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* No documentation exists about ecpg ORACLE comptaible mode
@ 2022-06-07 08:28 [email protected] <[email protected]>
2022-07-10 01:15 ` Re: No documentation exists about ecpg ORACLE comptaible mode Bruce Momjian <[email protected]>
0 siblings, 1 reply; 6+ messages in thread
From: [email protected] @ 2022-06-07 08:28 UTC (permalink / raw)
To: '[email protected]' <[email protected]>; +Cc: '[email protected]' <[email protected]>
Hi.
(CCing Michael Meskes)
One of my customers asked me about what oracle compatibility mode in ecpg means,
and I noticed current documentation does not explain ecpg ORACLE compatible mode (ecpg -C ORACLE) in detail.
I myself learned the feature of "-C ORACLE" from regression test (src/interfaces/ecpg/test/compat_oracle) and source code.
Is lacking documentation intentional or do commit 3b7ab4380 and 3b9b7516f just forget adding the explanation?
As for as I know, "ecpg -C ORACLE" is written briefly in ecpg command reference and PostgreSQL 11 release note,
but they are not enougn information for users to understand feature of "ecpg -C ORACLE".
https://www.postgresql.org/docs/current/app-ecpg.html
-------------------------------
-C mode
Set a compatibility mode. mode can be INFORMIX, INFORMIX_SE, or ORACLE.
-------------------------------
https://www.postgresql.org/docs/11/release-11.html#id-1.11.6.21.5.9
-------------------------------
Add an ecpg mode to enable Oracle Pro*C-style handling of char arrays.
This mode is enabled with -C.
-------------------------------
On the other hand, informix compatible mode is written in detail.
https://www.postgresql.org/docs/current/ecpg-informix-compat.html
Best regards,
Takeshi Ideriha
^ permalink raw reply [nested|flat] 6+ messages in thread
* Re: No documentation exists about ecpg ORACLE comptaible mode
2022-06-07 08:28 No documentation exists about ecpg ORACLE comptaible mode [email protected] <[email protected]>
@ 2022-07-10 01:15 ` Bruce Momjian <[email protected]>
2022-07-12 08:20 ` Re: No documentation exists about ecpg ORACLE comptaible mode Michael Meskes <[email protected]>
2022-07-14 02:41 ` RE: No documentation exists about ecpg ORACLE comptaible mode [email protected] <[email protected]>
0 siblings, 2 replies; 6+ messages in thread
From: Bruce Momjian @ 2022-07-10 01:15 UTC (permalink / raw)
To: [email protected] <[email protected]>; +Cc: '[email protected]' <[email protected]>; '[email protected]' <[email protected]>
On Tue, Jun 7, 2022 at 08:28:55AM +0000, [email protected] wrote:
> Hi.
> (CCing Michael Meskes)
>
> One of my customers asked me about what oracle compatibility mode in ecpg means,
> and I noticed current documentation does not explain ecpg ORACLE compatible mode (ecpg -C ORACLE) in detail.
> I myself learned the feature of "-C ORACLE" from regression test (src/interfaces/ecpg/test/compat_oracle) and source code.
>
> Is lacking documentation intentional or do commit 3b7ab4380 and 3b9b7516f just forget adding the explanation?
>
> As for as I know, "ecpg -C ORACLE" is written briefly in ecpg command reference and PostgreSQL 11 release note,
> but they are not enougn information for users to understand feature of "ecpg -C ORACLE".
>
> https://www.postgresql.org/docs/current/app-ecpg.html
>
> -------------------------------
> -C mode
> Set a compatibility mode. mode can be INFORMIX, INFORMIX_SE, or ORACLE.
> -------------------------------
>
> https://www.postgresql.org/docs/11/release-11.html#id-1.11.6.21.5.9
> -------------------------------
> Add an ecpg mode to enable Oracle Pro*C-style handling of char arrays.
>
> This mode is enabled with -C.
> -------------------------------
>
> On the other hand, informix compatible mode is written in detail.
> https://www.postgresql.org/docs/current/ecpg-informix-compat.html
This is a very good point. I have studied the issue and created the
attached patch to document Oracle-compatibility mode.
