server = Connect-SqlInstance -SqlInstance $instance -SqlCredential $SqlCredential
            } catch {
                Write-Message -Level Warning -Message "Failed to connect to: $SqlInstance."
                continue
            }

            $DatabaseCollection = $server.Databases | Where-Object IsAccessible

            if ($Database) {
                $DatabaseCollection = $DatabaseCollection | Where-Object Name -In $Database
            }
            if ($ExcludeDatabase) {
                $DatabaseCollection = $DatabaseCollection | Where-Object Name -NotIn $ExcludeDatabase
            }

            if ($DatabaseCollection.Count -gt 0) {
                foreach ($db in $DatabaseCollection) {
                    try {
                        #if SQL 2012 or higher only validate databases with ContainmentType = NONE
                        if ($server.versionMajor -gt 10) {
                            if ($db.ContainmentType -ne [Microsoft.SqlServer.Management.Smo.ContainmentType]::None) {
                                Write-Message -Level Warning -Message "Database '$db' is a contained database. Contained databases can't have orphaned users. Skipping validation."
                                Continue
                            }
                        }

                        Write-Message -Level Verbose -Message "Validating users on database '$db'."

                        if ($Users.Count -eq 0) {
                            #the third validation will remove from list sql users without login. The rule here is Sid with length higher than 16
                            $UsersToWork = $db.Users | Where-Object { $_.Login -eq "" -and ($_.ID -gt 4) -and (($_.Sid.Length -gt 16 -and $_.LoginType -in @([Microsoft.SqlServer.Management.Smo.LoginType]::SqlLogin, [Microsoft.SqlServer.Management.Smo.LoginType]::Certificate)) -eq $false) }
                        } else {
                            #the fourth validation will remove from list sql users without login. The rule here is Sid with length higher than 16
                            $UsersToWork = $db.Users | Where-Object { $_.Login -eq "" -and ($_.ID -gt 4) -and ($Users -contains $_.Name) -and (($_.Sid.Length -gt 16 -and $_.LoginType -in @([Microsoft.SqlServer.Management.Smo.LoginType]::SqlLogin, [Microsoft.SqlServer.Management.Smo.LoginType]::Certificate)) -eq $false) }
                        }

                        if ($UsersToWork.Count -gt 0) {
                            Write-Message -Level Verbose -Message "Orphan users found"
                            $UsersToRemove = @()
                            foreach ($User in $UsersToWork) {
                                $ExistLogin = $server.logins | Where-Object {
                                    $_.Isdisabled -eq $False -and
                                    $_.IsSystemObject -eq $False -and
                                    $_.IsLocked -eq $False -and
                                    $_.Name -eq $User.Name
                                }

                                if ($ExistLogin) {
                                    if ($server.versionMajor -gt 8) {
                                        $query = "ALTER USER " + $User + " WITH LOGIN = " + $User
                                    } else {
                                        $query = "exec sp_change_users_login 'update_one', '$User'"
                                    }

                                    if ($Pscmdlet.ShouldProcess($db.Name, "Mapping user '$($User.Name)'")) {
                                        $server.Databases[$db.Name].ExecuteNonQuery($query) | Out-Null
                                        Write-Message -Level Verbose -Message "User '$($User.Name)' mapped with their login."

                                        [PSCustomObject]@{
                                            ComputerName = $server.ComputerName
                                            InstanceName = $server.ServiceName
                                            SqlInstance  = $server.DomainInstanceName
                                            DatabaseName = $db.Name
                                            User         = $User.Name
                                            Status       = "Success"
                                        }
                                    }
                                } else {
                                    if ($RemoveNotExisting) {
                                        #add user to collection
                                        $UsersToRemove += $User
                                    } else {
                                        Write-Message -Level Verbose -Message "Orphan user $($User.Name) does not have matching login."
                                        [PSCustomObject]@{
                                            ComputerName = $server.ComputerName
                                            InstanceName = $server.ServiceName
                                            SqlInstance  = $server.DomainInstanceName
                                            DatabaseName = $db.Name
                                            User         = $User.Name
                                            Status       = "No matching login"
                                        }
                                    }
                                }
                            }

                            #With the collection complete invoke remove.
                            if ($RemoveNotExisting) {
                                if ($Force) {
                                    if ($Pscmdlet.ShouldProcess($db.Name, "Remove-DbaOrphanUser")) {
                                        Write-Message -Level Verbose -Message "Calling 'Remove-DbaOrphanUser' with -Force."
                                        Remove-DbaOrphanUser -SqlInstance $server -Database $db.Name -User $UsersToRemove -Force
                                    }
                                } else {
                                    if ($Pscmdlet.ShouldProcess($db.Name, "Remove-DbaOrphanUser")) {
                                        Write-Message -Level Verbose -Message "Calling 'Remove-DbaOrphanUser'."
                                        Remove-DbaOrphanUser -SqlInstance $server -Database $db.Name -User $UsersToRemove
                                    }
                                }
                            }
                        } else {
                            Write-Message -Level Verbose -Message "No orphan users found on database '$db'."
                        }
                        #reset collection
                        $UsersToWork = $null
                    } catch {
                        Stop-Function -Message $_ -Continue
                    }
                }
            } else {
                Write-Message -Level Verbose -Message "There are no databases to analyse."
            }
        }
    }
    end {
        Test-DbaDeprecation -DeprecatedOn "1.0.0" -EnableException:$false -Alias Repair-SqlOrphanUser
    }
}