Inheritance: INotifyPropertyChanging, INotifyPropertyChanged
        /// <summary>
        /// function that adds a keyword to the specified dictionary
        /// </summary>
        /// <param name="dictionary">dictionary to add keyword to</param>
        /// <param name="phrase">the phrase to add to the dictionary specified</param>
        /// <param name="slide_num">the number of the slide</param>
        public void addKeyword(string dictionary, string phrase, int slide_num)
        {
            using (var db = new PlanetariumDataContext())
            {
                Dictionary cat = db.Dictionaries.Single(a => a.Type.Equals(dictionary));
                Keyword key = new Keyword { Dictionary_ID = cat.Dictionary_ID, Phrase = phrase, Slide_Num = slide_num };

                db.Keywords.InsertOnSubmit(key);
                db.SubmitChanges();

            }
        }
 partial void DeleteKeyword(Keyword instance);
 partial void InsertKeyword(Keyword instance);
 partial void UpdateKeyword(Keyword instance);
		private void detach_Keywords(Keyword entity)
		{
			this.SendPropertyChanging();
			entity.Dictionary = null;
		}