functions/Copy-SqlDatabaseAssembly.ps1

Function Copy-SqlDatabaseAssembly
{
<#
.SYNOPSIS
Copy-SqlDatabaseAssembly migrates assemblies from one SQL Server to another.

.DESCRIPTION
By default, all assemblies are copied. The -Assemblies parameter is autopopulated for command-line completion and can be used to copy only specific assemblies.

If the assembly already exists on the destination, it will be skipped unless -Force is used.
    
This script does not yet copy dependents.

.PARAMETER Source
Source SQL Server.You must have sysadmin access and server version must be SQL Server version 2000 or greater.

.PARAMETER Destination
Destination Sql Server. You must have sysadmin access and server version must be SQL Server version 2000 or greater.

.PARAMETER SourceSqlCredential
Allows you to login to servers using SQL Logins as opposed to Windows Auth/Integrated/Trusted. To use:

$scred = Get-Credential, then pass $scred object to the -SourceSqlCredential parameter.

Windows Authentication will be used if DestinationSqlCredential is not specified. SQL Server does not accept Windows credentials being passed as credentials.
To connect as a different Windows user, run PowerShell as that user.

.PARAMETER DestinationSqlCredential
Allows you to login to servers using SQL Logins as opposed to Windows Auth/Integrated/Trusted. To use:

$dcred = Get-Credential, then pass this $dcred to the -DestinationSqlCredential parameter.

Windows Authentication will be used if DestinationSqlCredential is not specified. SQL Server does not accept Windows credentials being passed as credentials.
To connect as a different Windows user, run PowerShell as that user.

.NOTES
Author: Chrissy LeMaire (@cl), netnerds.net
Requires: sysadmin access on SQL Servers

dbatools PowerShell module (https://dbatools.io, clemaire@gmail.com)
Copyright (C) 2016 Chrissy LeMaire

This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>.

.LINK
http://dbatools.io/Get-SqlDatabaseAssembly

.EXAMPLE
Copy-SqlDatabaseAssembly -Source sqlserver2014a -Destination sqlcluster

Copies all assemblies from sqlserver2014a to sqlcluster, using Windows credentials. If assemblies with the same name exist on sqlcluster, they will be skipped.

.EXAMPLE
Copy-SqlDatabaseAssembly -Source sqlserver2014a -Destination sqlcluster -Assemblies dbname.assemblyname, dbname3.anotherassembly -SourceSqlCredential $cred -Force

Copies two assemblies, the dbname.assemblyname and dbname3.anotherassembly, from sqlserver2014a to sqlcluster, using SQL credentials for sqlserver2014a
and Windows credentials for sqlcluster. If a assembly with the same name exists on sqlcluster, it will be dropped and recreated because -Force was used.
    
In this example, anotherassembly will be copied to the dbname3 database on the server "sqlcluster".
    
.EXAMPLE
Copy-SqlThing -Source sqlserver2014a -Destination sqlcluster -WhatIf -Force

Shows what would happen if the command were executed using force.
#>

    [CmdletBinding(DefaultParameterSetName = "Default", SupportsShouldProcess = $true)]
    param (
        [parameter(Mandatory = $true)]
        [object]$Source,
        [parameter(Mandatory = $true)]
        [object]$Destination,
        [System.Management.Automation.PSCredential]$SourceSqlCredential,
        [System.Management.Automation.PSCredential]$DestinationSqlCredential,
        [switch]$Force
    )
    DynamicParam { if ($source) { return (Get-ParamSqlDatabaseAssemblies -SqlServer $Source -SqlCredential $SourceSqlCredential) } }
    
    BEGIN 
    {
    
    $assemblies = $psboundparameters.Assemblies
        
        $sourceserver = Connect-SqlServer -SqlServer $Source -SqlCredential $SourceSqlCredential
        $destserver = Connect-SqlServer -SqlServer $Destination -SqlCredential $DestinationSqlCredential
        
        $source = $sourceserver.DomainInstanceName
        $destination = $destserver.DomainInstanceName
        
        if ($sourceserver.versionMajor -lt 9 -or $destserver.versionMajor -lt 9)
        {
            throw "Assemblies are only supported in SQL Server 2005 and above. Quitting."
        }
    
    }
    PROCESS
    {
        
        $sourceassemblies = @()
        foreach ($database in $sourceserver.Databases)
        {
            try
            {
                # a bug here requires a try/catch
                $userassemblies = $database.assemblies | Where-Object { $_.isSystemObject -eq $false }
                foreach ($assembly in $userassemblies)
                {
                    $sourceassemblies += $assembly
                }
            }
            catch { }
        }
        
        $destassemblies = @()
        foreach ($database in $destserver.Databases)
        {
            try
            {
                # a bug here requires a try/catch
                $userassemblies = $database.assemblies | Where-Object { $_.isSystemObject -eq $false }
                foreach ($assembly in $userassemblies)
                {
                    $destassemblies += $assembly
                }
            }
            catch { }
        }
        
        foreach ($assembly in $sourceassemblies)
        {
            $assemblyname = $assembly.Name
            $dbname = $assembly.Parent.Name
            $destdb = $destserver.Databases[$dbname]
            
            if ($destdb -eq $null) { Write-Warning "Destination database $dbname does not exist. Skipping $assemblyname.";  continue }
            if ($assemblies.length -gt 0 -and $assemblies -notcontains "$dbname.$assemblyname") { continue }
            
            if ($assembly.AssemblySecurityLevel -eq "External" -and $destdb.Trustworthy -eq $false)
            {
                If ($Pscmdlet.ShouldProcess($destination, "Setting $dbname to External"))
                {
                    Write-Warning "Setting $dbname Security Level to External on $destination"
                    $sql = "ALTER DATABASE $dbname SET TRUSTWORTHY ON"
                    try
                    {
                        $destserver.ConnectionContext.ExecuteNonQuery($sql) | Out-Null
                    }
                    catch { Write-Exception $_ }
                }
            }
            
            
            if ($destserver.Databases[$dbname].Assemblies.Name -contains $assembly.name)
            {
                if ($force -eq $false)
                {
                    Write-Warning "Assembly $assemblyname exists at destination in the $dbname database. Use -Force to drop and migrate."
                    continue
                }
                else
                {
                    If ($Pscmdlet.ShouldProcess($destination, "Dropping assembly $assemblyname and recreating"))
                    {
                        try
                        {
                            Write-Output "Dropping assembly $assemblyname"
                            Write-Output "This won't work if there are dependencies."
                            $destserver.Databases[$dbname].Assemblies[$assemblyname].Drop()
                            Write-Output "Copying assembly $assemblyname"
                            $destserver.Databases[$dbname].ExecuteNonQuery($assembly.Script()) | Out-Null
                        }
                        catch { 
                            Write-Exception $_ 
                            continue
                        }
                    }
                }
            }
            
            If ($Pscmdlet.ShouldProcess($destination, "Creating assembly $assemblyname"))
            {
                try
                {
                    Write-Output "Copying assembly $assemblyname from database."
                    $destserver.Databases[$dbname].ExecuteNonQuery($assembly.Script()) | Out-Null
                }
                catch
                {
                    Write-Exception $_
                }
            }
        }
    }
    
    END
    {
        $sourceserver.ConnectionContext.Disconnect()
        $destserver.ConnectionContext.Disconnect()
        If ($Pscmdlet.ShouldProcess("console", "Showing finished message")) { Write-Output "Assembly migration finished" }
    }
}