[CF 5285] v21 - NOT ENFORCED constraint feature

This branch was automatically generated by a robot using patches from an
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https://commitfest.postgresql.org/patch/5285

The branch will be overwritten each time a new patch version is posted to
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on the master branch.

Patch(es): https://www.postgresql.org/message-id/CAAJ_b94B8PByv_b4oxhHDzbGzjoY8cptKGAu-GX0_eiOkqEhHQ@mail.gmail.com
Author(s): Amul Sul

Author: Commitfest Bot

doc/src/sgml/catalogs.sgml

@@ -2620,7 +2620,7 @@ SCRAM-SHA-256$<replaceable>&lt;iteration count&gt;</replaceable>:<replaceable>&l
       </para>
       <para>
        Is the constraint enforced?
-       Currently, can be false only for CHECK constraints
+       Currently, can be false only for foreign keys and CHECK constraints
       </para></entry>
      </row>
 

doc/src/sgml/ref/alter_table.sgml

@@ -58,7 +58,7 @@ ALTER TABLE [ IF EXISTS ] <replaceable class="parameter">name</replaceable>
     ALTER [ COLUMN ] <replaceable class="parameter">column_name</replaceable> SET COMPRESSION <replaceable class="parameter">compression_method</replaceable>
     ADD <replaceable class="parameter">table_constraint</replaceable> [ NOT VALID ]
     ADD <replaceable class="parameter">table_constraint_using_index</replaceable>
-    ALTER CONSTRAINT <replaceable class="parameter">constraint_name</replaceable> [ DEFERRABLE | NOT DEFERRABLE ] [ INITIALLY DEFERRED | INITIALLY IMMEDIATE ]
+    ALTER CONSTRAINT <replaceable class="parameter">constraint_name</replaceable> [ DEFERRABLE | NOT DEFERRABLE ] [ INITIALLY DEFERRED | INITIALLY IMMEDIATE ] [ ENFORCED | NOT ENFORCED ]
     ALTER CONSTRAINT <replaceable class="parameter">constraint_name</replaceable> [ INHERIT | NO INHERIT ]
     VALIDATE CONSTRAINT <replaceable class="parameter">constraint_name</replaceable>
     DROP CONSTRAINT [ IF EXISTS ]  <replaceable class="parameter">constraint_name</replaceable> [ RESTRICT | CASCADE ]
@@ -589,7 +589,8 @@ WITH ( MODULUS <replaceable class="parameter">numeric_literal</replaceable>, REM
       This form validates a foreign key or check constraint that was
       previously created as <literal>NOT VALID</literal>, by scanning the
       table to ensure there are no rows for which the constraint is not
-      satisfied.  Nothing happens if the constraint is already marked valid.
+      satisfied.  If the constraint is not enforced, an error is thrown.
+      Nothing happens if the constraint is already marked valid.
       (See <xref linkend="sql-altertable-notes"/> below for an explanation
       of the usefulness of this command.)
      </para>

doc/src/sgml/ref/create_table.sgml

@@ -1409,7 +1409,7 @@ WITH ( MODULUS <replaceable class="parameter">numeric_literal</replaceable>, REM
      </para>
 
      <para>
-      This is currently only supported for <literal>CHECK</literal>
+      This is currently only supported for foreign key and <literal>CHECK</literal>
       constraints.
      </para>
     </listitem>

src/backend/catalog/pg_constraint.c

@@ -100,8 +100,9 @@ CreateConstraintEntry(const char *constraintName,
 	ObjectAddresses *addrs_auto;
 	ObjectAddresses *addrs_normal;
 
-	/* Only CHECK constraint can be not enforced */
-	Assert(isEnforced || constraintType == CONSTRAINT_CHECK);
+	/* Only CHECK or FOREIGN KEY constraint can be not enforced */
+	Assert(isEnforced || constraintType == CONSTRAINT_CHECK ||
+		   constraintType == CONSTRAINT_FOREIGN);
 	/* NOT ENFORCED constraint must be NOT VALID */
 	Assert(isEnforced || !isValidated);
 

src/backend/catalog/sql_features.txt

@@ -281,7 +281,7 @@ F461	Named character sets			NO
 F471	Scalar subquery values			YES	
 F481	Expanded NULL predicate			YES	
 F491	Constraint management			YES	
-F492	Optional table constraint enforcement			NO	check constraints only
+F492	Optional table constraint enforcement			YES	except not-null constraints
 F501	Features and conformance views			YES	
 F501	Features and conformance views	01	SQL_FEATURES view	YES	
 F501	Features and conformance views	02	SQL_SIZING view	YES