Re: [RDBO] Sequence Support
On Mar 20, 2007, at 7:02 PM, Jud wrote: > On 20/03/07 18:57 -0400, Jonathan Vanasco <[EMAIL PROTECTED]> wrote: >> ok. its on my list right after the debugger module :) > > If you're actually putting together a debug module, I'd put in a > request > for a simple way to turn on all debugging in Rose... Like via an > environment variable, or using Log::Log4perl, etc... a lot of stuff like that already exists just about every rose class has our $Debug= 0; ie: $Rose::DB::Object::Manager::Debug= 1 will print a lot of neat stuff to stderr. i've just been sketching out a customized debug class, so objects can inherit from it and have internal debugging. - Take Surveys. Earn Cash. Influence the Future of IT Join SourceForge.net's Techsay panel and you'll get the chance to share your opinions on IT & business topics through brief surveys-and earn cash http://www.techsay.com/default.php?page=join.php&p=sourceforge&CID=DEVDEV ___ Rose-db-object mailing list Rose-db-object@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/rose-db-object
Re: [RDBO] Sequence Support
On 20/03/07 18:57 -0400, Jonathan Vanasco <[EMAIL PROTECTED]> wrote: > ok. its on my list right after the debugger module :) If you're actually putting together a debug module, I'd put in a request for a simple way to turn on all debugging in Rose... Like via an environment variable, or using Log::Log4perl, etc... - Take Surveys. Earn Cash. Influence the Future of IT Join SourceForge.net's Techsay panel and you'll get the chance to share your opinions on IT & business topics through brief surveys-and earn cash http://www.techsay.com/default.php?page=join.php&p=sourceforge&CID=DEVDEV ___ Rose-db-object mailing list Rose-db-object@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/rose-db-object
Re: [RDBO] Sequence Support
On Mar 20, 2007, at 3:27 PM, John Siracusa wrote: > Well then code it up and send it to me :) ok. its on my list right after the debugger module :) > That level abstraction is > not strictly necessary to support the proposed feature (columns that > are not part of the PK but that have default values pulled from > sequences), but it might be useful nonetheless. right -- but if you're handling a large db with a lot of inter- related tables, being able to access sequences directly is really helpful. >> getting that to work with all dbs might be a pain though. > > Not really. If you decide to do it, you'd delegate all db-specific > functionality to the "db" (Rose::DB) object. As mentioned earlier in > this thread, there's already a vaguely cross-db-compatible > next_value_in_sequence() method in Rose::DB. You'd just have to add > more such methods. The Rose::DB::Sequence class wouldn't have any > db-specific code in it at all. well yes, but there would need to be a lot of conditionals in that module / the db specific drivers to implement the operations. i'll still have to write them somewhere. // Jonathan Vanasco | - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - | SyndiClick.com | - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - | FindMeOn.com - The cure for Multiple Web Personality Disorder | Web Identity Management and 3D Social Networking | - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - | RoadSound.com - Tools For Bands, Stuff For Fans | Collaborative Online Management And Syndication Tools | - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - Take Surveys. Earn Cash. Influence the Future of IT Join SourceForge.net's Techsay panel and you'll get the chance to share your opinions on IT & business topics through brief surveys-and earn cash http://www.techsay.com/default.php?page=join.php&p=sourceforge&CID=DEVDEV ___ Rose-db-object mailing list Rose-db-object@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/rose-db-object
Re: [RDBO] Sequence Support
On 3/20/07, Jonathan Vanasco <[EMAIL PROTECTED]> wrote: > I'd actually like to see sequence classes > Rose::DB::Object::Metadata::Sequence > > Which lets us map sequences to rose objects , and vice versa > > I'd like to be able to call > > my $seq= MyApp::Rose::DB::Object::Sequence1->new(); > my $curval= $seq->curval; > my $nextval= $seq->nextval; > my $lastval = $seq->lastval; Well then code it up and send it to me :) That level abstraction is not strictly necessary to support the proposed feature (columns that are not part of the PK but that have default values pulled from sequences), but it might be useful nonetheless. > getting that to work with all dbs might be a pain though. Not really. If you decide to do it, you'd delegate all db-specific functionality to the "db" (Rose::DB) object. As mentioned earlier in this thread, there's already a vaguely cross-db-compatible next_value_in_sequence() method in Rose::DB. You'd just have to add more such methods. The Rose::DB::Sequence class wouldn't have any db-specific code in it at all. -John - Take Surveys. Earn Cash. Influence the Future of IT Join SourceForge.net's Techsay panel and you'll get the chance to share your opinions on IT & business topics through brief surveys-and earn cash http://www.techsay.com/default.php?page=join.php&p=sourceforge&CID=DEVDEV ___ Rose-db-object mailing list Rose-db-object@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/rose-db-object
Re: [RDBO] Sequence Support
Derek Watson wrote:
>
> Hello,
>
> Is it possible to get sequence support in RDBO? I know that sequences
> are supported for primary key generation, but I have a few cases where
> they are used for non-keyed columns, and I find myself writing (and
> re-writing) this into my classes:
>
> sub insert {
>
> my $self = shift;
>
> unless ($self->some_sequence_column) {
>
> $self->some_sequence_column($self->db->next_value_in_sequence('some_seq'));
> }
>
> return $self->SUPER::insert(@_);
> }
>
> But since next_value_in_sequence is not documented, I am worrying that
> it's interface may change or disappear. Please correct me if I have
> missed something.
