Re: Sqlectron

On 01/22/2018 02:57 PM, Brice Maron wrote:
> I'm new on this ML and I'm currently working on the multi-database
> client written using React and electron that you can see here :
> https://sqlectron.github.io/.
> especially on the postgresql part.
>
> I wanted to improve support on DDL extraction of the tables (like create
> table with all comments, PK, FK, ....) ; but it seems that there is no
> easy way to get a textual representation of this in sql, am i correct ?

If you start the command line psql client with the -E option it will
show you the internal queries used to gather and show information with
the "slash" commands, e.g. \d <tablename>

Here is what it looks like:

8<--------------------------
psql -E test
psql (10.1)
Type "help" for help.

test=# \d foo
********* QUERY **********
SELECT c.oid,
n.nspname,
c.relname
FROM pg_catalog.pg_class c
LEFT JOIN pg_catalog.pg_namespace n ON n.oid = c.relnamespace
WHERE c.relname ~ '^(foo)$'
AND pg_catalog.pg_table_is_visible(c.oid)
ORDER BY 2, 3;
**************************

********* QUERY **********
SELECT c.relchecks, c.relkind, c.relhasindex, c.relhasrules,
c.relhastriggers, c.relrowsecurity, c.relforcerowsecurity, c.relhasoids,
'', c.reltablespace, CASE WHEN c.reloftype = 0 THEN '' ELSE
c.reloftype::pg_catalog.regtype::pg_catalog.text END, c.relpersistence,
c.relreplident
FROM pg_catalog.pg_class c
LEFT JOIN pg_catalog.pg_class tc ON (c.reltoastrelid = tc.oid)
WHERE c.oid = '16410';
**************************

********* QUERY **********
SELECT a.attname,
pg_catalog.format_type(a.atttypid, a.atttypmod),
(SELECT substring(pg_catalog.pg_get_expr(d.adbin, d.adrelid) for 128)
FROM pg_catalog.pg_attrdef d
WHERE d.adrelid = a.attrelid AND d.adnum = a.attnum AND a.atthasdef),
a.attnotnull, a.attnum,
(SELECT c.collname FROM pg_catalog.pg_collation c, pg_catalog.pg_type t
WHERE c.oid = a.attcollation AND t.oid = a.atttypid AND
a.attcollation <> t.typcollation) AS attcollation,
a.attidentity,
NULL AS indexdef,
NULL AS attfdwoptions
FROM pg_catalog.pg_attribute a
WHERE a.attrelid = '16410' AND a.attnum > 0 AND NOT a.attisdropped
ORDER BY a.attnum;
**************************

********* QUERY **********
SELECT inhparent::pg_catalog.regclass,
pg_catalog.pg_get_expr(c.relpartbound, inhrelid)
FROM pg_catalog.pg_class c JOIN pg_catalog.pg_inherits i ON c.oid = inhrelid
WHERE c.oid = '16410' AND c.relispartition;
**************************

********* QUERY **********
SELECT pol.polname, pol.polpermissive,
CASE WHEN pol.polroles = '{0}' THEN NULL ELSE
pg_catalog.array_to_string(array(select rolname from pg_catalog.pg_roles
where oid = any (pol.polroles) order by 1),',') END,
pg_catalog.pg_get_expr(pol.polqual, pol.polrelid),
pg_catalog.pg_get_expr(pol.polwithcheck, pol.polrelid),
CASE pol.polcmd
WHEN 'r' THEN 'SELECT'
WHEN 'a' THEN 'INSERT'
WHEN 'w' THEN 'UPDATE'
WHEN 'd' THEN 'DELETE'
END AS cmd
FROM pg_catalog.pg_policy pol
WHERE pol.polrelid = '16410' ORDER BY 1;
**************************

********* QUERY **********
SELECT oid, stxrelid::pg_catalog.regclass,
stxnamespace::pg_catalog.regnamespace AS nsp, stxname,
(SELECT pg_catalog.string_agg(pg_catalog.quote_ident(attname),', ')
FROM pg_catalog.unnest(stxkeys) s(attnum)
JOIN pg_catalog.pg_attribute a ON (stxrelid = a.attrelid AND
a.attnum = s.attnum AND NOT attisdropped)) AS columns,
'd' = any(stxkind) AS ndist_enabled,
'f' = any(stxkind) AS deps_enabled
FROM pg_catalog.pg_statistic_ext stat WHERE stxrelid = '16410'
ORDER BY 1;
**************************

********* QUERY **********
SELECT pubname
FROM pg_catalog.pg_publication p
JOIN pg_catalog.pg_publication_rel pr ON p.oid = pr.prpubid
WHERE pr.prrelid = '16410'
UNION ALL
SELECT pubname
FROM pg_catalog.pg_publication p
WHERE p.puballtables AND pg_catalog.pg_relation_is_publishable('16410')
ORDER BY 1;
**************************

********* QUERY **********
SELECT c.oid::pg_catalog.regclass FROM pg_catalog.pg_class c,
pg_catalog.pg_inherits i WHERE c.oid=i.inhparent AND i.inhrelid =
'16410' AND c.relkind != 'p' ORDER BY inhseqno;
**************************

********* QUERY **********
SELECT c.oid::pg_catalog.regclass,
pg_catalog.pg_get_expr(c.relpartbound, c.oid) FROM pg_catalog.pg_class
c, pg_catalog.pg_inherits i WHERE c.oid=i.inhrelid AND i.inhparent =
'16410' ORDER BY c.oid::pg_catalog.regclass::pg_catalog.text;
**************************

Table "public.foo"
Column | Type | Collation | Nullable | Default
--------+---------+-----------+----------+---------
id | integer | | |
Policies (forced row security enabled):
POLICY "p1"
USING ((id <> 42))

test=#
8<--------------------------

Hope this helps,

Joe

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