mysql – 结果集是1个记录的对象,数组是多少？

我无法相信,但所有迹象都表明我的PowerShell代码返回SELECT查询的结果,该查询找到1条记录作为对象,但如果有两条或更多条记录,则相同的代码返回一个对象数组.我究竟做错了什么？

以下是代码：

function Connect-MySQL([string]$MySQLHost, [string]$user, [string]$pass, [string]$database) { 
    Write-Verbose "Connect-MySQL"
    # Load MySQL .NET Connector Objects 
    [void][system.reflection.Assembly]::LoadWithPartialName("MySql.Data") 

    # Open Connection 
    $connStr = "server=$MySQLHost;port=3306;uid=$user;pwd=$pass;database=$database;Pooling=FALSE" 
    try {
        $con = New-Object MySql.Data.MySqlClient.MySqlConnection($connStr) 
        $con.Open()
    } catch [System.Management.Automation.PSArgumentException] {
        Write-Verbose "Unable to connect to MySQL server, do you have the MySQL connector installed..?"
        Write-Verbose $_
        Exit
    } catch {
        Write-Verbose "Unable to connect to MySQL server..."
        Write-Verbose $_.Exception.GetType().FullName
        Write-Verbose $_.Exception.Message
        exit
    }
    Write-Verbose "Connected to MySQL database $MySQLHost\$database"

    return $con 
}

function Disconnect-MySQL($con) {
    Write-Verbose "Disconnect-MySQL"
    $con.Close()
}

function Execute-MySQLNonQuery($con, [string]$sql) { 
    $cmd = New-Object MySql.Data.MySqlClient.MySqlCommand($sql, $con)            # Create SQL command
    $Rows = $cmd.ExecuteNonQuery()                                               # Execute command
    $cmd.Dispose()                                                               # Dispose of command object
#   if ($Rows) { 
        return $Rows
#   } else { 
#       return $false 
#   } 
} 

function Execute-MySQLQuery($con, [string]$sql) { 
    $cmd = New-Object MySql.Data.MySqlClient.MySqlCommand($sql, $con)            # Create SQL command
    $dataAdapter = New-Object MySql.Data.MySqlClient.MySqlDataAdapter($cmd)      # Create data adapter from query command
    $dataSet = New-Object System.Data.DataSet                                    # Create dataset
    $dataAdapter.Fill($dataSet, "data") | Out-Null                               # Fill dataset from data adapter, with name "data"              
    $cmd.Dispose()                                                               # Dispose of command object
    return $dataSet.Tables["data"]                                               # Returns an array of results
}


# Connection Variables 
$MySQLHost = '10.10.10.111' 
$user = 'user' 
$pass = 'test' 
$database = 'test_db' 

# Connect to MySQL Database 
$con = Connect-MySQL $MySQLHost $user $pass $database

# Get requests
$sql = "
SELECT *
FROM o365_statuses as x
WHERE x.action = 'Z'
AND x.status = 0"
$result = Execute-MySQLQuery $con $sql

Write-Host $result.Count
Foreach ($r in $result) {
    write-host "$($r.id) $($r.email)"
}

当$result只有1条记录时,$result.Count不返回任何内容,我可以将这些列作为$result.id而不是$result [0] .id访问.如果返回2条或更多条记录则相反.

请告诉我,我做错了,这不是PowerShell的工作方式.

解决方法:

PowerShell基于这个简单的算法返回结果：

>多个项目 – >返回这些项的数组
>只有一个项目 – >退货

通常,强制PowerShell始终使用以下任一方法返回数组是一种好习惯：

,(code)
@(code)

但是,这些操作符并不完全相同！您可以安全地将@()分组运算符应用于强制数组输出的任何内容 – 数组始终具有Count属性,例如：

$a = @(Get-Process | select -First 2); $a.Count   # returns 2
$a = @(Get-Process | select -First 1); $a.Count   # returns 1

另一方面,逗号数组构造运算符的工作方式如下：

$a = ,(Get-Process | select -First 2); $a.Count   # returns 1
$a = ,(Get-Process | select -First 1); $a.Count   # returns 1

…因为它使用给定的任何内容构建嵌套数组.

标签：mysql,powershell,dataset,dataadapter
来源： https://codeday.me/bug/20190620/1247200.html