Re: Antw: many-many mapping between unique tables
От | Gerhard Dieringer |
---|---|
Тема | Re: Antw: many-many mapping between unique tables |
Дата | |
Msg-id | s9ead40a.069@kopo001 обсуждение исходный текст |
Ответ на | Antw: many-many mapping between unique tables ("Gerhard Dieringer" <DieringG@eba-haus.de>) |
Ответы |
Re: Antw: many-many mapping between unique tables
|
Список | pgsql-sql |
>>> Indraneel Majumdar <indraneel@www.cdfd.org.in> 16.10.2000 22.13 Uhr >>> > Yeah you understand the problem perfectly. The third table will definitely > contain unique entries if you take both x and y simultaneously. I wanted > some way of mapping where I would not need to repeat individual values of > x and y. I am not from a maths background and have absolutely no idea of > database design. > > Is it possible to map the columns without repeating values? > > \Indraneel I don't know what type of data your columns x and y contain. If they are, for example, of type text and contain long strings, then it would be better to add an integer id column in each tables T1 and T2: x_id and y_id and use these ids in the table T12. Then you only have to repeat the (short) numeric vales in T12. But I think there is no way to totaly avoid any repetition. -------------- Gerhard
В списке pgsql-sql по дате отправления: