Add support for NOT ENFORCED in CHECK constraints

This adds support for the NOT ENFORCED/ENFORCED flag for constraints,
with support for check constraints.

The plan is to eventually support this for foreign key constraints,
where it is typically more useful.

Note that CHECK constraints do not currently support ALTER operations,
so changing the enforceability of an existing constraint isn't
possible without dropping and recreating it.  This could be added
later.

Author: Amul Sul <amul.sul@enterprisedb.com>
Reviewed-by: Peter Eisentraut <peter@eisentraut.org>
Reviewed-by: jian he <jian.universality@gmail.com>
Tested-by: Triveni N <triveni.n@enterprisedb.com>
Discussion: https://www.postgresql.org/message-id/flat/CAAJ_b962c5AcYW9KUt_R_ER5qs3fUGbe4az-SP-vuwPS-w-AGA@mail.gmail.com

6 files changed, 9 insertions, 1 deletions

diff --git a/src/include/access/tupdesc.h b/src/include/access/tupdesc.h
index 504ce222500..ff27df9e9a6 100644
--- a/src/include/access/tupdesc.h
+++ b/src/include/access/tupdesc.h
@@ -29,6 +29,7 @@ typedef struct ConstrCheck
 {
 	char	   *ccname;
 	char	   *ccbin;			/* nodeToString representation of expr */
+	bool		ccenforced;
 	bool		ccvalid;
 	bool		ccnoinherit;	/* this is a non-inheritable constraint */
 } ConstrCheck;
diff --git a/src/include/catalog/catversion.h b/src/include/catalog/catversion.h
index 24212ba57fa..fa300eaa2d2 100644
--- a/src/include/catalog/catversion.h
+++ b/src/include/catalog/catversion.h
@@ -57,6 +57,6 @@
  */
 
 /*							yyyymmddN */
-#define CATALOG_VERSION_NO	202412201
+#define CATALOG_VERSION_NO	202501101
 
 #endif
diff --git a/src/include/catalog/heap.h b/src/include/catalog/heap.h
index 9dea49c52b4..cad830dc39c 100644
--- a/src/include/catalog/heap.h
+++ b/src/include/catalog/heap.h
@@ -40,6 +40,7 @@ typedef struct CookedConstraint
 	char	   *name;			/* name, or NULL if none */
 	AttrNumber	attnum;			/* which attr (only for NOTNULL, DEFAULT) */
 	Node	   *expr;			/* transformed default or check expr */
+	bool		is_enforced;	/* is enforced? (only for CHECK) */
 	bool		skip_validation;	/* skip validation? (only for CHECK) */
 	bool		is_local;		/* constraint has local (non-inherited) def */
 	int16		inhcount;		/* number of times constraint is inherited */
diff --git a/src/include/catalog/pg_constraint.h b/src/include/catalog/pg_constraint.h
index ba35d481db3..ccc047e5e7a 100644
--- a/src/include/catalog/pg_constraint.h
+++ b/src/include/catalog/pg_constraint.h
@@ -51,6 +51,7 @@ CATALOG(pg_constraint,2606,ConstraintRelationId)
 	char		contype;		/* constraint type; see codes below */
 	bool		condeferrable;	/* deferrable constraint? */
 	bool		condeferred;	/* deferred by default? */
+	bool		conenforced;	/* enforced constraint? */
 	bool		convalidated;	/* constraint has been validated? */
 
 	/*
@@ -222,6 +223,7 @@ extern Oid	CreateConstraintEntry(const char *constraintName,
 								  char constraintType,
 								  bool isDeferrable,
 								  bool isDeferred,
+								  bool isEnforced,
 								  bool isValidated,
 								  Oid parentConstrId,
 								  Oid relId,
diff --git a/src/include/nodes/parsenodes.h b/src/include/nodes/parsenodes.h
index 38d6ad7dcbd..b191eaaecab 100644
--- a/src/include/nodes/parsenodes.h
+++ b/src/include/nodes/parsenodes.h
@@ -2736,6 +2736,8 @@ typedef enum ConstrType			/* types of constraints */
 	CONSTR_ATTR_NOT_DEFERRABLE,
 	CONSTR_ATTR_DEFERRED,
 	CONSTR_ATTR_IMMEDIATE,
+	CONSTR_ATTR_ENFORCED,
+	CONSTR_ATTR_NOT_ENFORCED,
 } ConstrType;
 
 /* Foreign key action codes */
@@ -2757,6 +2759,7 @@ typedef struct Constraint
 	char	   *conname;		/* Constraint name, or NULL if unnamed */
 	bool		deferrable;		/* DEFERRABLE? */
 	bool		initdeferred;	/* INITIALLY DEFERRED? */
+	bool		is_enforced;	/* enforced constraint? */
 	bool		skip_validation;	/* skip validation of existing rows? */
 	bool		initially_valid;	/* mark the new constraint as valid? */
 	bool		is_no_inherit;	/* is constraint non-inheritable? */
diff --git a/src/include/parser/kwlist.h b/src/include/parser/kwlist.h
index 24c22a8694b..cf2917ad07e 100644
--- a/src/include/parser/kwlist.h
+++ b/src/include/parser/kwlist.h
@@ -153,6 +153,7 @@ PG_KEYWORD("enable", ENABLE_P, UNRESERVED_KEYWORD, BARE_LABEL)
 PG_KEYWORD("encoding", ENCODING, UNRESERVED_KEYWORD, BARE_LABEL)
 PG_KEYWORD("encrypted", ENCRYPTED, UNRESERVED_KEYWORD, BARE_LABEL)
 PG_KEYWORD("end", END_P, RESERVED_KEYWORD, BARE_LABEL)
+PG_KEYWORD("enforced", ENFORCED, UNRESERVED_KEYWORD, BARE_LABEL)
 PG_KEYWORD("enum", ENUM_P, UNRESERVED_KEYWORD, BARE_LABEL)
 PG_KEYWORD("error", ERROR_P, UNRESERVED_KEYWORD, BARE_LABEL)
 PG_KEYWORD("escape", ESCAPE, UNRESERVED_KEYWORD, BARE_LABEL)