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Re: [pgsql-general 2011-1-21:] Are there any projects interested in object functionality? (+ rule bases)

From: Pavel Stehule <pavel(dot)stehule(at)gmail(dot)com>
To: Robert Haas <robertmhaas(at)gmail(dot)com>
Cc: Nick Rudnick <joerg(dot)rudnick(at)t-online(dot)de>, pgsql-hackers(at)postgresql(dot)org
Subject: Re: [pgsql-general 2011-1-21:] Are there any projects interested in object functionality? (+ rule bases)
Date: 2011-02-01 04:43:59
Message-ID: AANLkTikCJ+X5S5VWJV6NDgOzb1_oQB6PgjXWj9CvG71C@mail.gmail.com (view raw or flat)
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Lists: pgsql-hackers
Hello

it is part of ANSi SQL 2003

http://savage.net.au/SQL/sql-2003-2.bnf.html#method%20specification%20designator


2011/2/1 Pavel Stehule <pavel(dot)stehule(at)gmail(dot)com>:
> 2011/2/1 Robert Haas <robertmhaas(at)gmail(dot)com>:
>> On Mon, Jan 31, 2011 at 5:09 PM, Nick Rudnick <joerg(dot)rudnick(at)t-online(dot)de> wrote:
>>> Interesting... I remember that some years ago, I fiddled around with
>>> functions, operators etc. to allow a method like syntax -- but I ever was
>>> worried this approach would have serious weaknesses -- are there any
>>> principal hindrances to having methods, if no, can this be implemented in a
>>> straightforward way?
>>
>> It would help if you were a bit more specific.  Do you mean you want
>> to write something like foo.bar(baz) and have that mean call the bar
>> method of foo and pass it baz as an argument?
>>
>> If so, that'd certainly be possible to implement for purposes of a
>> college course, if you're so inclined - after all it's free software -
>> but we'd probably not make such a change to core PG, because right now
>> that would mean call the function bar in schema baz and pass it foo as
>> an argument.  We try not to break people's code to when adding
>> nonstandard features.
>>
>
> I has not a standard, so I am not sure what is in standard and what
> not. It was a popular theme about year 2000 and OOP was planed to
> SQL3. You can find a some presentation from this time. Oracle
> implemented these features.
>
> J. Melton: SQL:1999: Understanding Object-Relational and
> Other Advanced Features, Morgan Kaufmann, 2003.
>
>
> CREATE METHOD next_color (n INT)
> RETURNS INT
> FOR colored_part_t
> RETURN SELF.color_id + n
>
> SELECT partno, color_id, DEREF(oid).next_color(1) AS next
> FROM colored_parts
>
> some other databases implemented a dereferenced data (it's not only
> Oracle's subject)
>
> http://www.java2s.com/Code/Oracle/Object-Oriented-Database/DEREFDereferencetheRowAddresses.htm
>
> Probably DB2 implements this functionality too. See doc for CREATE
> TYPE statement, REF USING, NOT FINAL, method specification
>
>  CREATE TYPE  type-name
>       ...
>     METHOD attribute-name()
>       RETURNS attribute-type
>
> these features are very nice - but is not well documented and probably not used.
>
> Pavel
>
>> --
>> Robert Haas
>> EnterpriseDB: http://www.enterprisedb.com
>> The Enterprise PostgreSQL Company
>>
>

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