Thread: Can you help me with this query?

Can you help me with this query?

From

mike.griffin@mygenerationsoftware.com

Date:

15 June 2004, 01:48:45

The query below will return all of the foreign keys in the current schema,
I get the ForeignKey name as FK_NAME and both the primary and foreign
table's name and schema, now I just need the columns involved in the
foreign key itself, there is a column called confkey in pg_constraint and
it's an array?  It holds the column id


SELECT ct.oid, conname as FK_NAME, confkey, nl.nspname as PK_TABLE_SCHEMA,
cl.relname as PK_TABLE_NAME,
nr.nspname as FK_TABLE_SCHEMA, cr.relname as FK_TABLE_NAME, description
FROM pg_constraint ct
JOIN pg_class cl ON cl.oid=conrelid
JOIN pg_namespace nl ON nl.oid=cl.relnamespace
JOIN pg_class cr ON cr.oid=confrelid
JOIN pg_namespace nr ON nr.oid=cr.relnamespace
LEFT OUTER JOIN pg_description des ON des.objoid=ct.oid
WHERE contype='f'

Re: Can you help me with this query?

From

Joe Conway

Date:

15 June 2004, 03:42:42

mike.griffin@mygenerationsoftware.com wrote:
> The query below will return all of the foreign keys in the current schema,
> I get the ForeignKey name as FK_NAME and both the primary and foreign
> table's name and schema, now I just need the columns involved in the
> foreign key itself, there is a column called confkey in pg_constraint and
> it's an array?  It holds the column id

It is an array because foreign keys can have more than one participating
field -- how do you want that represented? Here's a way that you can get
an array of the participating field names, assuming you're using
Postgres 7.4.x:

create or replace function getattnames(oid, smallint[])
returns name[] as '
   select array(select attname from pg_attribute
                where attrelid = $1
                and attnum = any ($2))
' language sql;

SELECT cl.relname as TABLE_NAME,
        cr.relname as FK_TABLE_NAME,
        getattnames(ct.conrelid, ct.conkey) as TBL_ATTS,
        getattnames(ct.confrelid, ct.confkey) as FK_TBL_ATTS
FROM pg_constraint ct
JOIN pg_class cl ON cl.oid=conrelid
JOIN pg_namespace nl ON nl.oid=cl.relnamespace
JOIN pg_class cr ON cr.oid=confrelid
JOIN pg_namespace nr ON nr.oid=cr.relnamespace
LEFT OUTER JOIN pg_description des ON des.objoid=ct.oid
WHERE contype='f';

      table_name     |   fk_table_name    |  tbl_atts   | fk_tbl_atts
--------------------+--------------------+-------------+-------------
  rule_and_refint_t3 | rule_and_refint_t1 | {id3a,id3b} | {id1a,id1b}
  rule_and_refint_t3 | rule_and_refint_t2 | {id3a,id3c} | {id2a,id2c}
  fktable            | pktable            | {fk}        | {id}
  clstr_tst          | clstr_tst_s        | {b}         | {rf_a}
(4 rows)

HTH,

Joe

Re: Can you help me with this query?

From

Joe Conway

Date:

15 June 2004, 15:51:02

(please keep posts on the list so that others can follow along)

mike.griffin@mygenerationsoftware.com wrote:
> Joe, I'm sorry but I cannot create functions or anything like that, it's
> all has to be a select statement (or series of select statements). Users
> pull up our product and browse all the databases and scheme's and such, if
> we asked them to create functions or if we did it through calls it would
> be intrusive.
>
> I tried to flatten out the function into a nested query but couldn't quite
> get it right, is it possible to embed the select statement in the function
> into the main select statement?
>

SELECT cl.relname as TABLE_NAME,
         cr.relname as FK_TABLE_NAME,
         array(select attname from pg_attribute
               where attrelid = ct.conrelid
               and attnum = any (ct.conkey)) as TBL_ATTS,
         array(select attname from pg_attribute
               where attrelid = ct.confrelid
               and attnum = any (ct.confkey)) as FK_TBL_ATTS
FROM pg_constraint ct
JOIN pg_class cl ON cl.oid=conrelid
JOIN pg_namespace nl ON nl.oid=cl.relnamespace
JOIN pg_class cr ON cr.oid=confrelid
JOIN pg_namespace nr ON nr.oid=cr.relnamespace
LEFT OUTER JOIN pg_description des ON des.objoid=ct.oid
WHERE contype='f';

      table_name     |   fk_table_name    |  tbl_atts   | fk_tbl_atts
--------------------+--------------------+-------------+-------------
  rule_and_refint_t3 | rule_and_refint_t1 | {id3a,id3b} | {id1a,id1b}
  rule_and_refint_t3 | rule_and_refint_t2 | {id3a,id3c} | {id2a,id2c}
  fktable            | pktable            | {fk}        | {id}
  clstr_tst          | clstr_tst_s        | {b}         | {rf_a}
(4 rows)

HTH,

Joe

Re: Can you help me with this query?

