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Update/correct inheritance examples.

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This commit is contained in:
Tom Lane 2002-04-13 17:17:29 +00:00
parent 6f2c0d47f8
commit 291c875f23
1 changed files with 24 additions and 37 deletions
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61
doc/src/sgml/inherit.sgml
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@ -1,5 +1,5 @@
<!--
$Header: /cvsroot/pgsql/doc/src/sgml/Attic/inherit.sgml,v 1.18 2002/01/07 02:29:12 petere Exp $
$Header: /cvsroot/pgsql/doc/src/sgml/Attic/inherit.sgml,v 1.19 2002/04/13 17:17:29 tgl Exp $
-->
<chapter id="inherit">
@ -56,35 +56,28 @@ SELECT name, altitude
which returns:
<programlisting>
+----------+----------+
|name | altitude |
+----------+----------+
|Las Vegas | 2174 |
+----------+----------+
|Mariposa | 1953 |
+----------+----------+
|Madison | 845 |
+----------+----------+
name | altitude
-----------+----------
Las Vegas | 2174
Mariposa | 1953
Madison | 845
</programlisting>
</para>
<para>
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:
are situated at an altitude over 500ft:
<programlisting>
SELECT name, altitude
FROM ONLY cities
WHERE altitude &gt; 500;
+----------+----------+
|name | altitude |
+----------+----------+
|Las Vegas | 2174 |
+----------+----------+
|Mariposa | 1953 |
+----------+----------+
name | altitude
-----------+----------
Las Vegas | 2174
Mariposa | 1953
</programlisting>
</para>
@ -112,18 +105,16 @@ SELECT name, altitude
which returns:
<programlisting>
+---------+----------+----------+
|tableoid |name | altitude |
+---------+----------+----------+
|37292 |Las Vegas | 2174 |
+---------+----------+----------+
|37280 |Mariposa | 1953 |
+---------+----------+----------+
|37280 |Madison | 845 |
+---------+----------+----------+
tableoid | name | altitude
----------+-----------+----------
139793 | Las Vegas | 2174
139793 | Mariposa | 1953
139798 | Madison | 845
</programlisting>
If you do a join with pg_class you can see the actual table name:
(If you try to reproduce this example, you will probably get different
numeric OIDs.) By doing a join with pg_class you can see the actual table
names:
<programlisting>
SELECT p.relname, c.name, c.altitude
@ -134,15 +125,11 @@ SELECT name, altitude
which returns:
<programlisting>
+---------+----------+----------+
|relname |name | altitude |
+---------+----------+----------+
|capitals |Las Vegas | 2174 |
+---------+----------+----------+
|cities |Mariposa | 1953 |
+---------+----------+----------+
|cities |Madison | 845 |
+---------+----------+----------+
relname | name | altitude
----------+-----------+----------
cities | Las Vegas | 2174
cities | Mariposa | 1953
capitals | Madison | 845
</programlisting>
</para>