Re: Wiele do wielu

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#82557

From: wloochacz
Date: Mon, 17 Aug 2015 17:23

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W dniu 2015-08-16 o 10:30, Borneq pisze:
> Jedna książka może mieć wielu autorów, jeden autor wiele książek. Oprócz
> tabel BOOKS i AUTHORS potrzebna tabela BOOKS_AUTHORS, ale jak to będzie
> wyglądało dla:
> book1 - auth1
> book2 - auth2,auth3
> book3 - auth1,auth3
> book4 - auth1,auth4
> book5 - auth2,auth3,auth4
>
> BOOKS ma 5 pozycji , AUTHORS 4 a BOOKS_AUTHORS?
Tak:

Create Table "Book"  (
	"IdBook" Integer NOT NULL,
  Primary Key ("IdBook")
);

Create Table "Author"  (
	"IdAuthor" Integer NOT NULL,
  Primary Key ("IdAuthor")
);

Create Table "BookAuthor"  (
	"IdBook" Integer NOT NULL,
	"IdAuthor" Integer NOT NULL,
  Primary Key ("IdBook","IdAuthor")
);

Alter Table "BookAuthor" add Foreign Key ("IdBook") references "Book" 
("IdBook") on update no action on delete cascade ;
Alter Table "BookAuthor" add Foreign Key ("IdAuthor") references 
"Author" ("IdAuthor") on update no action on delete cascade ;

-- 
wloochacz

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Subject: Re: Wiele do wielu
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Date: Mon, 17 Aug 2015 19:23:27 +0200
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