无法验证参数“用户名”上的参数参数为null或为空提供一个不为null或为空的参数

问题描述

我正在尝试使用Powershell 7-Preview执行Powershell脚本（7.0）文件，该文件将遍历所有数据库并在所有DB中执行sql Server脚本。

该脚本可以正确提取所有数据库，但是，在执行Parallel块时，出现此错误（请查找下面的屏幕截图以获取详细信息）。

无法验证参数“用户名”上的参数。参数为null或为空。提供一个不为null或为空的参数，然后重试该命令。

命令-C：\ GitHub \ TempApp \ CompanyTemplate \ bin \ debug \ DeploymentScripts \ PowerShell \ DeployCompanyDatabases.ps1

Param
(
    [string]$SystemWorkingDir,[string]$DatabaseUsername,[string]$DatabasePassword,[string]$DacpacLocation,[string]$OngoingChangesScriptLocation,[string]$PreDeploymentBugFixScriptLocation,[string]$DropExternalTablesScriptLocation
)

    $SystemWorkingDir = "C:\GitHub\TempAPP\CompanyTemplate\bin\Debug" 
    $DatabaseUsername = "tempDB"
    $DatabasePassword = "tempPassword" 
    $DacpacLocation = "CompanyTemplate.dacpac" 
    $OngoingChangesScriptLocation = "DeploymentScripts\OnGoingDataChanges.sql" 
    $PreDeploymentBugFixScriptLocation = "DeploymentScripts\PreDeployment.sql"
    $DropExternalTablesScriptLocation = "DeploymentScripts\DropExternalTables.sql"
    [string]$ServerInstance = "tempDB"

$GetDatabasesParams = @{
    "Database" = "master"
    "ServerInstance" =  "tempDB"
    "Username" = "$DatabaseUsername"
    "Password" = "$DatabasePassword"
    "Query" = "select [name] from sys.databases where [name] like 'Company%'"
    "ConnectionTimeout" = 9999
}

echo "Retrieving company database names"
[string[]]$DatabaseNames = Invoke-sqlcmd @GetDatabasesParams | select -expand name

[int]$ErrorCount = 0
$DatabaseNames | ForEach-Object -Parallel {
    try 
    {
        $OngoingChangesScriptParams = @{
            "Database" = "$_"
            "ServerInstance" = "$ServerInstance"
            "Username" = "$DatabaseUsername"
            "Password" = "$DatabasePassword"
            "InputFile" ="$SystemWorkingDir\$OngoingChangesScriptLocation" 
            "OutputsqlErrors" = 1
            "QueryTimeout" = 9999
            "ConnectionTimeout" = 9999
        }

        Invoke-sqlcmd @OngoingChangesScriptParams       
    }
    catch
    {
        $ErrorCount++
        echo "Internal Error. The remaining databases will still be processed."
        echo $_.Exception|Format-List -force
    }
}

错误：

解决方法

此问题并非完全等同于Send string parameters to a Start-Job script block，但答案与https://stackoverflow.com/a/63702220/3156906..几乎相同。

问题在于，$DatabaseUsername脚本块中的$DatabasePassword和foreach-object等变量在不同的范围内，并且实际上是与主脚本中的变量不同的变量。

您可以使用Using scope modifier

来解决此问题

对于在会话外执行的任何脚本或命令，您需要使用“作用域”修饰符从调用会话作用域中嵌入变量值，以便会话外代码可以访问它们。

所以代替：

$DatabaseUsername = "myusername"

foreach-object -parallel {
    ...
    "Username" = $DatabaseUsername
    ...
}

尝试

$DatabaseUsername = "myusername"

foreach-object -parallel {
    ...
    "Username" = $using:DatabaseUsername
    ...
}

powershell powershell-7.0