Re: [HACKERS] conditional dropping of columns/constraints

2009-07-19 Thread Andrew Dunstan 



Bernd Helmle wrote:


Here is a slightly updated version of the patch. I did some (very 
minor) editing on the wording in the docs and cleaned a merge conflict 
in tablecmds.c. I saw no code issues so far, make check passes without 
errors. Maybe someone with more bison skills can comment on the 
duplicated parser stuff, but it seems consistent with the rest of the 
code.


The duplicated stuff in the grammar is pretty much what had to be done 
for other DROP IF EXISTS items to avoid shift/reduce conflicts, so it's 
quite kosher.


patch committed.

Thanks.

andrew

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Re: [HACKERS] conditional dropping of columns/constraints

2009-07-09 Thread Bernd Helmle 
--On Donnerstag, Mai 07, 2009 12:57:56 +0200 Andres Freund 
and...@anarazel.de wrote:



Ok, fixed that place (stupid me, I had seen that it is used there and
forgot about it) and found no other places.

Thanks,

Andres


Here is a slightly updated version of the patch. I did some (very minor) 
editing on the wording in the docs and cleaned a merge conflict in 
tablecmds.c. I saw no code issues so far, make check passes without errors. 
Maybe someone with more bison skills can comment on the duplicated parser 
stuff, but it seems consistent with the rest of the code.


--
 Thanks

   Bernd
diff --git a/doc/src/sgml/ref/alter_table.sgml b/doc/src/sgml/ref/alter_table.sgml
index fe3f388..f065e78 100644
*** a/doc/src/sgml/ref/alter_table.sgml
--- b/doc/src/sgml/ref/alter_table.sgml
*** ALTER TABLE replaceable class=PARAMETE
*** 33,39 
  where replaceable class=PARAMETERaction/replaceable is one of:
  
  ADD [ COLUMN ] replaceable class=PARAMETERcolumn/replaceable replaceable class=PARAMETERtype/replaceable [ replaceable class=PARAMETERcolumn_constraint/replaceable [ ... ] ]
! DROP [ COLUMN ] replaceable class=PARAMETERcolumn/replaceable [ RESTRICT | CASCADE ]
  ALTER [ COLUMN ] replaceable class=PARAMETERcolumn/replaceable [ SET DATA ] TYPE replaceable class=PARAMETERtype/replaceable [ USING replaceable class=PARAMETERexpression/replaceable ]
  ALTER [ COLUMN ] replaceable class=PARAMETERcolumn/replaceable SET DEFAULT replaceable class=PARAMETERexpression/replaceable
  ALTER [ COLUMN ] replaceable class=PARAMETERcolumn/replaceable DROP DEFAULT
--- 33,39 
  where replaceable class=PARAMETERaction/replaceable is one of:
  
  ADD [ COLUMN ] replaceable class=PARAMETERcolumn/replaceable replaceable class=PARAMETERtype/replaceable [ replaceable class=PARAMETERcolumn_constraint/replaceable [ ... ] ]
! DROP [ COLUMN ] [ IF EXISTS ] replaceable class=PARAMETERcolumn/replaceable [ RESTRICT | CASCADE ]
  ALTER [ COLUMN ] replaceable class=PARAMETERcolumn/replaceable [ SET DATA ] TYPE replaceable class=PARAMETERtype/replaceable [ USING replaceable class=PARAMETERexpression/replaceable ]
  ALTER [ COLUMN ] replaceable class=PARAMETERcolumn/replaceable SET DEFAULT replaceable class=PARAMETERexpression/replaceable
  ALTER [ COLUMN ] replaceable class=PARAMETERcolumn/replaceable DROP DEFAULT
*** where replaceable class=PARAMETERact
*** 41,47 
  ALTER [ COLUMN ] replaceable class=PARAMETERcolumn/replaceable SET STATISTICS replaceable class=PARAMETERinteger/replaceable
  ALTER [ COLUMN ] replaceable class=PARAMETERcolumn/replaceable SET STORAGE { PLAIN | EXTERNAL | EXTENDED | MAIN }
  ADD replaceable class=PARAMETERtable_constraint/replaceable
! DROP CONSTRAINT replaceable class=PARAMETERconstraint_name/replaceable [ RESTRICT | CASCADE ]
  DISABLE TRIGGER [ replaceable class=PARAMETERtrigger_name/replaceable | ALL | USER ]
  ENABLE TRIGGER [ replaceable class=PARAMETERtrigger_name/replaceable | ALL | USER ]
  ENABLE REPLICA TRIGGER replaceable class=PARAMETERtrigger_name/replaceable
--- 41,47 
  ALTER [ COLUMN ] replaceable class=PARAMETERcolumn/replaceable SET STATISTICS replaceable class=PARAMETERinteger/replaceable
  ALTER [ COLUMN ] replaceable class=PARAMETERcolumn/replaceable SET STORAGE { PLAIN | EXTERNAL | EXTENDED | MAIN }
  ADD replaceable class=PARAMETERtable_constraint/replaceable
! DROP CONSTRAINT [ IF EXISTS ]  replaceable class=PARAMETERconstraint_name/replaceable [ RESTRICT | CASCADE ]
  DISABLE TRIGGER [ replaceable class=PARAMETERtrigger_name/replaceable | ALL | USER ]
  ENABLE TRIGGER [ replaceable class=PARAMETERtrigger_name/replaceable | ALL | USER ]
  ENABLE REPLICA TRIGGER replaceable class=PARAMETERtrigger_name/replaceable
*** where replaceable class=PARAMETERact
*** 82,88 
 /varlistentry
  
