ALTER TABLE command to change generation expression
This adds a new ALTER TABLE subcommand ALTER COLUMN ... SET EXPRESSION
that changes the generation expression of a generated column.
The syntax is not standard but was adapted from other SQL
implementations.
This command causes a table rewrite, using the usual ALTER TABLE
mechanisms. The implementation is similar to and makes use of some of
the infrastructure of the SET DATA TYPE subcommand (for example,
rebuilding constraints and indexes afterwards). The new command
requires a new pass in AlterTablePass, and the ADD COLUMN pass had to
be moved earlier so that combinations of ADD COLUMN and SET EXPRESSION
can work.
Author: Amul Sul <sulamul@gmail.com>
Discussion:
https://www.postgresql.org/message-id/flat/CAAJ_b94yyJeGA-5M951_Lr+KfZokOp-2kXicpmEhi5FXhBeTog@mail.gmail.com
Branch
------
master
Details
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https://git.postgresql.org/pg/commitdiff/5d06e99a3cfc23bbc217b4d78b8c070ad52f720e
Modified Files
--------------
doc/src/sgml/ref/alter_table.sgml | 12 ++
src/backend/commands/tablecmds.c | 235 ++++++++++++++++-----
src/backend/parser/gram.y | 10 +
src/bin/psql/tab-complete.c | 10 +-
src/include/nodes/parsenodes.h | 1 +
.../modules/test_ddl_deparse/test_ddl_deparse.c | 3 +
src/test/regress/expected/generated.out | 217 ++++++++++++++++---
src/test/regress/sql/generated.sql | 52 ++++-
8 files changed, 460 insertions(+), 80 deletions(-)