On 5/10/2017 7:45 PM, Igor Korot wrote:
I found this:https://wiki.postgresql.org/wiki/Retrieve_primary_key_columns,
but now I need
to connect this with information_schema.columns.

What is best way to do it?

Or maybe that query I referenced is completely wrong?


if you're using pg_catalog stuff there's little point in using the information_schema views, which exist for compatability with the SQL standard.

information_schema.columns is a view, like...

View definition:
SELECT current_database()::information_schema.sql_identifier AS table_catalog,
    nc.nspname::information_schema.sql_identifier AS table_schema,
    c.relname::information_schema.sql_identifier AS table_name,
    a.attname::information_schema.sql_identifier AS column_name,
    a.attnum::information_schema.cardinal_number AS ordinal_position,
pg_get_expr(ad.adbin, ad.adrelid)::information_schema.character_data AS column_default,
        CASE
WHEN a.attnotnull OR t.typtype = 'd'::"char" AND t.typnotnull THEN 'NO'::text
            ELSE 'YES'::text
        END::information_schema.yes_or_no AS is_nullable,
        CASE
            WHEN t.typtype = 'd'::"char" THEN
            CASE
WHEN bt.typelem <> 0::oid AND bt.typlen = (-1) THEN 'ARRAY'::text WHEN nbt.nspname = 'pg_catalog'::name THEN format_type(t.typbasetype, NULL::integer)
                ELSE 'USER-DEFINED'::text
            END
            ELSE
            CASE
WHEN t.typelem <> 0::oid AND t.typlen = (-1) THEN 'ARRAY'::text WHEN nt.nspname = 'pg_catalog'::name THEN format_type(a.atttypid, NULL::integer)
                ELSE 'USER-DEFINED'::text
            END
        END::information_schema.character_data AS data_type,
information_schema._pg_char_max_length(information_schema._pg_truetypid(a.*, t.*), information_schema._pg_truetypmod(a.*, t.*))::information_schema.cardinal_numb
er AS character_maximum_length,
information_schema._pg_char_octet_length(information_schema._pg_truetypid(a.*, t.*), information_schema._pg_truetypmod(a.*, t.*))::information_schema.cardinal_nu
mber AS character_octet_length,
information_schema._pg_numeric_precision(information_schema._pg_truetypid(a.*, t.*), information_schema._pg_truetypmod(a.*, t.*))::information_schema.cardinal_nu
mber AS numeric_precision,
information_schema._pg_numeric_precision_radix(information_schema._pg_truetypid(a.*, t.*), information_schema._pg_truetypmod(a.*, t.*))::information_schema.cardi
nal_number AS numeric_precision_radix,
information_schema._pg_numeric_scale(information_schema._pg_truetypid(a.*, t.*), information_schema._pg_truetypmod(a.*, t.*))::information_schema.cardinal_number
 AS numeric_scale,
information_schema._pg_datetime_precision(information_schema._pg_truetypid(a.*, t.*), information_schema._pg_truetypmod(a.*, t.*))::information_schema.cardinal_n
umber AS datetime_precision,
information_schema._pg_interval_type(information_schema._pg_truetypid(a.*, t.*), information_schema._pg_truetypmod(a.*, t.*))::information_schema.character_data
AS interval_type,
NULL::integer::information_schema.cardinal_number AS interval_precision, NULL::character varying::information_schema.sql_identifier AS character_set_catalog, NULL::character varying::information_schema.sql_identifier AS character_set_schema, NULL::character varying::information_schema.sql_identifier AS character_set_name,
        CASE
            WHEN nco.nspname IS NOT NULL THEN current_database()
            ELSE NULL::name
        END::information_schema.sql_identifier AS collation_catalog,
    nco.nspname::information_schema.sql_identifier AS collation_schema,
    co.collname::information_schema.sql_identifier AS collation_name,
        CASE
            WHEN t.typtype = 'd'::"char" THEN current_database()
            ELSE NULL::name
        END::information_schema.sql_identifier AS domain_catalog,
        CASE
            WHEN t.typtype = 'd'::"char" THEN nt.nspname
            ELSE NULL::name
        END::information_schema.sql_identifier AS domain_schema,
        CASE
            WHEN t.typtype = 'd'::"char" THEN t.typname
            ELSE NULL::name
        END::information_schema.sql_identifier AS domain_name,
    current_database()::information_schema.sql_identifier AS udt_catalog,
COALESCE(nbt.nspname, nt.nspname)::information_schema.sql_identifier AS udt_schema, COALESCE(bt.typname, t.typname)::information_schema.sql_identifier AS udt_name, NULL::character varying::information_schema.sql_identifier AS scope_catalog, NULL::character varying::information_schema.sql_identifier AS scope_schema, NULL::character varying::information_schema.sql_identifier AS scope_name, NULL::integer::information_schema.cardinal_number AS maximum_cardinality,
    a.attnum::information_schema.sql_identifier AS dtd_identifier,
'NO'::character varying::information_schema.yes_or_no AS is_self_referencing,
    'NO'::character varying::information_schema.yes_or_no AS is_identity,
NULL::character varying::information_schema.character_data AS identity_generation, NULL::character varying::information_schema.character_data AS identity_start, NULL::character varying::information_schema.character_data AS identity_increment, NULL::character varying::information_schema.character_data AS identity_maximum, NULL::character varying::information_schema.character_data AS identity_minimum, NULL::character varying::information_schema.yes_or_no AS identity_cycle, 'NEVER'::character varying::information_schema.character_data AS is_generated, NULL::character varying::information_schema.character_data AS generation_expression,
        CASE
WHEN c.relkind = 'r'::"char" OR (c.relkind = ANY (ARRAY['v'::"char", 'f'::"char"])) AND pg_column_is_updatable(c.oid::regclass, a.attnum, false) THEN 'YE
S'::text
            ELSE 'NO'::text
        END::information_schema.yes_or_no AS is_updatable
   FROM pg_attribute a
LEFT JOIN pg_attrdef ad ON a.attrelid = ad.adrelid AND a.attnum = ad.adnum
     JOIN (pg_class c
     JOIN pg_namespace nc ON c.relnamespace = nc.oid) ON a.attrelid = c.oid
     JOIN (pg_type t
     JOIN pg_namespace nt ON t.typnamespace = nt.oid) ON a.atttypid = t.oid
     LEFT JOIN (pg_type bt
JOIN pg_namespace nbt ON bt.typnamespace = nbt.oid) ON t.typtype = 'd'::"char" AND t.typbasetype = bt.oid
     LEFT JOIN (pg_collation co
JOIN pg_namespace nco ON co.collnamespace = nco.oid) ON a.attcollation = co.oid AND (nco.nspname <> 'pg_catalog'::name OR co.collname <> 'default'::name) WHERE NOT pg_is_other_temp_schema(nc.oid) AND a.attnum > 0 AND NOT a.attisdropped AND (c.relkind = ANY (ARRAY['r'::"char", 'v'::"char", 'f'::"char"])) AND (pg_has_ role(c.relowner, 'USAGE'::text) OR has_column_privilege(c.oid, a.attnum, 'SELECT, INSERT, UPDATE, REFERENCES'::text));



--
john r pierce, recycling bits in santa cruz



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