c# - Check the existence of a record before inserting a new record

Question

I'm using the Ado.net Entity Framework for the first time and I need to check if this record exist before I insert it to the database. Preferably I'd search if AuthodSSID exists and not the key (AuthorID). I'm using VS2010, Framework 4. System.Data.Entity is 3.5.0.0.

I googled, but found no answer for this question.

PublishingCompanyEntities publishContext;
publishContext = new PublishingCompanyEntities();

private void createNew_Click(object sender, EventArgs e)
{
    Author newAuthor = new Author();
    newAuthor.FirstName = firstName.Text;
    newAuthor.LastName = lastName.Text;
    newAuthor.AuthodSSID = 20;
    newAuthor.AuthorID = 10
//Check if record exist here
    publishContext.AddToAuthor(newAuthor);//insert if does not exist

}

Answer 1

The only way to check if a record exists is to query the record and see if anything comes back:

var existingAuthorCount = publishContext.Author.Count(a => a.AuthodSSID == 20);
if (existingAuthorCount == 0) 
{
    // Do your insert
}