 varlistentry
! termliteralDROP COLUMN/literal/term
  listitem
   para
This form drops a column from a table.  Indexes and
--- 82,88 
 /varlistentry
  
 varlistentry
! termliteralDROP COLUMN [ IF EXISTS ]/literal/term
  listitem
   para
This form drops a column from a table.  Indexes and
*** where replaceable class=PARAMETERact
*** 90,95 
--- 90,98 
dropped as well.  You will need to say literalCASCADE/ if
anything outside the table depends on the column, for example,
foreign key references or views.
+   If literalIF EXISTS/literal is specified and the column 
+   does not exist, no error is thrown. In this case a notice 
+   is issued instead.
   /para
  /listitem
 /varlistentry
*** where replaceable class=PARAMETERact
*** 192,201 
 /varlistentry
  
 varlistentry
! termliteralDROP CONSTRAINT/literal/term
  listitem
   para
This form drops the specified constraint on a table.

Re: [HACKERS] conditional dropping of columns/constraints

2009-05-07 Thread Andres Freund 

Hi Tom, hi all,

On 05/06/2009 11:43 PM, Tom Lane wrote:

Andres Freundand...@anarazel.de  writes:

As this is my first patch to PG I am happy with most sort of feedback.

Please add your patch to the commit-fest queue here:
http://wiki.postgresql.org/wiki/CommitFestInProgress

Will do so, after this email has arrived.


Since we are still busy with 8.4 beta, it's unlikely that anyone will
take a close look until the next commit fest begins.  FWIW, I took a
very fast look through the patch and thought it was at least touching
the right places, except I think you missed equalfuncs.c.  (It'd be a
good idea to grep for all uses of AlterTableCmd struct to see if you
missed anything else.)  I don't have time now to look closer or do any
testing.
Ok, fixed that place (stupid me, I had seen that it is used there and 
forgot about it) and found no other places.


Thanks,

Andres
From adca6b0f0409c3ea95c5e93ab5e1d8f3f3edf802 Mon Sep 17 00:00:00 2001
From: Andres Freund and...@anarazel.de
Date: Thu, 7 May 2009 00:53:45 +0200
Subject: [PATCH] Feature: DROP (COLUMN|CONSTRAINT) IF EXISTS

---
 doc/src/sgml/ref/alter_table.sgml |   14 --
 src/backend/commands/tablecmds.c  |   74 -
 src/backend/nodes/copyfuncs.c |1 +
 src/backend/nodes/equalfuncs.c|1 +
 src/backend/parser/gram.y |   22 +
 src/include/nodes/parsenodes.h|1 +
 src/test/regress/expected/alter_table.out |   10 
 src/test/regress/sql/alter_table.sql  |9 
 8 files changed, 106 insertions(+), 26 deletions(-)

diff --git a/doc/src/sgml/ref/alter_table.sgml b/doc/src/sgml/ref/alter_table.sgml
index fe3f388..9678236 100644
*** a/doc/src/sgml/ref/alter_table.sgml
--- b/doc/src/sgml/ref/alter_table.sgml
*** ALTER TABLE replaceable class=PARAMETE
*** 33,39 
  where replaceable class=PARAMETERaction/replaceable is one of:
  
