From 093905fb9bddd073b93128893ecceae5da6801d5 Mon Sep 17 00:00:00 2001
From: Peter Eisentraut <peter@eisentraut.org>
Date: Wed, 29 Mar 2023 16:42:37 +0200
Subject: [PATCH 2/2] Update information schema for catalogued not-null
 constraints

---
 src/backend/catalog/information_schema.sql | 57 ++--------------------
 1 file changed, 5 insertions(+), 52 deletions(-)

diff --git a/src/backend/catalog/information_schema.sql b/src/backend/catalog/information_schema.sql
index 0555e9bc03..414fd0c6ba 100644
--- a/src/backend/catalog/information_schema.sql
+++ b/src/backend/catalog/information_schema.sql
@@ -435,31 +435,15 @@ CREATE VIEW check_constraints AS
     SELECT CAST(current_database() AS sql_identifier) AS constraint_catalog,
            CAST(rs.nspname AS sql_identifier) AS constraint_schema,
            CAST(con.conname AS sql_identifier) AS constraint_name,
-           CAST(substring(pg_get_constraintdef(con.oid) from 7) AS character_data)
+           CAST(CASE con.contype WHEN 'c' THEN left(substring(pg_get_constraintdef(con.oid) from 8), -1)
+                                 WHEN 'n' THEN substring(pg_get_constraintdef(con.oid) from 10) || ' IS NOT NULL' END AS character_data)
              AS check_clause
     FROM pg_constraint con
            LEFT OUTER JOIN pg_namespace rs ON (rs.oid = con.connamespace)
            LEFT OUTER JOIN pg_class c ON (c.oid = con.conrelid)
            LEFT OUTER JOIN pg_type t ON (t.oid = con.contypid)
     WHERE pg_has_role(coalesce(c.relowner, t.typowner), 'USAGE')
-      AND con.contype = 'c'
-
-    UNION
-    -- not-null constraints
-
-    SELECT CAST(current_database() AS sql_identifier) AS constraint_catalog,
-           CAST(n.nspname AS sql_identifier) AS constraint_schema,
-           CAST(CAST(n.oid AS text) || '_' || CAST(r.oid AS text) || '_' || CAST(a.attnum AS text) || '_not_null' AS sql_identifier) AS constraint_name, -- XXX
-           CAST(a.attname || ' IS NOT NULL' AS character_data)
-             AS check_clause
-    FROM pg_namespace n, pg_class r, pg_attribute a
-    WHERE n.oid = r.relnamespace
-      AND r.oid = a.attrelid
-      AND a.attnum > 0
-      AND NOT a.attisdropped
-      AND a.attnotnull
-      AND r.relkind IN ('r', 'p')
-      AND pg_has_role(r.relowner, 'USAGE');
+      AND con.contype IN ('c', 'n');
 
 GRANT SELECT ON check_constraints TO PUBLIC;
 
@@ -822,7 +806,7 @@ CREATE VIEW constraint_column_usage AS
             AND d.classid = 'pg_catalog.pg_constraint'::regclass
             AND d.objid = c.oid
             AND c.connamespace = nc.oid
-            AND c.contype = 'c'
+            AND c.contype IN ('c', 'n')
             AND r.relkind IN ('r', 'p')
             AND NOT a.attisdropped
 
@@ -1832,6 +1816,7 @@ CREATE VIEW table_constraints AS
            CAST(r.relname AS sql_identifier) AS table_name,
            CAST(
              CASE c.contype WHEN 'c' THEN 'CHECK'
+                            WHEN 'n' THEN 'CHECK'
                             WHEN 'f' THEN 'FOREIGN KEY'
                             WHEN 'p' THEN 'PRIMARY KEY'
                             WHEN 'u' THEN 'UNIQUE' END
@@ -1856,38 +1841,6 @@ CREATE VIEW table_constraints AS
           AND c.contype NOT IN ('t', 'x')  -- ignore nonstandard constraints
           AND r.relkind IN ('r', 'p')
           AND (NOT pg_is_other_temp_schema(nr.oid))
-          AND (pg_has_role(r.relowner, 'USAGE')
-               -- SELECT privilege omitted, per SQL standard
-               OR has_table_privilege(r.oid, 'INSERT, UPDATE, DELETE, TRUNCATE, REFERENCES, TRIGGER')
-               OR has_any_column_privilege(r.oid, 'INSERT, UPDATE, REFERENCES') )
-
-    UNION ALL
-
-    -- not-null constraints
-
-    SELECT CAST(current_database() AS sql_identifier) AS constraint_catalog,
-           CAST(nr.nspname AS sql_identifier) AS constraint_schema,
-           CAST(CAST(nr.oid AS text) || '_' || CAST(r.oid AS text) || '_' || CAST(a.attnum AS text) || '_not_null' AS sql_identifier) AS constraint_name, -- XXX
-           CAST(current_database() AS sql_identifier) AS table_catalog,
-           CAST(nr.nspname AS sql_identifier) AS table_schema,
-           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('YES' AS yes_or_no) AS enforced,
-           CAST(NULL AS yes_or_no) AS nulls_distinct
-
-    FROM pg_namespace nr,
-         pg_class r,
-         pg_attribute a
-
-    WHERE nr.oid = r.relnamespace
-          AND r.oid = a.attrelid
-          AND a.attnotnull
-          AND a.attnum > 0
-          AND NOT a.attisdropped
-          AND r.relkind IN ('r', 'p')
-          AND (NOT pg_is_other_temp_schema(nr.oid))
           AND (pg_has_role(r.relowner, 'USAGE')
                -- SELECT privilege omitted, per SQL standard
                OR has_table_privilege(r.oid, 'INSERT, UPDATE, DELETE, TRUNCATE, REFERENCES, TRIGGER')
-- 
2.40.0