>
> Derek
Here's a perspective on sequences from the best database you never heard of:
http://www.oracle.com/technology/products/rdb/pdf/0307_sequences.pdf
Cheers,
jec
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Re: [RDBO] Sequence Support
On Mar 20, 2007, at 12:48 PM, John Siracusa wrote:
> On 3/20/07, Derek Watson <[EMAIL PROTECTED]> wrote:
>> Is it possible to get sequence support in RDBO? I know that
>> sequences are
>> supported for primary key generation, but I have a few cases where
>> they are
>> used for non-keyed columns
>
> What would this support look like? How would the sequence be
> specified, and how would it behave on insert, update, etc.?
>
>> But since next_value_in_sequence is not documented, I am worrying
>> that it's
>> interface may change or disappear.
>
> It almost certainly won't disappear and may become part of the public
> API eventually.
>
> -John
I'll second wanting support too :)
On Mar 20, 2007, at 1:11 PM, Derek Watson wrote:
> I suppose my use of serial/sequence columns is too specific to
> bother adding to the API, but basically
>
> some_seq_column => { type => 'serial', not_null => 1, sequence =>
> 'some_seq' },
That makes perfect sense to me. although that looks like what is in
there for oracle already
I'd actually like to see sequence classes
Rose::DB::Object::Metadata::Sequence
Which lets us map sequences to rose objects , and vice versa
I'd like to be able to call
my $seq= MyApp::Rose::DB::Object::Sequence1->new();
my $curval= $seq->curval;
my $nextval= $seq->nextval;
my $lastval = $seq->lastval;
getting that to work with all dbs might be a pain though.
I'll chime in with the Postgres compatibility -- if anyone wants this
support too, please comment on MySQL , SQLite, Oracle, etc
Postgres:
Create Sequence
http://www.postgresql.org/docs/8.2/interactive/sql-createsequence.html
Compatibility
CREATE SEQUENCE conforms to the SQL standard, with the
following
exceptions:
The standard's AS expression is not
supported.
Obtaining the next value is done using the nextval()
function
instead of the standard's NEXT VALUE FOR expression.
The OWNED BY clause is a PostgreSQL extension.
Alter Sequence
http://www.postgresql.org/docs/8.2/interactive/sql-altersequence.html
Compatibility
ALTER SEQUENCE conforms to the SQL standard, except for the
OWNED
BY and SET SCHEMA clauses, which are PostgreSQL extensions.
Drop Sequence
http://www.postgresql.org/docs/8.2/interactive/sql-dropsequence.html
Compatibility
DROP SEQUENCE conforms to the SQL standard, except that the
standard only allows one sequence to be dropped per command, and
apart from the IF EXISTS option, which is a PostgreSQL extension.
Sequence Manipulation Functions
http://www.postgresql.org/docs/8.2/interactive/functions-sequence.html
currval(regclass) bigint Return value most recently
obtained with
nextval for specified sequence
nextval(regclass) bigint Advance sequence and return new
value
setval(regclass, bigint) bigint Set sequence's current value
setval(regclass, bigint, boolean) bigintSet sequence's
current
value and is_called flag
lastval - Return the value most recently returned by nextval in
the
current session. This function is identical to currval, except that
instead of taking the sequence name as an argument it fetches the
value of the last sequence that nextval was used on in the current
session. It is an error to call lastval if nextval has not yet been
called in the current session.
Important: To avoid blocking of concurrent transactions that
obtain
numbers from the same sequence, a nextval operation is never rolled
back; that is, once a value has been fetched it is considered used,
even if the transaction that did the nextval later aborts. This means
that aborted transactions may leave unused "holes" in the sequence of
assigned values. setval operations are never rolled back, either.
// Jonathan Vanasco
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Re: [RDBO] Sequence Support
What would this support look like? How would the sequence be
specified, and how would it behave on insert, update, etc.?
I suppose my use of serial/sequence columns is too specific to bother adding
to the API, but basically
some_seq_column => { type => 'serial', not_null => 1, sequence => 'some_seq'
},
would use nextval('some_seq') on save if that column is missing. Similar to
the primary key generation that happens already.
But since next_value_in_sequence is not documented, I am worrying that
it's
> interface may change or disappear.
It almost certainly won't disappear and may become part of the public
API eventually.
Fantastic-- that's really all I need. Thanks for all the great work.
Derek
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Re: [RDBO] Sequence Support
On 3/20/07, Derek Watson <[EMAIL PROTECTED]> wrote: > Is it possible to get sequence support in RDBO? I know that sequences are > supported for primary key generation, but I have a few cases where they are > used for non-keyed columns What would this support look like? How would the sequence be specified, and how would it behave on insert, update, etc.? > But since next_value_in_sequence is not documented, I am worrying that it's > interface may change or disappear. It almost certainly won't disappear and may become part of the public API eventually. -John - Take Surveys. Earn Cash. Influence the Future of IT Join SourceForge.net's Techsay panel and you'll get the chance to share your opinions on IT & business topics through brief surveys-and earn cash http://www.techsay.com/default.php?page=join.php&p=sourceforge&CID=DEVDEV ___ Rose-db-object mailing list Rose-db-object@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/rose-db-object
