Remove not-really-standard implementation of CREATE TABLE's UNDER clause,

and revert documentation to describe the existing INHERITS clause
instead, per recent discussion in pghackers.  Also fix implementation
of SQL_inheritance SET variable: it is not cool to look at this var
during the initial parsing phase, only during parse_analyze().  See
recent bug report concerning misinterpretation of date constants just
after a SET TIMEZONE command.  gram.y really has to be an invariant
transformation of the query string to a raw parsetree; anything that
can vary with time must be done during parse analysis.

4 files changed, 70 insertions, 49 deletions

diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 0e1cf4df4d7..dcfe90eec3b 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -1,5 +1,5 @@
 <!--
-$Header: /cvsroot/pgsql/doc/src/sgml/advanced.sgml,v 1.19 2000/12/30 19:11:45 petere Exp $
+$Header: /cvsroot/pgsql/doc/src/sgml/advanced.sgml,v 1.20 2001/01/05 06:34:15 tgl Exp $
 -->
 
  <chapter id="advanced">
@@ -33,9 +33,9 @@ CREATE TABLE cities (
     altitude        int     -- (in ft)
 );
 
-CREATE TABLE capitals UNDER cities (
+CREATE TABLE capitals (
     state           char(2)
-);
+) INHERITS (cities);
     </programlisting>
 
     In this case, an  instance  of  capitals  <firstterm>inherits</firstterm>  all
@@ -64,12 +64,12 @@ CREATE TABLE capitals UNDER cities (
    <para>
     For example, the  following  query finds the  names  of  all  cities,
     including  state capitals, that are located at an altitude 
-    over 500ft, the query is:
+    over 500ft:
 
     <programlisting>
-SELECT c.name, c.altitude
-    FROM cities c
-    WHERE c.altitude > 500;
+SELECT name, altitude
+    FROM cities
+    WHERE altitude &gt; 500;
     </programlisting>
 
     which returns:
@@ -89,8 +89,8 @@ SELECT c.name, c.altitude
 
    <para>
     On the other hand, the  following  query  finds
-    all  the cities, but not capital cities 
-    that are situated at an attitude of 500ft or higher:
+    all  the cities that are not state capitals and
+    are situated at an altitude of 500ft or higher:
 
     <programlisting>
 SELECT name, altitude
@@ -109,7 +109,7 @@ SELECT name, altitude
 
    <para>
     Here the <quote>ONLY</quote> before cities indicates that the query should
-    be  run over only cities and not classes below cities in the
+    be  run over only the cities table, and not classes below cities in the
     inheritance hierarchy.  Many of the  commands  that  we
     have  already discussed -- <command>SELECT</command>,
     <command>UPDATE</command> and <command>DELETE</command> --
@@ -121,13 +121,18 @@ SELECT name, altitude
     <para>
      In previous versions of <productname>Postgres</productname>, the
      default was not to get access to child tables. This was found to
-     be error prone and is also in violation of SQL. Under the old
+     be error prone and is also in violation of SQL99. Under the old
      syntax, to get the sub-classes you append "*" to the table name.
      For example
 <programlisting>
 SELECT * from cities*;
 </programlisting>
-     To get the old behavior, the set configuration option
+     You can still explicitly specify scanning child tables by appending
+     "*", as well as explicitly specify not scanning child tables by
+     writing <quote>ONLY</quote>.  But beginning in version 7.1, the default
+     behavior for an undecorated table name is to scan its child tables
+     too, whereas before the default was not to do so.  To get the old
+     default behavior, set the configuration option
      <literal>SQL_Inheritance</literal> to off, e.g.,
 <programlisting>
 SET SQL_Inheritance TO OFF;
diff --git a/doc/src/sgml/inherit.sgml b/doc/src/sgml/inherit.sgml
index bb0a4d9c7a6..37cd94c5862 100644
--- a/doc/src/sgml/inherit.sgml
+++ b/doc/src/sgml/inherit.sgml
@@ -1,5 +1,5 @@
 <!--
-$Header: /cvsroot/pgsql/doc/src/sgml/Attic/inherit.sgml,v 1.11 2000/07/02 22:00:23 momjian Exp $
+$Header: /cvsroot/pgsql/doc/src/sgml/Attic/inherit.sgml,v 1.12 2001/01/05 06:34:15 tgl Exp $
 -->
 
  <chapter id="inherit">
@@ -17,9 +17,9 @@ CREATE TABLE cities (
     altitude        int     -- (in ft)
 );
 