--
Bruce Momjian <[email protected]> https://momjian.us
EDB https://enterprisedb.com
Indecision is a decision. Inaction is an action. Mark Batterson
Attachments:
[text/x-diff] ecpg.diff (1.6K, 2-ecpg.diff)
download | inline diff:
diff --git a/doc/src/sgml/ecpg.sgml b/doc/src/sgml/ecpg.sgml
index 7f8b4dd5c0..999b7ca0ae 100644
--- a/doc/src/sgml/ecpg.sgml
+++ b/doc/src/sgml/ecpg.sgml
@@ -1890,7 +1890,8 @@ EXEC SQL SELECT b INTO :val :val_ind FROM test1;
</programlisting>
The indicator variable <varname>val_ind</varname> will be zero if
the value was not null, and it will be negative if the value was
- null.
+ null. (See <xref linkend="ecpg-oracle-compat"/> to enable
+ Oracle-specific behavior.)
</para>
<para>
@@ -9799,6 +9800,42 @@ risnull(CINTTYPE, (char *) &i);
</sect2>
</sect1>
+ <sect1 id="ecpg-oracle-compat">
+ <title><productname>Oracle</productname> Compatibility Mode</title>
+ <para>
+ <command>ecpg</command> can be run in a so-called <firstterm>Oracle
+ compatibility mode</firstterm>. If this mode is active, it tries to
+ behave as if it were Oracle <productname>Pro*C</productname>.
+ </para>
+
+ <para>
+ Specifically, this mode changes <command>ecpg</command> in three ways:
+
+ <itemizedlist>
+ <listitem>
+ <para>
+ Pad character arrays receiving character string types with
+ trailing spaces to the specified length
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ Zero byte terminate these character arrays, and set the indicator
+ variable if truncation occurs
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ Set the null indicator to <literal>-1</literal> when character
+ arrays receive empty character string types
+ </para>
+ </listitem>
+ </itemizedlist>
+ </para>
+ </sect1>
+
<sect1 id="ecpg-develop">
<title>Internals</title>
^ permalink raw reply [nested|flat] 6+ messages in thread
* Re: No documentation exists about ecpg ORACLE comptaible mode
2022-06-07 08:28 No documentation exists about ecpg ORACLE comptaible mode [email protected] <[email protected]>
2022-07-10 01:15 ` Re: No documentation exists about ecpg ORACLE comptaible mode Bruce Momjian <[email protected]>
@ 2022-07-12 08:20 ` Michael Meskes <[email protected]>
2022-07-12 18:46 ` Re: No documentation exists about ecpg ORACLE comptaible mode Bruce Momjian <[email protected]>
1 sibling, 1 reply; 6+ messages in thread
From: Michael Meskes @ 2022-07-12 08:20 UTC (permalink / raw)
To: Bruce Momjian <[email protected]>; +Cc: [email protected] <[email protected]>; '[email protected]' <[email protected]>; '[email protected]' <[email protected]>
On Sat, Jul 09, 2022 at 09:15:52PM -0400, Bruce Momjian wrote:
> This is a very good point. I have studied the issue and created the
> attached patch to document Oracle-compatibility mode.
> ...
Looks good to me. Thanks a bunch Bruce.
I wonder if we should also mention somewhere that some other Oracle
compatibility features are enable in all modes, like a slightly different
CONNECT syntax.
Michael
--
Michael Meskes
Michael at Fam-Meskes dot De
Michael at Meskes dot (De|Com|Net|Org)
Meskes at (Debian|Postgresql) dot Org
^ permalink raw reply [nested|flat] 6+ messages in thread
* Re: No documentation exists about ecpg ORACLE comptaible mode
2022-06-07 08:28 No documentation exists about ecpg ORACLE comptaible mode [email protected] <[email protected]>
2022-07-10 01:15 ` Re: No documentation exists about ecpg ORACLE comptaible mode Bruce Momjian <[email protected]>
2022-07-12 08:20 ` Re: No documentation exists about ecpg ORACLE comptaible mode Michael Meskes <[email protected]>
@ 2022-07-12 18:46 ` Bruce Momjian <[email protected]>
0 siblings, 0 replies; 6+ messages in thread
From: Bruce Momjian @ 2022-07-12 18:46 UTC (permalink / raw)
To: Michael Meskes <[email protected]>; +Cc: [email protected] <[email protected]>; '[email protected]' <[email protected]>
On Tue, Jul 12, 2022 at 10:20:08AM +0200, Michael Meskes wrote:
> On Sat, Jul 09, 2022 at 09:15:52PM -0400, Bruce Momjian wrote:
> > This is a very good point. I have studied the issue and created the
> > attached patch to document Oracle-compatibility mode.
> > ...
>
> Looks good to me. Thanks a bunch Bruce.
