Delimited identifier brhavior

Hi,

I' wondering if following delimited identifier brhavior is correct or
not:

test=# create table t1(i int);
create table t1(i int);
CREATE TABLE
test=# create table t1_foo(i int, j int);
create table t1_foo(i int, j int);
CREATE TABLE
test=# select * from t1;
select * from t1;
i
---
(0 rows)

test=# select * from t1_foo;
select * from t1_foo;
i | j
---+---
(0 rows)

test=# select * from "t1"_foo;
select * from "t1"_foo;
i
---
(0 rows)

It seems PostgreSQL thinks "t1"_foo is equivalent to t1. Is this an
expected behavior?
--
Tatsuo Ishii
SRA OSS, Inc. Japan
English: http://www.sraoss.co.jp/index_en.php
Japanese: http://www.sraoss.co.jp

Tatsuo Ishii <ishii(at)postgresql(dot)org> wrote:

> It seems PostgreSQL thinks "t1"_foo is equivalent to t1.

It thinks you've given "t1" an alias of "_foo" in that query, same
as if you'd had a space between "t1" and _foo.

-Kevin

Tatsuo Ishii wrote:
> test=# select * from "t1"_foo;
> select * from "t1"_foo;
> i
> ---
> (0 rows)
>
> It seems PostgreSQL thinks "t1"_foo is equivalent to t1. Is this an
> expected behavior?

That code looks badly written in any event. Delimiters should be put around
each part of an identifier or chain as a whole, such as:

select * from "t1_foo";

Or with schema-delimited objects, for example, any of these:

schema.table

"schema".table

schema."table"

"schema"."table"

Personally, I treat all of my identifiers as being case-sensitive. Knowing that
Pg treats non-delimited identifiers as being lowercase, I write undelimited when
the identifier is entirely lowercase, and I delimit ones that have any
uppercase. And by doing this consistently everything works correctly. Since
most of my identifiers are lowercase anyway, the code also reads cleanly in general.

-- Darren Duncan

On 11/11/2010 06:03 PM, Tatsuo Ishii wrote:
> Hi,
>
> I' wondering if following delimited identifier brhavior is correct or
> not:
>
> test=# create table t1(i int);
> create table t1(i int);
> CREATE TABLE
> test=# create table t1_foo(i int, j int);
> create table t1_foo(i int, j int);
> CREATE TABLE
> test=# select * from t1;
> select * from t1;
> i
> ---
> (0 rows)
>
> test=# select * from t1_foo;
> select * from t1_foo;
> i | j
> ---+---
> (0 rows)
>
> test=# select * from "t1"_foo;
> select * from "t1"_foo;
> i
> ---
> (0 rows)
>
> It seems PostgreSQL thinks "t1"_foo is equivalent to t1. Is this an
> expected behavior?

It's treating _foo as an alias in the query for t1. So the behaviour is
quite correct, I think.

cheers

andrew

>> It seems PostgreSQL thinks "t1"_foo is equivalent to t1.
>
> It thinks you've given "t1" an alias of "_foo" in that query, same
> as if you'd had a space between "t1" and _foo.

Oh, ok. I thought we always need at least one space character between
the table name and the alias.
--
Tatsuo Ishii
SRA OSS, Inc. Japan
English: http://www.sraoss.co.jp/index_en.php
Japanese: http://www.sraoss.co.jp