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Michael Paquier ecfed4a122 Improve error handling of column references in expression transformation
Column references are not allowed in default expressions and partition
bound expressions, and are restricted as such once the transformation of
their expressions is done.  However, trying to use more complex column
references can lead to confusing error messages.  For example, trying to
use a two-field column reference name for default expressions and
partition bounds leads to "missing FROM-clause entry for table", which
makes no sense in their respective context.

In order to make the errors generated more useful, this commit adds more
verbose messages when transforming column references depending on the
context.  This has a little consequence though: for example an
expression using an aggregate with a column reference as argument would
cause an error to be generated for the column reference, while the
aggregate was the problem reported before this commit because column
references get transformed first.

The confusion exists for default expressions for a long time, and the
problem is new as of v12 for partition bounds.  Still per the lack of
complaints on the matter no backpatch is done.

The patch has been written by Amit Langote and me, and Tom Lane has
provided the improvement of the documentation for default expressions on
the CREATE TABLE page.

Author: Amit Langote, Michael Paquier
Reviewed-by: Tom Lane
Discussion: https://postgr.es/m/20190326020853.GM2558@paquier.xyz
2019-03-27 21:04:25 +09:00
config Reorder configure tests for accept() in Windows 2019-03-04 14:42:12 -05:00
contrib Switch some palloc/memset calls to palloc0 2019-03-27 12:02:50 +09:00
doc Improve error handling of column references in expression transformation 2019-03-27 21:04:25 +09:00
src Improve error handling of column references in expression transformation 2019-03-27 21:04:25 +09:00
.dir-locals.el Make Emacs perl-mode indent more like perltidy. 2019-01-13 11:32:31 -08:00
.gitattributes Remove contrib/tsearch2. 2017-02-13 11:06:11 -05:00
.gitignore Support for optimizing and emitting code in LLVM JIT provider. 2018-03-22 11:05:22 -07:00
COPYRIGHT Update copyright for 2019 2019-01-02 12:44:25 -05:00
GNUmakefile.in Process EXTRA_INSTALL serially, during the first temp-install. 2018-12-31 13:54:38 -08:00
HISTORY Change documentation references to PG website to use https: not http: 2017-05-20 21:50:47 -04:00
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aclocal.m4 Fix configure's AC_CHECK_DECLS tests to work correctly with clang. 2018-11-19 12:01:47 -05:00
configure Reorder configure tests for accept() in Windows 2019-03-04 14:42:12 -05:00
configure.in Fix PERMIT_DECLARATION_AFTER_STATEMENT initialization. 2019-02-16 13:12:28 -08:00

README

PostgreSQL Database Management System
=====================================

This directory contains the source code distribution of the PostgreSQL
database management system.

PostgreSQL is an advanced object-relational database management system
that supports an extended subset of the SQL standard, including
transactions, foreign keys, subqueries, triggers, user-defined types
and functions.  This distribution also contains C language bindings.

PostgreSQL has many language interfaces, many of which are listed here:

	https://www.postgresql.org/download

See the file INSTALL for instructions on how to build and install
PostgreSQL.  That file also lists supported operating systems and
hardware platforms and contains information regarding any other
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system.  Copyright and license information can be found in the
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distribution; it can be read as described in the installation
instructions.

The latest version of this software may be obtained at
https://www.postgresql.org/download/.  For more information look at our
web site located at https://www.postgresql.org/.