I need to write a simple C# .NET application to retrieve, update, and insert some data in a Sharepoint list.

I am NOT a Sharepoint developer, and I don't have control over our Sharepoint server. I would prefer not to have to develop this in a proper sharepoint development environment simply because I don't want to have to deploy my application on the Sharepoint server -- I'd rather just access data externally.

Anyway, I found out that you can access Sharepoint data using OLE DB, and I tried it successfully using some ADO.NET:

var db = DatabaseFactory.CreateDatabase();
DataSet ds = new DataSet();
using (var command = db.GetSqlStringCommand("SELECT * FROM List"))
{
    db.LoadDataSet(command, ds, "List");
}

The above works.

However, when I try to insert:

using (var command = db.GetSqlStringCommand("INSERT INTO List ([HeaderName],
    [Description], [Number]) VALUES ('Blah', 'Blah', 100)"))
{
    db.ExecuteNonQuery(command);
}

I get this error:

Cannot update 'HeaderName'; field not updateable.

I did some Googling and apparently you cannot insert data through OLE DB!

Does anyone know if there are some possible workarounds?

I could try using Sharepoint Web Services, but I tried that initially and was having a heck of a time authenticating. Is that my only option?