Peter Brawley wrote:
PJ,
As I understand it, I have one table books it lists all the info for
the book other than the author(s) or the categories ; for these I need
an authors table and a category table... I'll continue with the authors
as categories will surely be the same thing.
BTW, I
PJ
But what about foreign keys? Don't I need that to find the relationships
between the books, the authors and the categories? After all, isn't this
a relational db? If so, I can't use the default engine (MyISAM) which
does not support FK. So, if I have to use foreign keys, I have to change
to
Peter Brawley wrote:
PJ
But what about foreign keys? Don't I need that to find the relationships
between the books, the authors and the categories? After all, isn't this
a relational db? If so, I can't use the default engine (MyISAM) which
does not support FK. So, if I have to use foreign
PJ
PBEngine choice is another issue. InnoDB properly isolates FK
enforcement in the database. The MyISAM tradeoff (for speed) is that
you have to implement FK logic in code.
PJForgive my naiveté, but how do you do that?
You write application code to implement the equivalent of ON DELETE
PJ af.gour...@videotron.ca wrote on 02/10/2009 12:44:04 PM:
-- -
-- Table `books`
-- -
CREATE TABLE IF NOT EXISTS `books` (
`id` SMALLINT(4) UNSIGNED NOT NULL AUTO_INCREMENT ,
ddevaudre...@intellicare.com wrote:
PJ af.gour...@videotron.ca wrote on 02/10/2009 12:44:04 PM:
-- -
-- Table `books`
-- -
CREATE TABLE IF NOT EXISTS `books` (
`id` SMALLINT(4)
Just about the authors
You need a separate table for them and then an table linking authors and
books.
So you have table books, authors and rel_books_authors where rel_books
authors has 3 entries for a book with 3 authors just using the book id and
the author is's
Olaf
On 2/9/09 10:25 AM, PJ
Olaf Stein wrote:
Just about the authors
You need a separate table for them and then an table linking authors and
books.
You lose me here... :-(
Why do I need a third table?
I may have 2 or three books with 3 authors, quite a few with 2 authors
and many with just 1 author.
I can't see
PJ
Why do I need a third table?
The clue is author (could be 2 or more) in your books column list. It
is incorrect to store two author names or IDs in one column. The
relationship is 1:many. So you need a bridge table:
books(id PK, etc...)
authors(id PK, etc...)
books_authors(id PK, bid
See normalization...
You don't need to do this but it is considered good practice for many
reasons
On 2/9/09 12:04 PM, Peter Brawley peter.braw...@earthlink.net wrote:
PJ
Why do I need a third table?
The clue is author (could be 2 or more) in your books column list. It
is incorrect to
Peter Brawley wrote:
PJ
Why do I need a third table?
The clue is author (could be 2 or more) in your books column list.
It is incorrect to store two author names or IDs in one column. The
relationship is 1:many. So you need a bridge table:
books(id PK, etc...)
authors(id PK, etc...)
Book table:
book id : 1, name: some book name
Author table
Author id: 1, name: author 1
Author id: 2, name: author 2
Rel_author_book table:
Book id: 1, author id: 1
Book id: 1, author id: 2
Same with categories and other 1:N relations
Olaf
On 2/9/09 2:01 PM, PJ af.gour...@videotron.ca
PJ,
As I understand it, I have one table books it lists all the info for
the book other than the author(s) or the categories ; for these I need
an authors table and a category table... I'll continue with the authors
as categories will surely be the same thing.
BTW, I cannot use ISBN as
PK since
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