I don’t know about you, but using the SSMS GUI tool to restore a bunch of transaction logs is very tedious. I’ve got another number of large databases which will require mirroring also. With this in mind, I decided it would be beneficial to have a script to automate the process. What was of interest to me was being able to iterate through the process several times while copying new transaction logs. The script will process all the transaction logs in a directory at one time. If you happen to generate more transaction logs to the directory and run the script again, you will get error messages for the logs already restored but the new logs will still be restored.

The script also takes into account using UNC paths. So, you can run the script from any machine against an SQL Server on a remote machine.

 Restore-TransLogs.ps1 -server "MYSERVER\MYSQL" -database "MY_Database"
	.NOTES
		AUTHOR:    John P. Wood
		CREATED:   September, 2011
		VERSION:   1.0.0
#>
Param(
	[Parameter(Mandatory=$true)]
	[string]$Server,
	[Parameter(Mandatory=$true)]
	[string]$database,
	[Parameter(Mandatory=$true)]
	[string]$FilePath
	)
Set-StrictMode -Version Latest
[Void][System.Reflection.Assembly]::LoadWithPartialName("Microsoft.SqlServer.ConnectionInfo")
[Void][System.Reflection.Assembly]::LoadWithPartialName("Microsoft.SqlServer.SMO")
[Void][System.Reflection.Assembly]::LoadWithPartialName("Microsoft.SqlServer.SmoExtended")

## SQL Server Backup\Restore uses local file paths.
Function Get-LocalPath($File) {
	$dir = $File.DirectoryName
	$rp = $dir.Remove(0,($dir.IndexOf('$')+2))
	$root = (((Get-Item $dir).Root).Name).Replace('$',':')
	$local = $root + '\' + $rp + '\' + $File
	$local
}
Function New-SMOconnection {
    Param (
		[string]$server
	)
	$conn = New-Object Microsoft.SqlServer.Management.Common.ServerConnection($server)
	$conn.applicationName = "PowerShell SMO"
	$conn.StatementTimeout = 0
	$conn.Connect()
	if ($conn.IsOpen -eq $false) {
		Throw "Could not connect to server $($server)"
	}
	$smo = New-Object Microsoft.SqlServer.Management.Smo.Server($conn)
	$smo
}
Function Invoke-SqlRestore {
	Param(
		[string]$filename
	)
	# Get a new connection to the server
    $backupDevice = New-Object("Microsoft.SqlServer.Management.Smo.BackupDeviceItem") ($filename, "File")

	# Load up the Restore object settings
	$Restore = new-object Microsoft.SqlServer.Management.Smo.Restore
	$Restore.Action = [Microsoft.SqlServer.Management.Smo.RestoreActionType]::Log
	$Restore.Database = $database
    $Restore.NoRecovery = $true
	$Restore.Devices.Add($backupDevice)

	$Restore.SqlRestore($smo)
}
Clear-Host
$smo = New-SMOconnection -server $Server
If(!(Test-Path -LiteralPath $FilePath)){Throw "FilePath not found: $FilePath"}
Get-ChildItem $FilePath -Filter "*.trn" | Sort-Object -Property LastWriteTime |
	ForEach-Object {
		If(($_.Fullname).StartsWith('\\')) {$file = Get-LocalPath $_ }
		Else {$file = $_.FullName}
		Try {Invoke-SqlRestore -filename $file}
		Catch {
			$ex = $Error[0].Exception
			Write-Output $ex.message
			while ($ex.InnerException)
			{
				$ex = $ex.InnerException
				Write-Output $ex.message
			}
		}
}
If ($smo.ConnectionContext.IsOpen -eq $true) {$smo.ConnectionContext.Disconnect()}

Using Powershell and a simple script to execute Sp_Cycle_Errorlog, I now have a weekly, Windows scheduled task which executes the sproc to cycle the logs for all my SQL Servers.

foreach ($svr in get-content D:\Scripts\Servers.TXT ){
    $svr
    Invoke-Expression 'SQLCMD -E -S $svr -Q "Exec Sp_Cycle_Errorlog"' | Out-Null
	}

I found a good PowerShell script for backing up databases at this blog location. However, I wanted to change it slightly to accommodate backing up ALL, System, User, or a list of databases. Processing ALL, System, or User is straightforward enough but I had to it was the first time I came up against have to compare a value against a list of values. In SQL you simply use an IN operator with a list of values but I was not sure of how to accomplish the same process in PowerShell.

Here was my problem: the user could supply a list of databases to backup and the backup script has a line with captures all the database objects for that SQL Server instance. I need to backup only those which are in the users list.

I found that the PowerShell WHERE clause can use a -contains operator which effectively filters the selection for an array. To test the operation I set up a small script to build two arrays and then I piped one array through a WHERE filter of which the results are piped to a ForEach. The ForEach sees only the results of the WHERE which mimics the SQL IN operator.

Run this code in PowerShell to see what I mean.

$a = @("db1","db2","db3","db4")
$d = @("db1","db2","db3","db4","db5","db6","db7","db8")
$d | where { $a -contains $_ } | foreach { Write-Host $_ }

$a represents the list of database supplied by the user.
$d represents the array of databases returned when accessing the Microsoft.SqlServer.Management.Smo.Server object.
I can now back up the user supplied databases within the foreach script block.

Tips & Tricks Using Compare-Object – Dreaming in PowerShell – PowerShell.com

I am very new to PowerShell but I am beginning to like using it considerably more each day. I recently had a need for a quick and easy way to script a process which would copy only new files from one location to another. after scouring the Internet for a good example, I stumbled upon the Compare-Object cmdlet and this excellent article.

The actual script I came up with is rather simple and serves my purpose exactly. As I  mentioned, I am new to PowerShell and there may very well be a better method. However, this one works for me.

The script code:

param(
    [string]$s = '\\serverx\c$\ProgramData\Polaris\3.5\SQLVS1\AuthorityUpdates',
    [string]$t = '\\servery\data03\shared\libraries\zmarc'
)

$target = Get-ChildItem $t
$source = get-childitem $s
Compare-Object $source $target -Property Name -PassThru |
    Where-Object { $_.SideIndicator -eq '<=' } |
    foreach-object -process{
        copy-item $_.FullName -destination $t
        }

Why Visual Studio targets only one version of the .NET Framework