-CREATE TABLE capitals UNDER cities (
+CREATE TABLE capitals (
     state           char(2)
-);
+) INHERITS (cities);
 </programlisting>
 
    In this case, an  instance  of  capitals  <firstterm>inherits</firstterm>  all
@@ -43,15 +43,15 @@ CREATE TABLE capitals UNDER cities (
   </para>
 
   <para>
-   For example, the  following  query finds the  names  of  all  cities,
-   including  state capitals, that are located at an altitude 
-   over 500ft, the query is:
+    For example, the  following  query finds the  names  of  all  cities,
+    including  state capitals, that are located at an altitude 
+    over 500ft:
 
-   <programlisting>
-    SELECT c.name, c.altitude
-    FROM cities c
-    WHERE c.altitude > 500;
-</programlisting>
+    <programlisting>
+SELECT name, altitude
+    FROM cities
+    WHERE altitude &gt; 500;
+    </programlisting>
 
    which returns:
 
@@ -69,12 +69,12 @@ CREATE TABLE capitals UNDER cities (
   </para>
 
   <para>
-   On the other hand, the  following  query  finds
-   all  the cities, but not capital cities 
-   that are situated at an attitude of 500ft or higher:
+    On the other hand, the  following  query  finds
+    all  the cities that are not state capitals and
+    are situated at an altitude of 500ft or higher:
 
    <programlisting>
-    SELECT name, altitude
+SELECT name, altitude
     FROM ONLY cities
     WHERE altitude &gt; 500;
 
@@ -106,7 +106,7 @@ CREATE TABLE capitals UNDER cities (
    <programlisting>
     SELECT c.tableoid, c.name, c.altitude
     FROM cities c
-    WHERE c.altitude > 500;
+    WHERE c.altitude &gt; 500;
    </programlisting>
 
    which returns:
@@ -128,7 +128,7 @@ CREATE TABLE capitals UNDER cities (
    <programlisting>
     SELECT p.relname, c.name, c.altitude
     FROM cities c, pg_class p
-    WHERE c.altitude > 500 and c.tableoid = p.oid;
+    WHERE c.altitude &gt; 500 and c.tableoid = p.oid;
    </programlisting>
 
    which returns:
@@ -150,20 +150,25 @@ CREATE TABLE capitals UNDER cities (
   <note>
    <title>Deprecated</title> 
    <para>
-    In previous versions of <productname>Postgres</productname>, the
-    default was not to get access to child tables. This was found to
-    be error prone and is also in violation of SQL. Under the old
-    syntax, to get the sub-classes you append "*" to the table name.
-    For example
+     In previous versions of <productname>Postgres</productname>, the
+     default was not to get access to child tables. This was found to
+     be error prone and is also in violation of SQL99. Under the old
+     syntax, to get the sub-classes you append "*" to the table name.
+     For example
 <programlisting>
 SELECT * from cities*;
 </programlisting>
-    To get the old behavior, the set configuration option
-    <literal>SQL_Inheritance</literal> to off, e.g.,
+     You can still explicitly specify scanning child tables by appending
+     "*", as well as explicitly specify not scanning child tables by
+     writing <quote>ONLY</quote>.  But beginning in version 7.1, the default
+     behavior for an undecorated table name is to scan its child tables
+     too, whereas before the default was not to do so.  To get the old
+     default behavior, set the configuration option
+     <literal>SQL_Inheritance</literal> to off, e.g.,
 <programlisting>
 SET SQL_Inheritance TO OFF;
 </programlisting>
-    or add a line in your <filename>postgresql.conf</filename> file.
+     or add a line in your <filename>postgresql.conf</filename> file.
    </para>
   </note>
  </chapter>
diff --git a/doc/src/sgml/ref/alter_table.sgml b/doc/src/sgml/ref/alter_table.sgml
index 110b5204cfb..24513344d74 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 1.17 2000/12/25 23:15:26 petere Exp $
+$Header: /cvsroot/pgsql/doc/src/sgml/ref/alter_table.sgml,v 1.18 2001/01/05 06:34:16 tgl Exp $
 Postgres documentation
 -->
 
