public int Delete(Course course)
{
string sql = $"delete from Course where CourseId={course.CourseId}";
return(SQLHelper.ExecuteNonQuery(sql));
}
public int Update(Course course)
{
string sql = $"update Course set CourseContent='{course.CourseContent}' where CourseId={course.CourseId}";
return(SQLHelper.ExecuteNonQuery(sql));
}