Update-ConnectionString

Update-ConnectionString.ps1

function Update-ConnectionString {
    [CmdletBinding()]
    param(
        [Parameter(Mandatory = $true, ValueFromPipeline = $true)]
        [string[]] $ConnectionString,
        [Parameter(Mandatory = $true)]
        [string] $PropertyName,
        [Parameter(Mandatory = $true)]
        [string] $Value)
    begin {
        $PropertyName = Remove-WhiteSpace $PropertyName
        $Value = Remove-WhiteSpace $Value
    }
    process {
        ($ConnectionString |
            %{ $_ -split ';' } | 
            %{
                ($k, $v) = $_ -split '=' | Remove-WhiteSpace
        
                if ($k -eq $PropertyName) {
                    "$k=$Value"
                } else {
                    $_
                }
            }) -join ';'
    }
}