  ADD [ COLUMN ] replaceable class=PARAMETERcolumn/replaceable replaceable class=PARAMETERtype/replaceable [ replaceable class=PARAMETERcolumn_constraint/replaceable [ ... ] ]
! DROP [ COLUMN ] replaceable class=PARAMETERcolumn/replaceable [ RESTRICT | CASCADE ]
  ALTER [ COLUMN ] replaceable class=PARAMETERcolumn/replaceable [ SET DATA ] TYPE replaceable class=PARAMETERtype/replaceable [ USING replaceable class=PARAMETERexpression/replaceable ]
  ALTER [ COLUMN ] replaceable class=PARAMETERcolumn/replaceable SET DEFAULT replaceable class=PARAMETERexpression/replaceable
  ALTER [ COLUMN ] replaceable class=PARAMETERcolumn/replaceable DROP DEFAULT
--- 33,39 
  where replaceable class=PARAMETERaction/replaceable is one of:
  
  ADD [ COLUMN ] replaceable class=PARAMETERcolumn/replaceable replaceable class=PARAMETERtype/replaceable [ replaceable class=PARAMETERcolumn_constraint/replaceable [ ... ] ]
! DROP [ COLUMN ] [ IF EXISTS ] replaceable class=PARAMETERcolumn/replaceable [ RESTRICT | CASCADE ]
  ALTER [ COLUMN ] replaceable class=PARAMETERcolumn/replaceable [ SET DATA ] TYPE replaceable class=PARAMETERtype/replaceable [ USING replaceable class=PARAMETERexpression/replaceable ]
  ALTER [ COLUMN ] replaceable class=PARAMETERcolumn/replaceable SET DEFAULT replaceable class=PARAMETERexpression/replaceable
  ALTER [ COLUMN ] replaceable class=PARAMETERcolumn/replaceable DROP DEFAULT
*** where replaceable class=PARAMETERact
*** 41,47 
  ALTER [ COLUMN ] replaceable class=PARAMETERcolumn/replaceable SET STATISTICS replaceable class=PARAMETERinteger/replaceable
  ALTER [ COLUMN ] replaceable class=PARAMETERcolumn/replaceable SET STORAGE { PLAIN | EXTERNAL | EXTENDED | MAIN }
  ADD replaceable class=PARAMETERtable_constraint/replaceable
! DROP CONSTRAINT replaceable class=PARAMETERconstraint_name/replaceable [ RESTRICT | CASCADE ]
  DISABLE TRIGGER [ replaceable class=PARAMETERtrigger_name/replaceable | ALL | USER ]
  ENABLE TRIGGER [ replaceable class=PARAMETERtrigger_name/replaceable | ALL | USER ]
  ENABLE REPLICA TRIGGER replaceable class=PARAMETERtrigger_name/replaceable
--- 41,47 
  ALTER [ COLUMN ] replaceable class=PARAMETERcolumn/replaceable SET STATISTICS replaceable class=PARAMETERinteger/replaceable
  ALTER [ COLUMN ] replaceable class=PARAMETERcolumn/replaceable SET STORAGE { PLAIN | EXTERNAL | EXTENDED | MAIN }
  ADD replaceable class=PARAMETERtable_constraint/replaceable
! DROP CONSTRAINT [ IF EXISTS ]  replaceable class=PARAMETERconstraint_name/replaceable [ RESTRICT | CASCADE ]
  DISABLE TRIGGER [ replaceable class=PARAMETERtrigger_name/replaceable | ALL | USER ]
  ENABLE TRIGGER [ replaceable class=PARAMETERtrigger_name/replaceable | ALL | USER ]
  ENABLE REPLICA TRIGGER replaceable class=PARAMETERtrigger_name/replaceable
*** where replaceable class=PARAMETERact
*** 82,88 
 /varlistentry
  
 varlistentry
! termliteralDROP COLUMN/literal/term

Re: [HACKERS] conditional dropping of columns/constraints

2009-05-06 Thread Andres Freund 

Hi,

On 05/04/2009 04:10 PM, Andres Freund wrote:

Would a patch adding 'IF EXISTS' support to:
- ALTER TABLE ... DROP COLUMN
- ALTER TABLE ... DROP CONSTRAINT
possibly be accepted?

A first version of a patch is attached:
- allows [ IF EXISTS ] for both, conditional dropping of columns and 
constraints

- adds two tiny additions to the alter_table regression suite
- adds minimal documentation (my wording might be completely off)

As this is my first patch to PG I am happy with most sort of feedback.