From

mike.griffin@mygenerationsoftware.com

Date:

15 June 2004, 16:19:58

Joe, I'm sorry but I cannot create functions or anything like that, it's
all has to be a select statement (or series of select statements). Users
pull up our product and browse all the databases and scheme's and such, if
we asked them to create functions or if we did it through calls it would
be intrusive.

I tried to flatten out the function into a nested query but couldn't quite
get it right, is it possible to embed the select statement in the function
into the main select statement?

- Mike


> mike.griffin@mygenerationsoftware.com wrote:
>> The query below will return all of the foreign keys in the current
>> schema,
>> I get the ForeignKey name as FK_NAME and both the primary and foreign
>> table's name and schema, now I just need the columns involved in the
>> foreign key itself, there is a column called confkey in pg_constraint
>> and
>> it's an array?  It holds the column id
>
> It is an array because foreign keys can have more than one participating
> field -- how do you want that represented? Here's a way that you can get
> an array of the participating field names, assuming you're using
> Postgres 7.4.x:
>
> create or replace function getattnames(oid, smallint[])
> returns name[] as '
>    select array(select attname from pg_attribute
>                 where attrelid = $1
>                 and attnum = any ($2))
> ' language sql;
>
> SELECT cl.relname as TABLE_NAME,
>         cr.relname as FK_TABLE_NAME,
>         getattnames(ct.conrelid, ct.conkey) as TBL_ATTS,
>         getattnames(ct.confrelid, ct.confkey) as FK_TBL_ATTS
> FROM pg_constraint ct
> JOIN pg_class cl ON cl.oid=conrelid
> JOIN pg_namespace nl ON nl.oid=cl.relnamespace
> JOIN pg_class cr ON cr.oid=confrelid
> JOIN pg_namespace nr ON nr.oid=cr.relnamespace
> LEFT OUTER JOIN pg_description des ON des.objoid=ct.oid
> WHERE contype='f';
>
>       table_name     |   fk_table_name    |  tbl_atts   | fk_tbl_atts
> --------------------+--------------------+-------------+-------------
>   rule_and_refint_t3 | rule_and_refint_t1 | {id3a,id3b} | {id1a,id1b}
>   rule_and_refint_t3 | rule_and_refint_t2 | {id3a,id3c} | {id2a,id2c}
>   fktable            | pktable            | {fk}        | {id}
>   clstr_tst          | clstr_tst_s        | {b}         | {rf_a}
> (4 rows)
>
> HTH,
>
> Joe
>
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>

Re: Can you help me with this query?

From

Brendan Jurd

Date:

16 June 2004, 09:40:13

Hi Mike,<br /><br /> If your foreign keys are all single-attribute, you can solve the problem easily by only using the
firstelement of each key.<br /><br /> I like to use the following view to examine foreign keys:<br /><br /> CREATE VIEW
fkeyAS<br />  SELECT t.relname AS tab, c.attname AS col, ft.relname AS ftab, fc.attname AS fcol<br />  FROM
pg_constraintfk<br />   INNER JOIN pg_class t ON fk.conrelid=t.oid<br />   INNER JOIN pg_attribute c ON
fk.conkey[1]=c.attnumAND c.attrelid=t.oid<br />   INNER JOIN pg_class ft ON fk.confrelid=ft.oid<br />   INNER JOIN
pg_attributefc ON fk.confkey[1]=fc.attnum AND fc.attrelid=ft.oid<br />  WHERE fk.contype = 'f'<br /> ;<br /><br /> Note
"confkey[1]=..."in the join condition.  Of course, if the FK uses multiple columns at either end the whole thing
becomesrapidly useless.  <br /><br /> HTH<br /><br /> BJ<br /><br /><br /><a class="moz-txt-link-abbreviated"
href="mailto:mike.griffin@mygenerationsoftware.com">mike.griffin@mygenerationsoftware.com</a>wrote: <blockquote
cite="mid46038.168.215.73.114.1087316384.squirrel@168.215.73.114"type="cite"><pre wrap="">Joe, I'm sorry but I cannot
createfunctions or anything like that, it's
 
all has to be a select statement (or series of select statements). Users
pull up our product and browse all the databases and scheme's and such, if
we asked them to create functions or if we did it through calls it would
be intrusive.

I tried to flatten out the function into a nested query but couldn't quite
get it right, is it possible to embed the select statement in the function
into the main select statement?

