On 9/27/06, Thomas L. Shinnick <[EMAIL PROTECTED]> wrote:
A doc patch for this to help people not get trapped by the stupidity of MySQL would be appreciated.
As you have said in a few more words, MySQL accepts both of the standard SQL syntaxes for declaring a relationship, but it silently ignores one of them. There's nothing the Loader can do about that, and certainly no sane user should expect the Loader to magically infer information that MySQL itself does not possess.
-- Brandon
Summary: need to document how to force SQL dialects to retain
relationship information, and have more 'foolproof' SQL examples.
I wanted to define my tables such that I'd be able to use
DBIC::Schema::Loader eventually. And so I wanted to be explicit in
relationships, such as "belongs_to".
So I coded up input to MySQL (4.1.18) that included
state_id INTEGER NOT NULL REFERENCES api_state_codes(id),
Then wanting to check that Schema::Loader would later be able to
'see' that description, I used "show create table" and was amazed to
see _nothing_, no mention at all of the relationship.
Peeking into Schema::Loader::DBI::mysql I saw it also used "show
create table" to retrieve information, but expected to see a fuller
form of the declaration. So I changed the code to read
state_id INTEGER NOT NULL,
FOREIGN KEY (state_id) REFERENCES api_state_codes(id),
and now "show create table" displayed
`state_id` int(11) NOT NULL default '0',
KEY `state_id` (`state_id`),
CONSTRAINT `api_county_codes_ibfk_1` FOREIGN KEY (`state_id`)
REFERENCES `api_state_codes` (`id`)
So at the very least the various DBIC::Schema::Loader::DBI::* modules
need to mention what is required to include relationship information
in SQL table creation sources.
And it would be good, where Schema::Loader is mentioned in the DBIC
docs, to remind that the relationships need to be explicit enough
that the particular SQL engine retains that information for
Schema::Loader to pick up later.
A doc patch for this to help people not get trapped by the stupidity of MySQL would be appreciated.
As you have said in a few more words, MySQL accepts both of the standard SQL syntaxes for declaring a relationship, but it silently ignores one of them. There's nothing the Loader can do about that, and certainly no sane user should expect the Loader to magically infer information that MySQL itself does not possess.
-- Brandon
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