Обсуждение: pgsql: Add support for ALTER TABLE IF EXISTS ... RENAME CONSTRAINT

Add support for ALTER TABLE IF EXISTS ... RENAME CONSTRAINT

Also add regression test.  Previously this was documented to work, but
didn't.

Branch
------
master

Details
-------
http://git.postgresql.org/pg/commitdiff/1d8198bb44e7e7e3e96d96942f642e9964111628

Modified Files
--------------
src/backend/commands/tablecmds.c          |    9 ++++++++-
src/backend/parser/gram.y                 |   11 +++++++++++
src/test/regress/expected/alter_table.out |    2 ++
src/test/regress/sql/alter_table.sql      |    1 +
4 files changed, 22 insertions(+), 1 deletion(-)