From: Justin Pryzby <pryzby@telsasoft.com>
To: Nagaraj Raj <nagaraj.sf@yahoo.com>
Cc: pgsql-performance@lists.postgresql.org
Subject: Re: tables meta data collection
Date: Tue, 2 Mar 2021 22:20:23 -0600
Message-ID: <20210303042023.GF29832@telsasoft.com> (raw)
In-Reply-To: <591365510.2330079.1614734451782@mail.yahoo.com>
References: <591365510.2330079.1614734451782.ref@mail.yahoo.com>
<591365510.2330079.1614734451782@mail.yahoo.com>
On Wed, Mar 03, 2021 at 01:20:51AM +0000, Nagaraj Raj wrote:
> I was trying to collect table metadata with a description; the use case is that I need to show all columns of the tables whether it has the description or not.
> I tried the below query, but it only gives column details that have a description and ignore others if not.
Looks like you should join information_schema.columns *before*
pg_catalog.pg_description, otherwise the columns view has nothing to join to
unless the column has a description.
...or you could use FULL OUTER JOIN on the columns view.
> SELECT c.table_schema,c.table_name,c.column_name,case when c.domain_name is not null then c.domain_name when c.data_type='character varying' THEN 'character varying('||c.character_maximum_length||')' when c.data_type='character' THEN 'character('||c.character_maximum_length||')' when c.data_type='numeric' THEN 'numeric('||c.numeric_precision||','||c.numeric_scale||')' else c.data_typeend as data_type,c.is_nullable, (select 'Y' from information_schema.table_constraints tcojoin information_schema.key_column_usage kcu on kcu.constraint_name = tco.constraint_name and kcu.constraint_schema = tco.constraint_schema and kcu.constraint_schema = c.table_schema and kcu.table_name = c.table_name and kcu.column_name = c.column_namewhere tco.constraint_type = 'PRIMARY KEY' ) as is_in_PK,(select distinct 'Y' from information_schema.table_constraints tcojoin information_schema.key_column_usage kcu on kcu.constraint_name = tco.constraint_name and kcu.constraint_schema = tco.constraint_schema and kcu.constraint_schema = c.table_schema and kcu.table_name = c.table_name and kcu.column_name = c.column_namewhere tco.constraint_type = 'FOREIGN KEY' ) as is_in_FK,pgd.description
>
> FROM pg_catalog.pg_statio_all_tables as st Left outer join pg_catalog.pg_description pgd on (pgd.objoid=st.relid) left outer join information_schema.columns c on (pgd.objsubid=c.ordinal_position and c.table_schema=st.schemaname and c.table_name=st.relname)where c.table_name='test'order by c.table_schema,c.table_name,c.ordinal_position;
>
> expected formate is :
>
> | table_schema | table_name | column_name | data_type | is_nullable | is_in_pk | is_in_fk | description |
--
Justin Pryzby
System Administrator
Telsasoft
+1-952-707-8581
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To: pgsql-performance@postgresql.org
Cc: pryzby@telsasoft.com, nagaraj.sf@yahoo.com, pgsql-performance@lists.postgresql.org
Subject: Re: tables meta data collection
In-Reply-To: <20210303042023.GF29832@telsasoft.com>
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