How to insert record into a table and get result to insert in another table using LINQ

Question

I would like to insert two records into two tables where result of first insert needs the second insert. Now it not working correctly because it return SQL exception with foreign key.

The INSERT statement conflicted with the FOREIGN KEY constraint "FK_VacancyLog_Vacancy". The conflict occurred in database "mydb", table "dbo.Vacation", column 'Id'. The statement has been terminated.

How to fix it?

using (var transaction = this.Context.Database.BeginTransaction())
{
    var result = this.Context.Vacancy.Add(vacancy);
    this.Context.SaveChanges();

    var vacancyLog = new VacancyLog()
    {
        Status = 1,
        ModificationDate = DateTime.Now(),
        VacancyId = result.Id
    };
    this.Context.VacancyLog.Add(vacancyLog);
    this.Context.SaveChanges();

    transaction.Commit();
}