Andres
diff --git a/doc/src/sgml/ref/alter_table.sgml b/doc/src/sgml/ref/alter_table.sgml
index fe3f388..9678236 100644
*** a/doc/src/sgml/ref/alter_table.sgml
--- b/doc/src/sgml/ref/alter_table.sgml
*** ALTER TABLE replaceable class=PARAMETE
*** 33,39 
  where replaceable class=PARAMETERaction/replaceable is one of:
  
  ADD [ COLUMN ] replaceable class=PARAMETERcolumn/replaceable replaceable class=PARAMETERtype/replaceable [ replaceable class=PARAMETERcolumn_constraint/replaceable [ ... ] ]
! DROP [ COLUMN ] replaceable class=PARAMETERcolumn/replaceable [ RESTRICT | CASCADE ]
  ALTER [ COLUMN ] replaceable class=PARAMETERcolumn/replaceable [ SET DATA ] TYPE replaceable class=PARAMETERtype/replaceable [ USING replaceable class=PARAMETERexpression/replaceable ]
  ALTER [ COLUMN ] replaceable class=PARAMETERcolumn/replaceable SET DEFAULT replaceable class=PARAMETERexpression/replaceable
  ALTER [ COLUMN ] replaceable class=PARAMETERcolumn/replaceable DROP DEFAULT
--- 33,39 
  where replaceable class=PARAMETERaction/replaceable is one of:
  
  ADD [ COLUMN ] replaceable class=PARAMETERcolumn/replaceable replaceable class=PARAMETERtype/replaceable [ replaceable class=PARAMETERcolumn_constraint/replaceable [ ... ] ]
! DROP [ COLUMN ] [ IF EXISTS ] replaceable class=PARAMETERcolumn/replaceable [ RESTRICT | CASCADE ]
  ALTER [ COLUMN ] replaceable class=PARAMETERcolumn/replaceable [ SET DATA ] TYPE replaceable class=PARAMETERtype/replaceable [ USING replaceable class=PARAMETERexpression/replaceable ]
  ALTER [ COLUMN ] replaceable class=PARAMETERcolumn/replaceable SET DEFAULT replaceable class=PARAMETERexpression/replaceable
  ALTER [ COLUMN ] replaceable class=PARAMETERcolumn/replaceable DROP DEFAULT
*** where replaceable class=PARAMETERact
*** 41,47 
  ALTER [ COLUMN ] replaceable class=PARAMETERcolumn/replaceable SET STATISTICS replaceable class=PARAMETERinteger/replaceable
  ALTER [ COLUMN ] replaceable class=PARAMETERcolumn/replaceable SET STORAGE { PLAIN | EXTERNAL | EXTENDED | MAIN }
  ADD replaceable class=PARAMETERtable_constraint/replaceable
! DROP CONSTRAINT replaceable class=PARAMETERconstraint_name/replaceable [ RESTRICT | CASCADE ]
  DISABLE TRIGGER [ replaceable class=PARAMETERtrigger_name/replaceable | ALL | USER ]
  ENABLE TRIGGER [ replaceable class=PARAMETERtrigger_name/replaceable | ALL | USER ]
  ENABLE REPLICA TRIGGER replaceable class=PARAMETERtrigger_name/replaceable
--- 41,47 
  ALTER [ COLUMN ] replaceable class=PARAMETERcolumn/replaceable SET STATISTICS replaceable class=PARAMETERinteger/replaceable
  ALTER [ COLUMN ] replaceable class=PARAMETERcolumn/replaceable SET STORAGE { PLAIN | EXTERNAL | EXTENDED | MAIN }
  ADD replaceable class=PARAMETERtable_constraint/replaceable
! DROP CONSTRAINT [ IF EXISTS ]  replaceable class=PARAMETERconstraint_name/replaceable [ RESTRICT | CASCADE ]
  DISABLE TRIGGER [ replaceable class=PARAMETERtrigger_name/replaceable | ALL | USER ]
  ENABLE TRIGGER [ replaceable class=PARAMETERtrigger_name/replaceable | ALL | USER ]
  ENABLE REPLICA TRIGGER replaceable class=PARAMETERtrigger_name/replaceable
*** where replaceable class=PARAMETERact
*** 82,88 
 /varlistentry
  
 varlistentry
! termliteralDROP COLUMN/literal/term
  listitem
   para
This form drops a column from a table.  Indexes and
--- 82,88 
 /varlistentry
  