- Mike

 </pre><blockquote type="cite"><pre wrap=""><a class="moz-txt-link-abbreviated"
href="mailto:mike.griffin@mygenerationsoftware.com">mike.griffin@mygenerationsoftware.com</a>wrote:   </pre><blockquote
type="cite"><prewrap="">The query below will return all of the foreign keys in the current
 
schema,
I get the ForeignKey name as FK_NAME and both the primary and foreign
table's name and schema, now I just need the columns involved in the
foreign key itself, there is a column called confkey in pg_constraint
and
it's an array?  It holds the column id     </pre></blockquote><pre wrap="">It is an array because foreign keys can have
morethan one participating
 
field -- how do you want that represented? Here's a way that you can get
an array of the participating field names, assuming you're using
Postgres 7.4.x:

create or replace function getattnames(oid, smallint[])
returns name[] as '  select array(select attname from pg_attribute               where attrelid = $1               and
attnum= any ($2))
 
' language sql;

SELECT cl.relname as TABLE_NAME,       cr.relname as FK_TABLE_NAME,       getattnames(ct.conrelid, ct.conkey) as
TBL_ATTS,      getattnames(ct.confrelid, ct.confkey) as FK_TBL_ATTS
 
FROM pg_constraint ct
JOIN pg_class cl ON cl.oid=conrelid
JOIN pg_namespace nl ON nl.oid=cl.relnamespace
JOIN pg_class cr ON cr.oid=confrelid
JOIN pg_namespace nr ON nr.oid=cr.relnamespace
LEFT OUTER JOIN pg_description des ON des.objoid=ct.oid
WHERE contype='f';
     table_name     |   fk_table_name    |  tbl_atts   | fk_tbl_atts
--------------------+--------------------+-------------+------------- rule_and_refint_t3 | rule_and_refint_t1 |
{id3a,id3b}| {id1a,id1b} rule_and_refint_t3 | rule_and_refint_t2 | {id3a,id3c} | {id2a,id2c} fktable            |
pktable           | {fk}        | {id} clstr_tst          | clstr_tst_s        | {b}         | {rf_a}
 
(4 rows)

HTH,

Joe

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   </pre></blockquote><pre wrap="">


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Re: Can you help me with this query?

From

"Nick Barr"

Date:

16 June 2004, 10:22:53

<snip>

>
> create or replace function getattnames(oid, smallint[])
> returns name[] as '
>    select array(select attname from pg_attribute
>                 where attrelid = $1
>                 and attnum = any ($2))
> ' language sql;
>
> SELECT cl.relname as TABLE_NAME,
>         cr.relname as FK_TABLE_NAME,
>         getattnames(ct.conrelid, ct.conkey) as TBL_ATTS,
>         getattnames(ct.confrelid, ct.confkey) as FK_TBL_ATTS
> FROM pg_constraint ct
> JOIN pg_class cl ON cl.oid=conrelid
> JOIN pg_namespace nl ON nl.oid=cl.relnamespace
> JOIN pg_class cr ON cr.oid=confrelid
> JOIN pg_namespace nr ON nr.oid=cr.relnamespace
> LEFT OUTER JOIN pg_description des ON des.objoid=ct.oid
> WHERE contype='f';
>

How about:

SELECT cl.relname as TABLE_NAME,
        cr.relname as FK_TABLE_NAME,
 (select array(select attname from pg_attribute
  where attrelid = ct.conrelid
  and attnum = any (ct.conkey))) AS TBL_ATTS,
 (select array(select attname from pg_attribute
  where attrelid = ct.confrelid
  and attnum = any (ct.confkey))) AS FK_TBL_ATTS
FROM pg_constraint ct
JOIN pg_class cl ON cl.oid=conrelid
JOIN pg_namespace nl ON nl.oid=cl.relnamespace
JOIN pg_class cr ON cr.oid=confrelid
JOIN pg_namespace nr ON nr.oid=cr.relnamespace
LEFT OUTER JOIN pg_description des ON des.objoid=ct.oid
WHERE contype='f';

Note the function is no longer there ;-)

Nick

Re: Can you help me with this query?

From

mike.griffin@mygenerationsoftware.com

Date:

18 June 2004, 01:33:18

That doesn't complile, I don't think you can use a nested select where a
column goes?  I get an error yelping about one of the select statements,
did you test it out?  I'm using pgAdmin and don't think that it is the
problem?


> How about:
>
> SELECT cl.relname as TABLE_NAME,
>         cr.relname as FK_TABLE_NAME,
>  (select array(select attname from pg_attribute
>   where attrelid = ct.conrelid
>   and attnum = any (ct.conkey))) AS TBL_ATTS,
>  (select array(select attname from pg_attribute
>   where attrelid = ct.confrelid
>   and attnum = any (ct.confkey))) AS FK_TBL_ATTS
> FROM pg_constraint ct
> JOIN pg_class cl ON cl.oid=conrelid
> JOIN pg_namespace nl ON nl.oid=cl.relnamespace
> JOIN pg_class cr ON cr.oid=confrelid
> JOIN pg_namespace nr ON nr.oid=cr.relnamespace
> LEFT OUTER JOIN pg_description des ON des.objoid=ct.oid
> WHERE contype='f';
>
> Note the function is no longer there ;-)
>
> Nick
>
>
>
>
>
>
>
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