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Re: ALTER TABLE and adding FK Constraints - Assistance No longer needed - Mailing list pgsql-general

From	Michael Black
Subject	Re: ALTER TABLE and adding FK Constraints - Assistance No longer needed
Date	March 29, 2009 15:26:33
Msg-id	BLU144-W304FC41019E6963A26682FFA8C0@phx.gbl Whole thread Raw
In response to	ALTER TABLE and adding FK Constraints - Assistance Requested (Michael Black <michaelblack75052@hotmail.com>)
List	pgsql-general

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Thanks to all that responded. I got it figured out. The one I was testing did not have the associated table created yet (error message did not point me to a solution). Created the referenced table and it worked like a chump, er champ.

Michael

From: michaelblack75052@hotmail.com
To: pgsql-general@postgresql.org
Subject: [GENERAL] ALTER TABLE and adding FK Constraints - Assistance Requested
Date: Sun, 29 Mar 2009 15:04:28 +0000

.ExternalClass .EC_hmmessage P {padding:0px;} .ExternalClass body.EC_hmmessage {font-size:10pt;font-family:Verdana;} First, I am relatively new to postgres, but have been using database (design not administering) for about 20 years (you would think that I could figure this out - lol). At an rate, I am trying to create tables that have forgein keys via a script. What happens is if the table that is referred to in the forgeing key does not exist, the table fails to create. Undertandable. So what I need to do is create all the tables and then go back and alter the tables by adding the forgein key constraint. I got that. But what I am looking for is the correct syntax to add the forgein key constrant. I have tried "ALTER TABLE <name> CONSTRANT <constraint description>" and "ALTER TABLE <name> ADD CONSTRANT <constraint description>". But both fail.

Yes I am being lazy. I should go through the script and create the tables that are referenced first then the ones with the forgein key. But I also need to know this in the even the schema changes in the future and more constratins are necessary. I have looked at the ALTER TABLE syntax on postgres but it refers back to the CREATE TABLE function.

Michael

Date: Sun, 29 Mar 2009 13:58:30 +0200
Subject: [GENERAL] Fwd: concatenate and use as field
From: raf.news@gmail.com
To: pgsql-general@postgresql.org

Hi,

i have a character varying variable and i concatenate with some other variable, using the '||' operator.
the result of this concatenation should be the name of a column in my table.

however i don't know how to tell that this new concatenated string is a column name.
how to do it ?
thanks.

in fact i'm trying to do the following thing:

select id, theme_ || $1 from themes;

and based on the parameter my stored procedure has received, it should create something like that:
select id, theme_eng from themes;

if $1 = 'eng'

I think i'm a good way, but i still have a problem with the performance.
when i call my stored procedure, it can take 0.1 s to 3.5 seconds to execute it on local computer.
How can i improve it ?

here is my stored procedure:
CREATE OR REPLACE FUNCTION sewe.get_category_and_amount(character varying)
RETURNS SETOF category_amount AS
$BODY$
    DECLARE
        inLanguage ALIAS FOR $1;
        outCategoryAndAmount category_amount;

        Lang character varying :='';
    BEGIN
        IF inLanguage = null OR inLanguage = '' THEN
            Lang := 'eng';
        ELSE
            Lang := inLanguage;
        END IF;

        FOR outCategoryAndAmount IN
            EXECUTE 'SELECT id, theme_name_' || Lang || ' FROM themes WHERE parent_theme IS NULL ORDER BY theme_name_' || Lang || ' ASC'
        LOOP
            RETURN NEXT outCategoryAndAmount;
        END LOOP;
    END;
$BODY$
LANGUAGE 'plpgsql' VOLATILE
COST 100
ROWS 1000;

pgsql-general by date:

From: ries van Twisk
Date: 29 March 2009, 15:13:32
Subject: Re: ALTER TABLE and adding FK Constraints - Assistance Requested

From: SydMosh
Date: 29 March 2009, 17:09:20
Subject: Doubt about SELECT

Re: ALTER TABLE and adding FK Constraints - Assistance No longer needed - Mailing list pgsql-general

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