Re: [HACKERS] warning missing
Gaetano Mendola wrote: Tom Lane wrote: Gaetano Mendola [EMAIL PROTECTED] writes: I think a warning is missing if I create a table without OIDS that inherits from a table with oids: don't you think a warning shall to be raised here ? Nope ... this is not different from the behavior for merging duplicate column definitions. You get an OID column if the child table definition *or* any parent table requests OIDs. Mmm, you are not convincing me, don't we break the principle of minor surprise? I mean if you duplicate a column name that column is present on the inherited table, but if I say: I don't want the column OID and I found it, this then surprise me. Peter, what do you think about it ? Regards Gaetano Mendola ---(end of broadcast)--- TIP 5: Have you checked our extensive FAQ? http://www.postgresql.org/docs/faqs/FAQ.html
Re: [HACKERS] warning missing
Gaetano, I've been using C++ for 15 years and Java for 7. I like them both. Every language has its pros and cons. C++ can be extremely powerful in the hands of someone who knows how to use it. I actually wrote the first version of Pl/Java in C++. However, I got strong advice to rewrite it using plain C (which I did) to get maximum acceptance. Kind regards, Thomas Hallgren ---(end of broadcast)--- TIP 7: don't forget to increase your free space map settings
Re: [HACKERS] warning missing
Thomas Hallgren wrote: Greg, You don't like Java/C#. I do. What appear here is that you hate C++. I'm a C++ developer since long time now, and I can not use JAVA and or C# just for a couple of reason: 1) Java was supposed to be platform compatible: in thereality is not really true. 2) I can not use the RAII Idiom, or at least without be a joggler 3) I miss the const modifier for methods, and I really can not be sure of what happen to my objects when are used around. Do you want now speak about the missing template feature? Don't say template are the same of Generics. Regards Gaetano Mendola ---(end of broadcast)--- TIP 8: explain analyze is your friend
Re: [HACKERS] warning missing
Hello, You all are behind... Python is king. Sincerely, Joshua D. Drake Gaetano Mendola wrote: Thomas Hallgren wrote: Greg, You don't like Java/C#. I do. What appear here is that you hate C++. I'm a C++ developer since long time now, and I can not use JAVA and or C# just for a couple of reason: 1) Java was supposed to be platform compatible: in thereality is not really true. 2) I can not use the RAII Idiom, or at least without be a joggler 3) I miss the const modifier for methods, and I really can not be sure of what happen to my objects when are used around. Do you want now speak about the missing template feature? Don't say template are the same of Generics. Regards Gaetano Mendola ---(end of broadcast)--- TIP 8: explain analyze is your friend -- Command Prompt, Inc., home of Mammoth PostgreSQL - S/ODBC and S/JDBC Postgresql support, programming shared hosting and dedicated hosting. +1-503-667-4564 - [EMAIL PROTECTED] - http://www.commandprompt.com Mammoth PostgreSQL Replicator. Integrated Replication for PostgreSQL begin:vcard fn:Joshua D. Drake n:Drake;Joshua D. org:Command Prompt, Inc. adr:;;PO Box 215;Cascade Locks;Oregon;97014;USA email;internet:[EMAIL PROTECTED] title:Consultant tel;work:503-667-4564 tel;fax:503-210-0034 note:Command Prompt, Inc. is the largest and oldest US based commercial PostgreSQL support provider. We provide the only commercially viable integrated PostgreSQL replication solution, but also custom programming, and support. We authored the book Practical PostgreSQL, the procedural language plPHP, and adding trigger capability to plPerl. x-mozilla-html:FALSE url:http://www.commandprompt.com/ version:2.1 end:vcard ---(end of broadcast)--- TIP 1: subscribe and unsubscribe commands go to [EMAIL PROTECTED]
Re: [HACKERS] warning missing
Joshua D. Drake wrote: Hello, You all are behind... Python is king. Just to throw more fuel on the fire. Relvar inheritance is, according to Chris Date, one of the two Great Blunders in database engineering over the past twenty years. Multiple Domain Inheritance: Yes Relation Variable Inheritance: No I think it'd be a fair statement that Date Darwen would have the relvar inheritance ripped out of PostgreSQL as an experiment gone bad... Mike Mascari P.S.: D is the language of the future: http://www.digitalmars.com/d Ha! ---(end of broadcast)--- TIP 2: you can get off all lists at once with the unregister command (send unregister YourEmailAddressHere to [EMAIL PROTECTED])
