How do I execute a SELECT query against a SQLServer database and iterate results using PowerShell

Question

Say I have a table with 3 columns - "Column1", "Column2", and "Column3" - datatype is varchar(100) for all 3.

Using PowerShell, how do I connect to SQL Server and use SqlDataReader and ForEach operator to view the contents of "Column2"?

Answer 1

Here's roughly how I'm doing it:

$SqlServer = 'sql.example.com';
$SqlDatabase = 'MyDB';

$SqlConnectionString = 'Data Source={0};Initial Catalog={1};Integrated Security=SSPI' -f $SqlServer, $SqlDatabase;
$SqlQuery = "SELECT Name FROM dbo.Person ORDER BY Name;";

$SqlConnection = New-Object -TypeName System.Data.SqlClient.SqlConnection -ArgumentList $SqlConnectionString;
$SqlCommand = $SqlConnection.CreateCommand();
$SqlCommand.CommandText = $SqlQuery;

$SqlConnection.Open();
$SqlDataReader = $SqlCommand.ExecuteReader();

#Fetch data and write out to files
while ($SqlDataReader.Read()) {
    Write-Output $SqlDataReader['Name'];
}
$SqlConnection.Close();
$SqlConnection.Dispose();

If I remember right, I basically refactored the code from the MSDN example.

For those wondering why I'm using SqlDataReader: Most of my scripts use SqlDataAdapter, but this one retrieves about 8,000 PDFs from a database so I wasn't really interested in calling SqlDataAdapter.Fill(). In exchange for holding shared locks on the table much longer than SqlDataAdapter.Fill() would, SqlDataReader.Read() keeps memory usage down to a manageable level for the client by fetching one record at a time.