Add more information_schema columns

- table_constraints.enforced
- triggers.action_order
- triggers.action_reference_old_table
- triggers.action_reference_new_table
Reviewed-by: Michael Paquier <michael.paquier@gmail.com>

doc/src/sgml/information_schema.sgml

@@ -5317,6 +5317,13 @@ ORDER BY c.ordinal_position;
       <entry><type>yes_or_no</type></entry>
       <entry><literal>YES</literal> if the constraint is deferrable and initially deferred, <literal>NO</literal> if not</entry>
      </row>
+     <row>
+      <entry><literal>enforced</literal></entry>
+      <entry><type>yes_or_no</type></entry>
+      <entry>Applies to a feature not available in
+      <productname>PostgreSQL</productname> (currently always
+      <literal>YES</literal>)</entry>
+     </row>
     </tbody>
    </tgroup>
   </table>
@@ -5761,7 +5768,14 @@ ORDER BY c.ordinal_position;
      <row>
       <entry><literal>action_order</literal></entry>
       <entry><type>cardinal_number</type></entry>
-      <entry>Not yet implemented</entry>
+      <entry>
+       Firing order among triggers on the same table having the same
+       <literal>event_manipulation</literal>,
+       <literal>action_timing</literal>, and
+       <literal>action_orientation</literal>.  In
+       <productname>PostgreSQL</productname>, triggers are fired in name
+       order, so this column reflects that.
+      </entry>
      </row>
 
      <row>
@@ -5806,13 +5820,13 @@ ORDER BY c.ordinal_position;
      <row>
       <entry><literal>action_reference_old_table</literal></entry>
       <entry><type>sql_identifier</type></entry>
-      <entry>Applies to a feature not available in <productname>PostgreSQL</productname></entry>
+      <entry>Name of the <quote>old</quote> transition table, or null if none</entry>
      </row>
 
      <row>
       <entry><literal>action_reference_new_table</literal></entry>
       <entry><type>sql_identifier</type></entry>
-      <entry>Applies to a feature not available in <productname>PostgreSQL</productname></entry>
+      <entry>Name of the <quote>new</quote> transition table, or null if none</entry>
      </row>
 
      <row>

src/backend/catalog/information_schema.sql

@@ -1783,7 +1783,8 @@ CREATE VIEW table_constraints AS
            CAST(CASE WHEN c.condeferrable THEN 'YES' ELSE 'NO' END AS yes_or_no)
              AS is_deferrable,
            CAST(CASE WHEN c.condeferred THEN 'YES' ELSE 'NO' END AS yes_or_no)
-             AS initially_deferred
+             AS initially_deferred,
+           CAST('YES' AS yes_or_no) AS enforced
 
     FROM pg_namespace nc,
          pg_namespace nr,
@@ -1812,7 +1813,8 @@ CREATE VIEW table_constraints AS
            CAST(r.relname AS sql_identifier) AS table_name,
            CAST('CHECK' AS character_data) AS constraint_type,
            CAST('NO' AS yes_or_no) AS is_deferrable,
-           CAST('NO' AS yes_or_no) AS initially_deferred
+           CAST('NO' AS yes_or_no) AS initially_deferred,
+           CAST('YES' AS yes_or_no) AS enforced
 
     FROM pg_namespace nr,
          pg_class r,
@@ -2084,8 +2086,12 @@ CREATE VIEW triggers AS
            CAST(current_database() AS sql_identifier) AS event_object_catalog,
            CAST(n.nspname AS sql_identifier) AS event_object_schema,
            CAST(c.relname AS sql_identifier) AS event_object_table,
-           CAST(null AS cardinal_number) AS action_order,
-           -- XXX strange hacks follow
+           CAST(
+             -- To determine action order, partition by schema, table,
+             -- event_manipulation (INSERT/DELETE/UPDATE), ROW/STATEMENT (1),
+             -- BEFORE/AFTER (66), then order by trigger name
+             rank() OVER (PARTITION BY n.oid, c.oid, em.num, t.tgtype & 1, t.tgtype & 66 ORDER BY t.tgname)
+             AS cardinal_number) AS action_order,
            CAST(
              CASE WHEN pg_has_role(c.relowner, 'USAGE')
                THEN (regexp_match(pg_get_triggerdef(t.oid), E'.{35,} WHEN \\((.+)\\) EXECUTE PROCEDURE'))[1]
@@ -2103,8 +2109,8 @@ CREATE VIEW triggers AS
              -- hard-wired refs to TRIGGER_TYPE_BEFORE, TRIGGER_TYPE_INSTEAD
              CASE t.tgtype & 66 WHEN 2 THEN 'BEFORE' WHEN 64 THEN 'INSTEAD OF' ELSE 'AFTER' END
              AS character_data) AS action_timing,
-           CAST(null AS sql_identifier) AS action_reference_old_table,
-           CAST(null AS sql_identifier) AS action_reference_new_table,
+           CAST(tgoldtable AS sql_identifier) AS action_reference_old_table,
+           CAST(tgnewtable AS sql_identifier) AS action_reference_new_table,
            CAST(null AS sql_identifier) AS action_reference_old_row,
            CAST(null AS sql_identifier) AS action_reference_new_row,
            CAST(null AS time_stamp) AS created

src/test/regress/sql/triggers.sql

@@ -92,6 +92,11 @@ delete from pkeys where pkey1 = 40 and pkey2 = '4';
 update pkeys set pkey1 = 7, pkey2 = '70' where pkey1 = 50 and pkey2 = '5';
 update pkeys set pkey1 = 7, pkey2 = '70' where pkey1 = 10 and pkey2 = '1';
 
+SELECT trigger_name, event_manipulation, event_object_schema, event_object_table,
+       action_order, action_condition, action_orientation, action_timing,
+       action_reference_old_table, action_reference_new_table
+  FROM information_schema.triggers ORDER BY 1, 2;
+
 DROP TABLE pkeys;
 DROP TABLE fkeys;
 DROP TABLE fkeys2;
@@ -279,6 +284,10 @@ CREATE TRIGGER insert_when BEFORE INSERT ON main_table
 FOR EACH STATEMENT WHEN (true) EXECUTE PROCEDURE trigger_func('insert_when');
 CREATE TRIGGER delete_when AFTER DELETE ON main_table
 FOR EACH STATEMENT WHEN (true) EXECUTE PROCEDURE trigger_func('delete_when');
+SELECT trigger_name, event_manipulation, event_object_schema, event_object_table,
+       action_order, action_condition, action_orientation, action_timing,
+       action_reference_old_table, action_reference_new_table
+  FROM information_schema.triggers ORDER BY 1, 2;
 INSERT INTO main_table (a) VALUES (123), (456);
 COPY main_table FROM stdin;
 123	999
@@ -1472,6 +1481,11 @@ create trigger child3_delete_trig
   after delete on child3 referencing old table as old_table
   for each statement execute procedure dump_delete();
 
+SELECT trigger_name, event_manipulation, event_object_schema, event_object_table,
+       action_order, action_condition, action_orientation, action_timing,
+       action_reference_old_table, action_reference_new_table
+  FROM information_schema.triggers ORDER BY 1, 2;
+
 -- insert directly into children sees respective child-format tuples
 insert into child1 values ('AAA', 42);
 insert into child2 values ('BBB', 42);