ExecuteReader () in Powershell script

Question

I am trying to read data from an SQL table in a powershell script. I see the data in the reader object, but reading it with the help While (readerobject.read()){}, it does not enter the loop.

Powershell

 $cmd = $sqlConn.CreateCommand()
 $cmd.CommandText ="SELECT * from user"
 $movedUserDetails = $cmd.ExecuteReader()
 while ($movedUserDetails.Read())
   {
      "[0] : " + $movedUserDetails.GetValue(0)
   }
 $movedUserDetails.Close() 

Answer 1

The syntax is correct, but you do nothing with the value once inside the loop. You want to persist. Here is an example of running some basic SQL inside powershell with two different types of commands (Text / SP) and two different execution methods (DataAdapter / DataReader). Any of them should work fine.

# config
$svr = "serverName"
$db = "databaseName"

# connection
$sqlConnection = New-Object System.Data.SqlClient.SqlConnection
$sqlConnection.ConnectionString = "Server=$svr;Database=$db;Integrated Security=True"
$sqlConnection.Open()

# command A - text
$sqlCmd = New-Object System.Data.SqlClient.SqlCommand
$sqlCmd.Connection = $sqlConnection
$sqlCmd.CommandText = "SELECT name AS TABLE_NAME FROM sys.tables"

# command B - stored procedure
$sqlCmd = New-Object System.Data.SqlClient.SqlCommand
$sqlCmd.Connection = $sqlConnection
$sqlCmd.CommandText = "sys.sp_tables"
$sqlCmd.CommandType = [System.Data.CommandType]::StoredProcedure
$sqlCmd.Parameters.Add("@table_owner", "dbo")

# execute A - data reader
$reader = $sqlCmd.ExecuteReader()
$tables = @()
while ($reader.Read()) {
    $tables += $reader["TABLE_NAME"]
}
$reader.Close()

# execute B - data adapter
$dataTable = New-Object System.Data.DataTable
$sqlAdapter = New-Object System.Data.SqlClient.SqlDataAdapter
$sqlAdapter.SelectCommand = $sqlCmd
$sqlAdapter.Fill($dataTable)
$sqlConnection.Close()

Answer 2

, . , SqlDataAdapter. Powershell SQL. .

function Invoke-SqlSelect
{
    [CmdletBinding()]
    Param
    ( 
        [ValidateNotNullOrEmpty()] 
        [Parameter(ValueFromPipeline=$True,Mandatory=$True)] 
        [string] $SqlServer,
        [Parameter(ValueFromPipeline=$True,Mandatory=$False)] 
        [string] $Database = "master",
        [ValidateNotNullOrEmpty()] 
        [Parameter(ValueFromPipeline=$True,Mandatory=$True)] 
        [string] $SqlStatement
    )
    $ErrorActionPreference = "Stop"

    $sqlConnection = New-Object System.Data.SqlClient.SqlConnection
    $sqlConnection.ConnectionString = "Server=$SqlServer;Database=$Database;Integrated Security=True"

    $sqlCmd = New-Object System.Data.SqlClient.SqlCommand
    $sqlCmd.CommandText = $SqlStatement
    $sqlCmd.Connection = $sqlConnection

    $sqlAdapter = New-Object System.Data.SqlClient.SqlDataAdapter
    $sqlAdapter.SelectCommand = $sqlCmd
    $dataTable = New-Object System.Data.DataTable
    try
    {
        $sqlConnection.Open()
        $sqlOutput = $sqlAdapter.Fill($dataTable)
        Write-Output -Verbose $sqlOutput
        $sqlConnection.Close()
        $sqlConnection.Dispose()
    }
    catch
    {
        Write-Output -Verbose "Error executing SQL on database [$Database] on server [$SqlServer]. Statement: `r`n$SqlStatement"
        return $null
    }


    if ($dataTable) { return ,$dataTable } else { return $null }
}

Answer 3

, , : ( ):

, , . , while. :

     $sqlConn.Open()
     $cmd = $sqlConn.CreateCommand()
     $cmd.CommandText ="SELECT * from user"
     $movedUserDetails = $cmd.ExecuteReader()
     try
     {
         while ($movedUserDetails.Read())
         {
           "[0] : " + $movedUserDetails.GetValue(0)
         }
     }
     catch
     {
       #log error
     }
     finally
     {
       $sqlConn.Close() 
     }

finally .

Answer 4

, SQL Server , Invoke-Sqlcmd Invoke-Sqlcmd. , , , .

, . , / , SqlConnection, SqlCommand SqlDataReader .

, PowerShell - , . , , DataTable , PowerShell " " (. [ScriptBlock]) IDataRecord IDataReader.

Invoke-SqlCommand : , , / ..

: PERSISTED SqlConnection , $ConnectionString $Connection.

function Invoke-SqlCommand {
  param(
    [Parameter(Mandatory=$True,
               ValueFromPipeline=$True,
               ValueFromPipelineByPropertyName=$True,
               HelpMessage="The connection string.")]
    [string] $ConnectionString,

    [Parameter(Mandatory=$True,
               HelpMessage="The query to run.")]
    [string] $Query,

    [Parameter(Mandatory=$True,
               HelpMessage="The work to perform against each IDataRecord.")]
    [scriptblock] $ScriptBlock
  )

  $conn = New-Object System.Data.SqlClient.SqlConnection
  $conn.ConnectionString = $ConnectionString

  $cmd = $conn.CreateCommand()
  $cmd.CommandText = $Query

  try {
    $conn.Open()
    $rd = $cmd.ExecuteReader()

    while($rd.Read()){
        Write-Output (Invoke-Command $ScriptBlock -ArgumentList $rd)
    }  
  } 
  finally {
    $conn.Close()
  }
}

, catch {...}, .

IDataRecord IDataRecord .

$connectionString = "your connection string"
$query = "SELECT * FROM users"
Invoke-SqlCommand $connectionString $query {
    param(
        [Parameter(Mandatory=$True)]
        [System.Data.SqlClient.SqlDataReader]$rd)

    $obj = New-Object -TypeName PSObject -Property @{ user_id = $rd.GetValue($rd.GetOrdinal("geoname_id"))}
    $obj.psobject.typenames.insert(0,'MyAwesome.Object')

    Write-Output $obj
}

New-Object , , -, PSObject , Get-Member.