From 93dca0d224539c6f563fb1cdd508f96dd64cc903 Mon Sep 17 00:00:00 2001
From: Tom Lane <tgl@sss.pgh.pa.us>
Date: Sat, 19 Oct 2002 22:51:45 +0000
Subject: [PATCH] Fix incomplete definition of ALTER TABLE ADD/DROP CONSTRAINT
syntax. Add some verbiage about recent tweaks to behavior of ADD and DROP
COLUMN when there are descendant tables.
---
doc/src/sgml/ref/alter_table.sgml | 30 +++++++++++++++++++++++-------
1 file changed, 23 insertions(+), 7 deletions(-)
diff --git a/doc/src/sgml/ref/alter_table.sgml b/doc/src/sgml/ref/alter_table.sgml
index 7326bbe01c1..eea25682eb0 100644
--- a/doc/src/sgml/ref/alter_table.sgml
+++ b/doc/src/sgml/ref/alter_table.sgml
@@ -1,5 +1,5 @@
<!--
-$Header: /cvsroot/pgsql/doc/src/sgml/ref/alter_table.sgml,v 1.50 2002/09/21 18:32:54 petere Exp $
+$Header: /cvsroot/pgsql/doc/src/sgml/ref/alter_table.sgml,v 1.51 2002/10/19 22:51:45 tgl Exp $
PostgreSQL documentation
-->
@@ -38,9 +38,9 @@ ALTER TABLE [ ONLY ] <replaceable class="PARAMETER">table</replaceable> [ * ]
class="PARAMETER">new_column</replaceable>
ALTER TABLE <replaceable class="PARAMETER">table</replaceable>
RENAME TO <replaceable class="PARAMETER">new_table</replaceable>
-ALTER TABLE <replaceable class="PARAMETER">table</replaceable>
- ADD <replaceable class="PARAMETER">table_constraint_definition</replaceable>
-ALTER TABLE [ ONLY ] <replaceable class="PARAMETER">table</replaceable>
+ALTER TABLE [ ONLY ] <replaceable class="PARAMETER">table</replaceable> [ * ]
+ ADD <replaceable class="PARAMETER">table_constraint</replaceable>
+ALTER TABLE [ ONLY ] <replaceable class="PARAMETER">table</replaceable> [ * ]
DROP CONSTRAINT <replaceable class="PARAMETER">constraint_name</replaceable> [ RESTRICT | CASCADE ]
ALTER TABLE <replaceable class="PARAMETER">table</replaceable>
OWNER TO <replaceable class="PARAMETER">new_owner</replaceable>
@@ -110,7 +110,7 @@ ALTER TABLE <replaceable class="PARAMETER">table</replaceable>
</varlistentry>
<varlistentry>
- <term><replaceable class="PARAMETER"> table_constraint_definition </replaceable></term>
+ <term><replaceable class="PARAMETER"> table_constraint </replaceable></term>
<listitem>
<para>
New table constraint for the table.
@@ -298,7 +298,7 @@ ALTER TABLE <replaceable class="PARAMETER">table</replaceable>
</varlistentry>
<varlistentry>
- <term>ADD <replaceable class="PARAMETER">table_constraint_definition</replaceable></term>
+ <term>ADD <replaceable class="PARAMETER">table_constraint</replaceable></term>
<listitem>
<para>
This form adds a new constraint to a table using the same syntax as
@@ -311,7 +311,7 @@ ALTER TABLE <replaceable class="PARAMETER">table</replaceable>
<term>DROP CONSTRAINT</term>
<listitem>
<para>
- This form drops constraints on a table (and its children).
+ This form drops constraints on a table.
Currently, constraints on tables are not required to have unique
names, so there may be more than one constraint matching the specified
name. All such constraints will be dropped.
@@ -376,6 +376,22 @@ VACUUM FULL table;
</programlisting>
</para>
+ <para>
+ If a table has any descendant tables, it is not permitted to ADD or
+ RENAME a column in the parent table without doing the same to the
+ descendants --- that is, ALTER TABLE ONLY will be rejected. This
+ ensures that the descendants always have columns matching the parent.
+ </para>
+
+ <para>
+ A recursive DROP COLUMN operation will remove a descendant table's column
+ only if the descendant does not inherit that column from any other
+ parents and never had an independent definition of the column.
+ A nonrecursive DROP COLUMN (i.e., ALTER TABLE ONLY ... DROP COLUMN)
+ never removes any descendant columns, but instead marks them as
+ independently defined rather than inherited.
+ </para>
+
<para>
Changing any part of the schema of a system
catalog is not permitted.
--
GitLab