pgsql: ALTER TABLE ... ALTER CONSTRAINT for FKs

ALTER TABLE ... ALTER CONSTRAINT for FKs

Allow constraint attributes to be altered,
so the default setting of NOT DEFERRABLE
can be altered to DEFERRABLE and back.

Review by Abhijit Menon-Sen

Branch
------
master

Details
-------
http://git.postgresql.org/pg/commitdiff/f177cbfe676dc2c7ca2b206c54d6bf819feeea8b

Modified Files
--------------
doc/src/sgml/ref/alter_table.sgml         |   11 +++
src/backend/commands/tablecmds.c          |  139 +++++++++++++++++++++++++++++
src/backend/parser/gram.y                 |   15 ++++
src/include/nodes/parsenodes.h            |    1 +
src/test/regress/expected/foreign_key.out |   19 ++++
src/test/regress/sql/foreign_key.sql      |   20 +++++
6 files changed, 205 insertions(+)