 varlistentry
! termliteralDROP COLUMN [ IF EXISTS ]/literal/term
  listitem
   para
This form drops a column from a table.  Indexes and
*** where replaceable class=PARAMETERact
*** 90,95 
--- 90,98 
dropped as well.  You will need to say literalCASCADE/ if
anything outside the table depends on the column, for example,
foreign key references or views.
+   If literalIF EXISTS/literal is specified, no error is thrown
+   if the specified column does not exist. A notice is issued in
+   this case.
   /para
  /listitem
 /varlistentry
*** where replaceable class=PARAMETERact
*** 192,201 
 /varlistentry
  
 varlistentry
! termliteralDROP CONSTRAINT/literal/term
  listitem
   para
This form drops the specified constraint on a table.
   /para
  /listitem
 /varlistentry
--- 195,207 
 /varlistentry

Re: [HACKERS] conditional dropping of columns/constraints

2009-05-06 Thread Tom Lane 
Andres Freund and...@anarazel.de writes:
 As this is my first patch to PG I am happy with most sort of feedback.

Please add your patch to the commit-fest queue here:
http://wiki.postgresql.org/wiki/CommitFestInProgress

Since we are still busy with 8.4 beta, it's unlikely that anyone will
take a close look until the next commit fest begins.  FWIW, I took a
very fast look through the patch and thought it was at least touching
the right places, except I think you missed equalfuncs.c.  (It'd be a
good idea to grep for all uses of AlterTableCmd struct to see if you
missed anything else.)  I don't have time now to look closer or do any
testing.

regards, tom lane

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Re: [HACKERS] conditional dropping of columns/constraints

2009-05-05 Thread Chris Browne 
robertmh...@gmail.com (Robert Haas) writes:
 On Mon, May 4, 2009 at 10:10 AM, Andres Freund and...@anarazel.de wrote:
 Would a patch adding 'IF EXISTS' support to:
 - ALTER TABLE ... DROP COLUMN
 - ALTER TABLE ... DROP CONSTRAINT
 possibly be accepted?

 Having it makes the annoying task of writing/testing of schema-upgrade
 scripts a bit easier.

 Can't speak for the committers, but I've wished for this a time or two myself.

For constraints, it's easy enough to treat that as idempotent; it's no
big deal to drop and re-add a constraint.

For columns, I'd *much* more frequently be interested in
   ALTER TABLE ... ADD COLUMN IF NOT EXISTS ...

Note that this is distinctly NOT the same as:
   ALTER TABLE ... DROP COLUMN IF EXISTS ...
   ALTER TABLE ... ADD COLUMN ...
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Re: [HACKERS] conditional dropping of columns/constraints

2009-05-05 Thread Peter Eisentraut 
On Monday 04 May 2009 22:21:10 Chris Browne wrote:
 For constraints, it's easy enough to treat that as idempotent; it's no
 big deal to drop and re-add a constraint.

Not if the constraint is a primary key, for example.


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Re: [HACKERS] conditional dropping of columns/constraints

2009-05-05 Thread Andrew Dunstan 



Chris Browne wrote:

For columns, I'd *much* more frequently be interested in
   ALTER TABLE ... ADD COLUMN IF NOT EXISTS ...


  


We have debated CREATE ... IF NOT EXISTS in the past, and there is no 
consensus on what it should do, so we don't have it for any command. 
That is quite a different case from what's being asked for, and the two 
should not be conflated.


cheers

andrew

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Re: [HACKERS] conditional dropping of columns/constraints

2009-05-05 Thread Andres Freund 

Hi Chris,

On 05/04/2009 09:21 PM, Chris Browne wrote:

robertmh...@gmail.com (Robert Haas) writes:

On Mon, May 4, 2009 at 10:10 AM, Andres Freundand...@anarazel.de  wrote:

Would a patch adding 'IF EXISTS' support to:
- ALTER TABLE ... DROP COLUMN
- ALTER TABLE ... DROP CONSTRAINT
possibly be accepted?

Can't speak for the committers, but I've wished for this a time or two myself.

For constraints, it's easy enough to treat that as idempotent; it's no
big deal to drop and re-add a constraint.

For columns, I'd *much* more frequently be interested in
ALTER TABLE ... ADD COLUMN IF NOT EXISTS ...

Note that this is distinctly NOT the same as:
ALTER TABLE ... DROP COLUMN IF EXISTS ...
ALTER TABLE ... ADD COLUMN ...
Yes, I would like to have that myself - but this seems to open a way 
much bigger can of worms.
Also the problem solved by both suggestions are not completely congruent 
- so I thought better tackle the easier one first before starting a long 
and arduous discussion...