Re: [HACKERS] warning missing
Thomas Hallgren [EMAIL PROTECTED] writes: From an OO semantics point of view, I still regard Java and C# much more elaborate than both C++ and Common Lisp. The latter lacks interfaces and different levels of protection. It doesn't lack interfaces. It has actual multiple inheritance. Which is what interfaces are there to substitute for. -- greg ---(end of broadcast)--- TIP 8: explain analyze is your friend
Re: [HACKERS] warning missing
Greg Stark [EMAIL PROTECTED] wrote in message news:[EMAIL PROTECTED] Thomas Hallgren [EMAIL PROTECTED] writes: From an OO semantics point of view, I still regard Java and C# much more elaborate than both C++ and Common Lisp. The latter lacks interfaces and different levels of protection. It doesn't lack interfaces. It has actual multiple inheritance. Which is what interfaces are there to substitute for. Yes, it does lack interfaces and no, interfaces are definitely *not* a substitute for multiple inheritance. An interface is a contract and behind that contract you may have several different implementations. JDBC is a good example. PostgreSQL has a JDBC driver. So do most other database vendors. The thing they have in common is that they implement a set of interfaces that together constitutes a contract stipulated by a version of JDBC. I think we are drifting far apart from the actual subject now. Wether or not Common Lisp has interfaces seems somewhat irrelevant to the original question. Kind regards, Thomas Hallgren ---(end of broadcast)--- TIP 2: you can get off all lists at once with the unregister command (send unregister YourEmailAddressHere to [EMAIL PROTECTED])
Re: [HACKERS] warning missing
Greg, You don't like Java/C#. I do. There's not much point arguing about it. You feel that abstract classes are equivalent to interfaces provided you have multiple inheritance, I don't since I'm in favor of a totally clean interface/implementation separation. Now you bring in the Java security model. We could of course discuss that and I could argue that MI was rejected for other reasons then the one you mention. But I don't think that's going to lead anywhere. If you feel that C++ and/or Common Lisp is a better OO language then Java and C#, then for you it certanly is. For me it's not. Let's just respect eachothers standpoint and end the discussion here. Kind regards, Thomas Hallgren ---(end of broadcast)--- TIP 4: Don't 'kill -9' the postmaster
Re: [HACKERS] warning missing
Gaetano Mendola [EMAIL PROTECTED] writes: Tom Lane wrote: Gaetano Mendola [EMAIL PROTECTED] writes: I think a warning is missing if I create a table without OIDS that inherits from a table with oids: don't you think a warning shall to be raised here ? Nope ... this is not different from the behavior for merging duplicate column definitions. You get an OID column if the child table definition *or* any parent table requests OIDs. Mmm, you are not convincing me, don't we break the principle of minor surprise? I mean if you duplicate a column name that column is present on the inherited table, but if I say: I don't want the column OID and I found it, this then surprise me. Speaking in generic OO terms, using inheritance, you cannot remove attributes that are present in the generalisation. If B inherits A, an instance of B is per definition also an instance of A. Thus, you must alwasy be able to cast a B into an A. In short, If you don't want the OID, you cannot inherit a something that has an OID. Having said that, I think a warning is motivated. The warning should state that attributes (columns) present in the generalisation (the parent table) cannot be hidden. Kind regards, Thomas Hallgren ---(end of broadcast)--- TIP 1: subscribe and unsubscribe commands go to [EMAIL PROTECTED]
Re: [HACKERS] warning missing
Gaetano Mendola wrote:
Thomas Hallgren wrote:
Speaking in generic OO terms, using inheritance, you cannot remove
attributes that are present in the generalisation. If B inherits A, an
instance of B is per definition also an instance of A. Thus, you must
alwasy
be able to cast a B into an A. In short, If you don't want the OID, you
cannot inherit a something that has an OID.
