functions/Test-DbaDatabaseCollation.ps1

function Test-DbaDatabaseCollation {
    <#
    .SYNOPSIS
        Compares Database Collations to Server Collation
 
    .DESCRIPTION
        Compares Database Collations to Server Collation
 
    .PARAMETER SqlInstance
        The SQL Server that you're connecting to.
 
    .PARAMETER Credential
        Credential object used to connect to the SQL Server as a different user
 
    .PARAMETER Database
        The database(s) to process - this list is auto-populated from the server. If unspecified, all databases will be processed.
 
    .PARAMETER ExcludeDatabase
        The database(s) to exclude - this list is auto-populated from the server
 
    .PARAMETER Detailed
        Shows detailed information about the server and database collations
 
    .NOTES
        Website: https://dbatools.io
        Copyright: (C) Chrissy LeMaire, clemaire@gmail.com
        License: GNU GPL v3 https://opensource.org/licenses/GPL-3.0
 
    .LINK
        https://dbatools.io/Test-DbaDatabaseCollation
 
    .EXAMPLE
        Test-DbaDatabaseCollation -SqlInstance sqlserver2014a
 
        Returns server name, databse name and true/false if the collations match for all databases on sqlserver2014a
 
    .EXAMPLE
        Test-DbaDatabaseCollation -SqlInstance sqlserver2014a -Database db1, db2
 
        Returns server name, databse name and true/false if the collations match for the db1 and db2 databases on sqlserver2014a
 
    .EXAMPLE
        Test-DbaDatabaseCollation -SqlInstance sqlserver2014a, sql2016 -Detailed -Exclude db1
 
        Lots of detailed information for database and server collations for all databases except db1 on sqlserver2014a and sql2016
 
    .EXAMPLE
        Get-DbaRegisteredServer -SqlInstance sql2016 | Test-DbaDatabaseCollation
 
        Returns db/server collation information for every database on every server listed in the Central Management Server on sql2016
    #>

    [CmdletBinding()]
    [OutputType("System.Collections.ArrayList")]
    Param (
        [parameter(Mandatory = $true, ValueFromPipeline = $true)]
        [Alias("ServerInstance", "SqlServer")]
        [DbaInstanceParameter[]]$SqlInstance,
        [PSCredential]
        $Credential,
        [Alias("Databases")]
        [object[]]$Database,
        [object[]]$ExcludeDatabase,
        [switch]$Detailed
    )

    begin {
        $collection = New-Object System.Collections.ArrayList

    }

    process {
        foreach ($servername in $SqlInstance) {
            try {
                $server = Connect-SqlInstance -SqlInstance $servername -SqlCredential $Credential
            }
            catch {
                if ($SqlInstance.count -eq 1) {
                    throw $_
                }
                else {
                    Write-Warning "Can't connect to $servername. Moving on."
                    Continue
                }
            }

            $dbs = $server.Databases

            if ($Database) {
                $dbs = $dbs | Where-Object { $Database -contains $_.Name }
            }

            if ($ExcludeDatabase) {
                $dbs = $dbs | Where-Object Name -NotIn $ExcludeDatabase
            }

            foreach ($db in $dbs) {
                Write-Verbose "Processing $($db.name) on $servername"
                $null = $collection.Add([PSCustomObject]@{
                        Server            = $server.name
                        ServerCollation   = $server.collation
                        Database          = $db.name
                        DatabaseCollation = $db.collation
                        IsEqual           = $db.collation -eq $server.collation
                    })
            }
        }
    }

    end {
        if ($detailed) {
            return $collection
        }

        if ($Database.count -eq 1) {
            if ($SqlInstance.count -eq 1) {
                return $collection.IsEqual
            }
            else {
                return ($collection | Select-Object Server, isEqual)
            }
        }
        else {
            return ($collection | Select-Object Server, Database, IsEqual)
        }
    }
}