Обсуждение: Backslashitis
Hi,
I have a column declared as array of text. I can get a single backslash into one of the array elements by
update ... set mycol[1] = E'blah \\here'
If I try to update the whole array
update ... set mycol = E'{"blah \\here"}'
the backslash is missing. I can get two backslashes there.
Is there a good way to solve the problem, other than rewriting my update script to do array updates one element at a
time?
Regards
Wolfgang Hamann
I think you need to double the quotes. Its mentioned in the PG documention
Eg:-
postgres=# update array_test set name=E'{"meet\\\\ing"}';
UPDATE 2
postgres=# select * from array_test ;
name
---------------
{"meet\\ing"}
{"meet\\ing"}
(2 rows)
On Thu, Jun 14, 2012 at 1:47 PM, <hamann.w@t-online.de> wrote:
Hi,
I have a column declared as array of text. I can get a single backslash into one of the array elements by
update ... set mycol[1] = E'blah \\here'
If I try to update the whole array
update ... set mycol = E'{"blah \\here"}'
the backslash is missing. I can get two backslashes there.
Is there a good way to solve the problem, other than rewriting my update script to do array updates one element at a time?
Regards
Wolfgang Hamann
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hamann.w@t-online.de, 14.06.2012 10:17:
> Hi,
>
> I have a column declared as array of text. I can get a single backslash into one of the array elements by
> update ... set mycol[1] = E'blah \\here'
> If I try to update the whole array
> update ... set mycol = E'{"blah \\here"}'
> the backslash is missing. I can get two backslashes there.
> Is there a good way to solve the problem, other than rewriting my update script to do array updates one element at a
time?
>
Setting
standard_conforming_strings = true
should do the trick.
http://www.postgresql.org/docs/current/static/runtime-config-compatible.html#GUC-STANDARD-CONFORMING-STRINGS
In that case you don't need any escaping inside the string literals.
Regards
Thomas
On Thu, Jun 14, 2012 at 2:19 PM, Thomas Kellerer <spam_eater@gmx.net> wrote:
hamann.w@t-online.de, 14.06.2012 10:17:SettingHi,
I have a column declared as array of text. I can get a single backslash into one of the array elements by
update ... set mycol[1] = E'blah \\here'
If I try to update the whole array
update ... set mycol = E'{"blah \\here"}'
the backslash is missing. I can get two backslashes there.
Is there a good way to solve the problem, other than rewriting my update script to do array updates one element at a time?
standard_conforming_strings = true
should do the trick.
http://www.postgresql.org/docs/current/static/runtime-config-compatible.html#GUC-STANDARD-CONFORMING-STRINGS
In that case you don't need any escaping inside the string literals.
Regards
Thomas
Nope..
postgres=# show standard_conforming_strings ;
standard_conforming_strings
-----------------------------
on
(1 row)
postgres=# set standard_conforming_strings =on;
SET
postgres=# show standard_conforming_strings ;
standard_conforming_strings
-----------------------------
on
(1 row)
postgres=# update array_test set name=E'{"meet\\ing"}';
UPDATE 2
postgres=# select * from array_test ;
name
-----------
{meeting}
{meeting}
(2 rows)
Correct me, if anything wrong.
--Raghav
On 14 June 2012 10:03, Raghavendra <raghavendra.rao@enterprisedb.com> wrote:
>
> On Thu, Jun 14, 2012 at 2:19 PM, Thomas Kellerer <spam_eater@gmx.net> wrote:
>>
>> hamann.w@t-online.de, 14.06.2012 10:17:
>>
>>> Hi,
>>>
>>> I have a column declared as array of text. I can get a single backslash
>>> into one of the array elements by
>>> update ... set mycol[1] = E'blah \\here'
>>> If I try to update the whole array
>>> update ... set mycol = E'{"blah \\here"}'
>>> the backslash is missing. I can get two backslashes there.
>>> Is there a good way to solve the problem, other than rewriting my update
>>> script to do array updates one element at a time?
>>>
>>
>> Setting
>> standard_conforming_strings = true
>>
>> should do the trick.
>>
>>
>> http://www.postgresql.org/docs/current/static/runtime-config-compatible.html#GUC-STANDARD-CONFORMING-STRINGS
>>
>> In that case you don't need any escaping inside the string literals.
>>
>> Regards
>> Thomas
>>
>
> Nope..
>
> postgres=# show standard_conforming_strings ;
> standard_conforming_strings
> -----------------------------
> on
> (1 row)
> postgres=# set standard_conforming_strings =on;
> SET
> postgres=# show standard_conforming_strings ;
> standard_conforming_strings
> -----------------------------
> on
> (1 row)
> postgres=# update array_test set name=E'{"meet\\ing"}';
> UPDATE 2
> postgres=# select * from array_test ;
> name
> -----------
> {meeting}
> {meeting}
> (2 rows)
>
> Correct me, if anything wrong.
>
> --Raghav
>
With standard conforming strings on, you could use any of the following:
update foo set a= E'{"blah \\\\here"}';
update foo set a= '{"blah \\here"}';
update foo set a= ARRAY[E'blah \\here'];
update foo set a= ARRAY['blah \here'];
I tend to prefer the ARRAY[...] constructor syntax because it doesn't
require any additional escaping of individual elements.
http://www.postgresql.org/docs/current/static/sql-syntax-lexical.html#SQL-SYNTAX-STRINGS-ESCAPE
http://www.postgresql.org/docs/current/static/sql-expressions.html#SQL-SYNTAX-ARRAY-CONSTRUCTORS
Regards,
Dean
With standard conforming strings on, you could use any of the following:
update foo set a= E'{"blah \\\\here"}';
update foo set a= '{"blah \\here"}';
update foo set a= ARRAY[E'blah \\here'];
update foo set a= ARRAY['blah \here'];
I tend to prefer the ARRAY[...] constructor syntax because it doesn't
require any additional escaping of individual elements.
http://www.postgresql.org/docs/current/static/sql-syntax-lexical.html#SQL-SYNTAX-STRINGS-ESCAPE
http://www.postgresql.org/docs/current/static/sql-expressions.html#SQL-SYNTAX-ARRAY-CONSTRUCTORS
Regards,
Dean
Thanks