pgsql: Add support for NOT ENFORCED in CHECK constraints

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

Branch
------
master

Details
-------
https://git.postgresql.org/pg/commitdiff/ca87c415e2fccf81cec6fd45698dde9fae0ab570

Modified Files
--------------
doc/src/sgml/catalogs.sgml | 10 +++
doc/src/sgml/information_schema.sgml | 4 +-
doc/src/sgml/ref/alter_table.sgml | 12 +--
doc/src/sgml/ref/create_foreign_table.sgml | 6 +-
doc/src/sgml/ref/create_table.sgml | 34 +++++++-
src/backend/access/common/tupdesc.c | 2 +
src/backend/catalog/heap.c | 55 ++++++++++---
src/backend/catalog/index.c | 1 +
src/backend/catalog/information_schema.sql | 2 +-
src/backend/catalog/pg_constraint.c | 9 ++
src/backend/catalog/sql_features.txt | 2 +-
src/backend/commands/tablecmds.c | 51 +++++++++++-
src/backend/commands/trigger.c | 1 +
src/backend/commands/typecmds.c | 17 ++++
src/backend/executor/execMain.c | 8 +-
src/backend/nodes/makefuncs.c | 1 +
src/backend/optimizer/util/plancat.c | 11 +++
src/backend/parser/gram.y | 104 +++++++++++++++++++-----
src/backend/parser/parse_utilcmd.c | 57 +++++++++++--
src/backend/utils/adt/ruleutils.c | 6 +-
src/backend/utils/cache/relcache.c | 1 +
src/include/access/tupdesc.h | 1 +
src/include/catalog/catversion.h | 2 +-
src/include/catalog/heap.h | 1 +
src/include/catalog/pg_constraint.h | 2 +
src/include/nodes/parsenodes.h | 3 +
src/include/parser/kwlist.h | 1 +
src/test/regress/expected/alter_table.out | 10 +++
src/test/regress/expected/constraints.out | 40 ++++++++-
src/test/regress/expected/create_table_like.out | 10 ++-
src/test/regress/expected/domain.out | 22 +++++
src/test/regress/expected/inherit.out | 94 +++++++++++++++++++--
src/test/regress/sql/alter_table.sql | 7 ++
src/test/regress/sql/constraints.sql | 22 ++++-
src/test/regress/sql/create_table_like.sql | 3 +-
src/test/regress/sql/domain.sql | 10 +++
src/test/regress/sql/inherit.sql | 47 ++++++++++-
37 files changed, 599 insertions(+), 70 deletions(-)