@@ -23,10 +23,10 @@ Postgres documentation
    <date>1999-07-20</date>
   </refsynopsisdivinfo>
   <synopsis>
-ALTER TABLE [ ONLY ]<replaceable class="PARAMETER">table</replaceable> [ * ]
+ALTER TABLE [ ONLY ] <replaceable class="PARAMETER">table</replaceable> [ * ]
     ADD [ COLUMN ] <replaceable class="PARAMETER">column</replaceable> <replaceable
     class="PARAMETER">type</replaceable>
-ALTER TABLE [ ONLY ]<replaceable class="PARAMETER">table</replaceable> [ * ]
+ALTER TABLE [ ONLY ] <replaceable class="PARAMETER">table</replaceable> [ * ]
     ALTER [ COLUMN ] <replaceable class="PARAMETER">column</replaceable> { SET DEFAULT <replaceable
     class="PARAMETER">value</replaceable> | DROP DEFAULT }
 ALTER TABLE <replaceable class="PARAMETER">table</replaceable> [ * ]
diff --git a/doc/src/sgml/ref/create_table.sgml b/doc/src/sgml/ref/create_table.sgml
index f4ac83f1b0d..fc0d98be250 100644
--- a/doc/src/sgml/ref/create_table.sgml
+++ b/doc/src/sgml/ref/create_table.sgml
@@ -1,5 +1,5 @@
 <!--
-$Header: /cvsroot/pgsql/doc/src/sgml/ref/create_table.sgml,v 1.38 2000/12/30 19:00:11 petere Exp $
+$Header: /cvsroot/pgsql/doc/src/sgml/ref/create_table.sgml,v 1.39 2001/01/05 06:34:16 tgl Exp $
 Postgres documentation
 -->
 
@@ -20,12 +20,10 @@ Postgres documentation
  </refnamediv>
  <refsynopsisdiv>
   <refsynopsisdivinfo>
-   <date>2000-03-25</date>
+   <date>2001-01-04</date>
   </refsynopsisdivinfo>
   <synopsis>
-CREATE [ TEMPORARY | TEMP ] TABLE <replaceable class="PARAMETER">table</replaceable> 
-    [ UNDER <replaceable>inherited_table</replaceable> [, ...] ]
-    (
+CREATE [ TEMPORARY | TEMP ] TABLE <replaceable class="PARAMETER">table</replaceable> (
     <replaceable class="PARAMETER">column</replaceable> <replaceable class="PARAMETER">type</replaceable>
     [ NULL | NOT NULL ] [ UNIQUE ] [ DEFAULT <replaceable class="PARAMETER">value</replaceable> ]
     [<replaceable>column_constraint_clause</replaceable> | PRIMARY KEY } [ ... ] ]
@@ -33,7 +31,7 @@ CREATE [ TEMPORARY | TEMP ] TABLE <replaceable class="PARAMETER">table</replacea
     [, PRIMARY KEY ( <replaceable class="PARAMETER">column</replaceable> [, ...] ) ]
     [, CHECK ( <replaceable class="PARAMETER">condition</replaceable> ) ]
     [, <replaceable>table_constraint_clause</replaceable> ]
-    )
+    ) [ INHERITS ( <replaceable>inherited_table</replaceable> [, ...] ) ]
   </synopsis>
   
   <refsect2 id="R2-SQL-CREATETABLE-1">
@@ -132,10 +130,10 @@ CREATE [ TEMPORARY | TEMP ] TABLE <replaceable class="PARAMETER">table</replacea
      </varlistentry>
 
      <varlistentry>
-      <term>UNDER <replaceable class="PARAMETER">inherited_table</replaceable></term>
+      <term>INHERITS <replaceable class="PARAMETER">inherited_table</replaceable></term>
       <listitem>
        <para>
-	The optional UNDER clause specifies a collection of table
+	The optional INHERITS clause specifies a list of table
 	names from which this table automatically inherits all fields.
 	If any inherited field name appears more than once, 
 	<productname>Postgres</productname>
@@ -231,7 +229,7 @@ ERROR:  DEFAULT: type mismatched
   </para>
 
   <para>
-   The optional UNDER
+   The optional INHERITS
    clause specifies a collection of table names from which this table
    automatically inherits all fields.  If any inherited field name
    appears more than once, Postgres reports an error.  Postgres automatically
@@ -2154,6 +2152,19 @@ ALTER DOMAIN cities
      </synopsis>
     </para>
    </refsect3>
+
+   <refsect3 id="R3-SQL-INHERITANCE-1">
+    <title>
+     Inheritance
+    </title>
+    <para>
+     Multiple inheritance via the INHERITS clause is a
+     <productname>Postgres</productname> language extension.
+     SQL99 (but not SQL92) defines single inheritance using a different
+     syntax and different semantics.  SQL99-style inheritance is not yet
+     supported by <productname>Postgres</productname>.
+    </para>
+   </refsect3>
   </refsect2>
  </refsect1>
 </refentry>