Thread: Tsearch2: casting text to tsquery
Hello,
I have a question that arose while using tsearch on a large database
of book information.
In order to inject unstemmed + stemmed versions of searchstrings into
a query we want to cast an expression of type text to tsquery.
Unfortunately
SELECT 'word'::tsquery
(where the literal 'word' is of type 'unknown' seemingly) works just
fine while e.g.
SELECT ('word' || '&fullword')::tsquery
or, simpler
SELECT 'word&fullword'::text::tsquery
gives
ERROR: cannot cast type text to tsearch2.tsquery
How can we work around that? Thanks for any help
Sincerely yours
Alexander Presber
On Wed, 16 Nov 2005, Alexander Presber wrote:
> Hello,
>
> I have a question that arose while using tsearch on a large database of book
> information.
>
> In order to inject unstemmed + stemmed versions of searchstrings into a query
> we want to cast an expression of type text to tsquery.
> Unfortunately
>
> SELECT 'word'::tsquery
>
> (where the literal 'word' is of type 'unknown' seemingly) works just fine
> while e.g.
>
> SELECT ('word' || '&fullword')::tsquery
>
> or, simpler
>
> SELECT 'word&fullword'::text::tsquery
>
> gives
>
> ERROR: cannot cast type text to tsearch2.tsquery
>
> How can we work around that? Thanks for any help
no workaround needed. to_tsquery provides everything you need. If you
want fancy-shmancy solution you could always write wrapper around tsquery, but
I doubt you enter queries by hand, so why do you bothering ?
>
> Sincerely yours
> Alexander Presber
>
>
>
>
> ---------------------------(end of broadcast)---------------------------
> TIP 6: explain analyze is your friend
Regards,
Oleg
_____________________________________________________________
Oleg Bartunov, sci.researcher, hostmaster of AstroNet,
Sternberg Astronomical Institute, Moscow University (Russia)
Internet: oleg@sai.msu.su, http://www.sai.msu.su/~megera/
phone: +007(095)939-16-83, +007(095)939-23-83
Am 16.11.2005 um 13:52 schrieb Oleg Bartunov:
> On Wed, 16 Nov 2005, Alexander Presber wrote:
>
>> Hello,
>>
>> I have a question that arose while using tsearch on a large
>> database of book information.
>>
>> In order to inject unstemmed + stemmed versions of searchstrings
>> into a query we want to cast an expression of type text to tsquery.
>> Unfortunately
>>
>> SELECT 'word'::tsquery
>>
>> (where the literal 'word' is of type 'unknown' seemingly) works
>> just fine while e.g.
>>
>> SELECT ('word' || '&fullword')::tsquery
>>
>> or, simpler
>>
>> SELECT 'word&fullword'::text::tsquery
>>
>> gives
>>
>> ERROR: cannot cast type text to tsearch2.tsquery
>>
>> How can we work around that? Thanks for any help
>
> no workaround needed. to_tsquery provides everything you need. If
> you want fancy-shmancy solution you could always write wrapper
> around tsquery, but
> I doubt you enter queries by hand, so why do you bothering ?
No. No fancy-shmancy solution needed, just one that works.
I do not see a way to include both a stemmed and unstemmed version of
a string into a tsquery.
Can you give an example, please?
Thanks
Alex
P.S. I have read the documentation (twice.)
>>
>> Sincerely yours
>> Alexander Presber
>>
>>
>>
>>
>> ---------------------------(end of
>> broadcast)---------------------------
>> TIP 6: explain analyze is your friend
>
> Regards,
> Oleg
> _____________________________________________________________
> Oleg Bartunov, sci.researcher, hostmaster of AstroNet,
> Sternberg Astronomical Institute, Moscow University (Russia)
> Internet: oleg@sai.msu.su, http://www.sai.msu.su/~megera/
> phone: +007(095)939-16-83, +007(095)939-23-83
On Wed, 16 Nov 2005, Alexander Presber wrote:
>
> Am 16.11.2005 um 13:52 schrieb Oleg Bartunov:
>
>> On Wed, 16 Nov 2005, Alexander Presber wrote:
>>
>>> Hello,
>>>
>>> I have a question that arose while using tsearch on a large database of
>>> book information.
>>>
>>> In order to inject unstemmed + stemmed versions of searchstrings into a
>>> query we want to cast an expression of type text to tsquery.
>>> Unfortunately
>>>
>>> SELECT 'word'::tsquery
>>>
>>> (where the literal 'word' is of type 'unknown' seemingly) works just fine
>>> while e.g.
>>>
>>> SELECT ('word' || '&fullword')::tsquery
>>>
>>> or, simpler
>>>
>>> SELECT 'word&fullword'::text::tsquery
>>>
>>> gives
>>>
>>> ERROR: cannot cast type text to tsearch2.tsquery
>>>
>>> How can we work around that? Thanks for any help
>>
>> no workaround needed. to_tsquery provides everything you need. If you want
>> fancy-shmancy solution you could always write wrapper around tsquery, but
>> I doubt you enter queries by hand, so why do you bothering ?
>
> No. No fancy-shmancy solution needed, just one that works.
>
> I do not see a way to include both a stemmed and unstemmed version of a
> string into a tsquery.
> Can you give an example, please?
This is quite different question and Teodor has already answered you -
use different configurations. But I'm wondering why do you need that.
>
> Thanks
> Alex
>
> P.S. I have read the documentation (twice.)
>
>>>
>>> Sincerely yours
>>> Alexander Presber
>>>
>>>
>>>
>>>
>>> ---------------------------(end of broadcast)---------------------------
>>> TIP 6: explain analyze is your friend
>>
>> Regards,
>> Oleg
>> _____________________________________________________________
>> Oleg Bartunov, sci.researcher, hostmaster of AstroNet,
>> Sternberg Astronomical Institute, Moscow University (Russia)
>> Internet: oleg@sai.msu.su, http://www.sai.msu.su/~megera/
>> phone: +007(095)939-16-83, +007(095)939-23-83
>
>
> ---------------------------(end of broadcast)---------------------------
> TIP 9: In versions below 8.0, the planner will ignore your desire to
> choose an index scan if your joining column's datatypes do not
> match
Regards,
Oleg
_____________________________________________________________
Oleg Bartunov, sci.researcher, hostmaster of AstroNet,
Sternberg Astronomical Institute, Moscow University (Russia)
Internet: oleg@sai.msu.su, http://www.sai.msu.su/~megera/
phone: +007(095)939-16-83, +007(095)939-23-83