This is not completely true:
struct B
{
void foo();
};
class D : public B
{
private:
void foo();
public:
void bar();
};
as you can see a D is a B but the publich foo() doesn't
appartaint to D, at least an user of D could not use foo()
C++ is not exactly the model for OO semantics. It's a fairly wierd
addition to C resulting in a hybrid language where quite a few
constructs violates sane OO. Try to use a similar construct in a more
elaborate OO-language (like Java, C#, etc.) and you will get an error like:
foo() in D cannot override foo() in B; attempting to assign weaker
access privileges; was public
which makes a lot more sense.
Kind regards,
Thomas Hallgren
PS. This discussion doesn't really belong here. I'd be happy to continue
it off the list though.
---(end of broadcast)---
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Re: [HACKERS] warning missing
Thomas Hallgren [EMAIL PROTECTED] writes: Try to use a similar construct in a more elaborate OO-language (like Java, C#, etc.) and you will get an error like: Just as a point of reference, Java and C# are not more elaborate object systems. For Java at least being *less* elaborate was an explicit design goal. The designers thought C++ had too many features and gave programmers too much rope to hang themselves. They thought by removing major OO features that confuse people the resulting language would be 90% as functional with 10% of the problems. If you want a *more* elaborate OO language than C++ you would have to go to, say, Common Lisp. But I doubt it would support your argument. Common Lisp goes pretty far out of its way to make sure you can do whatever you dream of under the sun. In any case it would make a weak argument given the slim portion of programmers that know Common Lisp. -- greg ---(end of broadcast)--- TIP 1: subscribe and unsubscribe commands go to [EMAIL PROTECTED]
Re: [HACKERS] warning missing
Greg Stark [EMAIL PROTECTED] wrote in message news:[EMAIL PROTECTED] Thomas Hallgren [EMAIL PROTECTED] writes: Try to use a similar construct in a more elaborate OO-language (like Java, C#, etc.) and you will get an error like: Just as a point of reference, Java and C# are not more elaborate object systems. For Java at least being *less* elaborate was an explicit design goal. I mean more elaborate from a n OO semantics standpoint. I.e. it enforces OO much more, provides better data hiding, the ability to use interfaces (and thereby enforce interface/implementation separation), package protection, etc. etc. To elaborate something doesn't necessarily mean adding more kludges to a language. The designers thought C++ had too many features and gave programmers too much rope to hang themselves. They thought by removing major OO features that confuse people the resulting language would be 90% as functional with 10% of the problems. If you want a *more* elaborate OO language than C++ you would have to go to, say, Common Lisp. But I doubt it would support your argument. I'm not an expert on Common Lisp but I think it would. At least if you'd use CLOS and defclass. There's no way to hide readers/writers/accessors that you inherit. From an OO semantics point of view, I still regard Java and C# much more elaborate than both C++ and Common Lisp. The latter lacks interfaces and different levels of protection. Kind regards, Thomas Hallgren ---(end of broadcast)--- TIP 3: if posting/reading through Usenet, please send an appropriate subscribe-nomail command to [EMAIL PROTECTED] so that your message can get through to the mailing list cleanly
Re: [HACKERS] warning missing
Gaetano Mendola [EMAIL PROTECTED] writes: I think a warning is missing if I create a table without OIDS that inherits from a table with oids: don't you think a warning shall to be raised here ? Nope ... this is not different from the behavior for merging duplicate column definitions. You get an OID column if the child table definition *or* any parent table requests OIDs. regards, tom lane ---(end of broadcast)--- TIP 5: Have you checked our extensive FAQ? http://www.postgresql.org/docs/faqs/FAQ.html
Re: [HACKERS] warning missing
Tom Lane wrote: Gaetano Mendola [EMAIL PROTECTED] writes: I think a warning is missing if I create a table without OIDS that inherits from a table with oids: don't you think a warning shall to be raised here ? Nope ... this is not different from the behavior for merging duplicate column definitions. You get an OID column if the child table definition *or* any parent table requests OIDs. Mmm, you are not convincing me, don't we break the principle of minor surprise? I mean if you duplicate a column name that column is present on the inherited table, but if I say: I don't want the column OID and I found it, this then surprise me. Regards Gaetano Mendola ---(end of broadcast)--- TIP 9: the planner will ignore your desire to choose an index scan if your joining column's datatypes do not match