Great, thanks.
> I wonder if we should also mention somewhere that some other Oracle
> compatibility features are enable in all modes, like a slightly different
> CONNECT syntax.
Good question. We support syntax from other databases, only sometimes
with documentation. I think the rules we use are that we document
compatibility-only behavior when it is useful and obviously if it is
turned in by an option.
In contrast, look at this from backend/parser/gram.y:
/* INOUT is SQL99 standard, IN OUT is for Oracle compatibility */
arg_class: IN_P { $$ = FUNC_PARAM_IN; }
| OUT_P { $$ = FUNC_PARAM_OUT; }
| INOUT { $$ = FUNC_PARAM_INOUT; }
| IN_P OUT_P { $$ = FUNC_PARAM_INOUT; }
| VARIADIC { $$ = FUNC_PARAM_VARIADIC; }
We don't document "IN OUT" anywhere, we just support it silently for
Oracle compatibility, and I am guessing your ecpg connection syntax is
similar. I think this is done so we don't confuse people with syntax
that has not value unless they are coming from another database.
Therefore, I don't think we should document it, but I would be
interested to hear if anyone disagrees.
--
Bruce Momjian <[email protected]> https://momjian.us
EDB https://enterprisedb.com
Indecision is a decision. Inaction is an action. Mark Batterson
^ permalink raw reply [nested|flat] 6+ messages in thread
* RE: No documentation exists about ecpg ORACLE comptaible mode
2022-06-07 08:28 No documentation exists about ecpg ORACLE comptaible mode [email protected] <[email protected]>
2022-07-10 01:15 ` Re: No documentation exists about ecpg ORACLE comptaible mode Bruce Momjian <[email protected]>
@ 2022-07-14 02:41 ` [email protected] <[email protected]>
2022-07-14 20:20 ` Re: No documentation exists about ecpg ORACLE comptaible mode 'Bruce Momjian' <[email protected]>
1 sibling, 1 reply; 6+ messages in thread
From: [email protected] @ 2022-07-14 02:41 UTC (permalink / raw)
To: 'Bruce Momjian' <[email protected]>; +Cc: '[email protected]' <[email protected]>; '[email protected]' <[email protected]>
Bruce Momjian <[email protected]> wrote:
> This is a very good point. I have studied the issue and created the attached patch to document Oracle-compatibility mode.
Hi Bruce, thank you for writing the document.
I checked it and I'm very glad!
Regards,
Takeshi Ideriha
^ permalink raw reply [nested|flat] 6+ messages in thread
* Re: No documentation exists about ecpg ORACLE comptaible mode
2022-06-07 08:28 No documentation exists about ecpg ORACLE comptaible mode [email protected] <[email protected]>
2022-07-10 01:15 ` Re: No documentation exists about ecpg ORACLE comptaible mode Bruce Momjian <[email protected]>
2022-07-14 02:41 ` RE: No documentation exists about ecpg ORACLE comptaible mode [email protected] <[email protected]>
@ 2022-07-14 20:20 ` 'Bruce Momjian' <[email protected]>
0 siblings, 0 replies; 6+ messages in thread
From: 'Bruce Momjian' @ 2022-07-14 20:20 UTC (permalink / raw)
To: [email protected] <[email protected]>; +Cc: '[email protected]' <[email protected]>; '[email protected]' <[email protected]>
On Thu, Jul 14, 2022 at 02:41:45AM +0000, [email protected] wrote:
> Bruce Momjian <[email protected]> wrote:
>
> > This is a very good point. I have studied the issue and created the attached patch to document Oracle-compatibility mode.
>
> Hi Bruce, thank you for writing the document.
> I checked it and I'm very glad!
Patch applied to PG 11, where the feature was added, and later.
--
Bruce Momjian <[email protected]> https://momjian.us
EDB https://enterprisedb.com
Indecision is a decision. Inaction is an action. Mark Batterson
^ permalink raw reply [nested|flat] 6+ messages in thread
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2022-06-07 08:28 No documentation exists about ecpg ORACLE comptaible mode [email protected] <[email protected]>
2022-07-10 01:15 ` Bruce Momjian <[email protected]>
2022-07-12 08:20 ` Michael Meskes <[email protected]>
2022-07-12 18:46 ` Bruce Momjian <[email protected]>
2022-07-14 02:41 ` [email protected] <[email protected]>
2022-07-14 20:20 ` 'Bruce Momjian' <[email protected]>
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