Обсуждение: ANSI Standard

On Tue, Jun 24, 2008 at 7:33 AM, Pascal Tufenkji <ptufenkji@usj.edu.lb> wrote:

> How do I know if a function (or a certain sql syntax) in Postgres is a SQL
> ANSI Standard, hence it works on all databases such as MySQL, SQL Server,
> Oracle…


> I noticed that concat, decode, nvl, instr are functions that work for some
> databases and don't for others.
>
> I only want to use ANSI Standard functions that work everywhere.

Well the problem is that most database do not support that same full
set of ANSI features.  So if you design your schema with a wide range
of ansi features, certain ddl will probably not commit or at least
will be ignored on most databases.  We database brand has incorporated
a different set of features.

> How do I identify them?

This should get you started :
http://www.postgresql.org/docs/8.3/interactive/features.html

--
Regards,
Richard Broersma Jr.

Visit the Los Angles PostgreSQL Users Group (LAPUG)
http://pugs.postgresql.org/lapug

At 02:20 AM 6/25/2008, pgsql-sql-owner@postgresql.org wrote:
>Date: Tue, 24 Jun 2008 17:33:11 +0300
>From: "Pascal Tufenkji" <ptufenkji@usj.edu.lb>
>To: <pgsql-sql@postgresql.org>
>Subject: ANSI Standard
>Message-ID: <000601c8d607$3acda550$150fa8c0@interne.usj.edu.lb>
>
>Hi,
>
>
>
>How do I know if a function (or a certain sql syntax) in Postgres is a 
>SQL
>ANSI Standard, hence it works on all databases such as MySQL, SQL 
>Server,
>Oracle.

In general, I find that the Pg docs pretty clear state what is ANSI 
standard and what isn't within Pg. You can also view the ANSI-92 
standard here:

http://www.contrib.andrew.cmu.edu/~shadow/sql/sql1992.txt

In terms of making sure you're cross platform compatible, I'd say you 
have to designate a series of platforms (e.g. MySQL 5, Pg 8.3, Oracle 
X, MS SQL X, ext) which you will test against and explicitly support. 
You will find that no matter how tightly you attempt to build your 
platform against ANSI-92 (or any other std) if you do not regularly 
test against a set of platforms, your solution will converge on 
supporting only the platforms you do regular test against.

I hope that helps,

Steve

- Try SQL 2003 standards....92 is way old
- You'll find that even the big boys like Oracle, DB2 etc will diverge from SQL standards if they make more $$ thier way...let alone toys like MySQL and MS-SQL

Cheers
Medi