Andres

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Re: [HACKERS] conditional dropping of columns/constraints

2009-05-05 Thread Robert Haas 
On Tue, May 5, 2009 at 8:56 AM, Andrew Dunstan and...@dunslane.net wrote:
 We have debated CREATE ... IF NOT EXISTS in the past, and there is no
 consensus on what it should do, so we don't have it for any command. That is
 quite a different case from what's being asked for, and the two should not
 be conflated.

I must be missing something, because the semantics of CREATE ... IF
NOT EXISTS seem pretty well-defined to me, at least for any object
that has a name.  Check whether that name is in use; if not, create
the object per the specified definition.  Now for something like ALTER
TABLE ... ADD FOREIGN KEY I can see that there could be a problem.
That having been said, it's certain that CREATE IF NOT EXISTS is a
bigger foot-gun than DROP IF EXISTS, because after a succesful DROP IF
EXISTS the state of the object is known, whereas after CREATE IF NOT
EXISTS, it isn't (yes, it exists, but the definitions might not
match).  Still, that seems no reason not to implement it.  Right now,
I have a complex set of scripts which track the state of the database
to determine which DDL statements have already been applied.
Something like this would potentially simplify those scripts quite a
bit, so I'm much in favor.

On the other hand, I also agree with the point already made that these
are two different features, and we may as well focus on one at a time.

...Robert

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Re: [HACKERS] conditional dropping of columns/constraints

2009-05-05 Thread Tom Lane 
Robert Haas robertmh...@gmail.com writes:
 On Tue, May 5, 2009 at 8:56 AM, Andrew Dunstan and...@dunslane.net wrote:
 We have debated CREATE ... IF NOT EXISTS in the past, and there is no
 consensus on what it should do, so we don't have it for any command. That is
 quite a different case from what's being asked for, and the two should not
 be conflated.

 I must be missing something, because the semantics of CREATE ... IF
 NOT EXISTS seem pretty well-defined to me,

Please go read the prior threads (I think searching for CINE might
help, because we pretty shortly started abbreviating it like that).

regards, tom lane

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Re: [HACKERS] conditional dropping of columns/constraints

2009-05-05 Thread Andrew Dunstan 



Robert Haas wrote:

On Tue, May 5, 2009 at 8:56 AM, Andrew Dunstan and...@dunslane.net wrote:
  

We have debated CREATE ... IF NOT EXISTS in the past, and there is no
consensus on what it should do, so we don't have it for any command. That is
quite a different case from what's being asked for, and the two should not
be conflated.



I must be missing something, because the semantics of CREATE ... IF
NOT EXISTS seem pretty well-defined to me, at least for any object
that has a name.  Check whether that name is in use; if not, create
the object per the specified definition.  
  


And if it does exist but the definitions don't match? That's the issue 
on which there has not been consensus. You apparently thing the command 
should silently do nothing, but that's not what everyone thinks. (I have 
no very strong feelings on the subject - I'm just explaining the issue.)


cheers

andrew

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Re: [HACKERS] conditional dropping of columns/constraints

2009-05-04 Thread Andres Freund 

On 05/04/2009 04:10 PM, Andres Freund wrote:

Would a patch adding 'IF EXISTS' support to:
- ALTER TABLE ... DROP COLUMN
- ALTER TABLE ... DROP CONSTRAINT
possibly be accepted?

Having it makes the annoying task of writing/testing of schema-upgrade
scripts a bit easier.

Oh, and to any other sensible place given there are more?

Andres

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[HACKERS] conditional dropping of columns/constraints

2009-05-04 Thread Andres Freund 

Hi,

Would a patch adding 'IF EXISTS' support to:
- ALTER TABLE ... DROP COLUMN
- ALTER TABLE ... DROP CONSTRAINT
possibly be accepted?

Having it makes the annoying task of writing/testing of schema-upgrade 
scripts a bit easier.


Andres

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Re: [HACKERS] conditional dropping of columns/constraints

2009-05-04 Thread Robert Haas 
On Mon, May 4, 2009 at 10:10 AM, Andres Freund and...@anarazel.de wrote:
 Would a patch adding 'IF EXISTS' support to:
 - ALTER TABLE ... DROP COLUMN
 - ALTER TABLE ... DROP CONSTRAINT
 possibly be accepted?

 Having it makes the annoying task of writing/testing of schema-upgrade
 scripts a bit easier.

Can't speak for the committers, but I've wished for this a time or two myself.

...Robert

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