Question

In timing our code, I noticed that there is a substantial transaction time each time Linq communicates with SQL Server. In the past, when we used SQL directly, we could place multiple statements and send it at once. Is there a way to do this in Linq? In particular, I have two tables, a Log table and a UHAs (userhostaddress) table. If the uha is not already in the UHAs table, it must be inserted, and then the Log entry made with the uhaid. In Linq, this takes three calls, once to verify that the uha does not exist, once to insert it, and once for the log. Can I do this in one call to the database?

    var uha = db.UHAs.Where(u => u.userhostaddress == _userHostAddress).FirstOrDefault();
    if (uha == null)
    {
        var newUha = new UHA()
        {
            userhostaddress = _userHostAddress
        };
        db.UHAs.InsertOnSubmit(newUha);
        db.SubmitChanges();     // 2. Second call

        uha = newUha;
    }

    SHA1 sha1 = SHA1.Create();
    var newLog= new Log()
    {                    
        requested = DateTime.UtcNow,
        uhaid = uha.uhaid,
        query = _query,
        queryhash = sha1.ComputeHash(Encoding.UTF8.GetBytes(_query))
    };
    db.Log.InsertOnSubmit(newLog);
    db.SubmitChanges();

Answer 1

Since you are using the same instance of the data context you only need to call SubmitChanges() once. That will execute all commands at once rather than making multiple trips to the sql server.