PnP power shell script code to connect the SQL database and get the data into dataset

I am getting the data into the data-reader after connecting and getting the data from SQL database table. Instead-of this I want to load the data into the data table or dataset so that I can close the SQL connection ($connection.Close()) to improve the performance.

My present code for your reference below :-

$command = New-Object System.Data.SqlClient.SqlCommand($query, $connection)
$reader = $command.ExecuteReader()

while ($reader.Read())
{
for ($i = 0; $i -lt $Reader.FieldCount; $i++)
{

$SourceSiteUrl = $Reader.GetValue(0)
$TargetSiteUrl =$Reader.GetValue(1)

}

}

}
catch
{
Write-Host "Update exception msg " $_.Exception.Message
}
finally
{
$connection.Close()
}