Commit b548cde1 authored by Tom Lane's avatar Tom Lane

Some more small improvements in response to 7.4 interactive docs comments.

parent 8afe005f
<!-- <!--
$PostgreSQL: pgsql/doc/src/sgml/ref/create_table_as.sgml,v 1.28 2005/01/05 14:22:39 petere Exp $ $PostgreSQL: pgsql/doc/src/sgml/ref/create_table_as.sgml,v 1.29 2005/01/09 05:57:45 tgl Exp $
PostgreSQL documentation PostgreSQL documentation
--> -->
...@@ -157,6 +157,20 @@ CREATE [ [ GLOBAL | LOCAL ] { TEMPORARY | TEMP } ] TABLE <replaceable>table_name ...@@ -157,6 +157,20 @@ CREATE [ [ GLOBAL | LOCAL ] { TEMPORARY | TEMP } ] TABLE <replaceable>table_name
</para> </para>
</refsect1> </refsect1>
<refsect1>
<title>Examples</title>
<para>
Create a new table <literal>films_recent</literal> consisting of only
recent entries from the table <literal>films</literal>:
<programlisting>
CREATE TABLE films_recent AS
SELECT * FROM films WHERE date_prod &gt;= '2002-01-01';
</programlisting>
</para>
</refsect1>
<refsect1> <refsect1>
<title>Compatibility</title> <title>Compatibility</title>
......
<!-- <!--
$PostgreSQL: pgsql/doc/src/sgml/ref/delete.sgml,v 1.21 2005/01/04 00:39:53 tgl Exp $ $PostgreSQL: pgsql/doc/src/sgml/ref/delete.sgml,v 1.22 2005/01/09 05:57:45 tgl Exp $
PostgreSQL documentation PostgreSQL documentation
--> -->
...@@ -100,6 +100,33 @@ DELETE <replaceable class="parameter">count</replaceable> ...@@ -100,6 +100,33 @@ DELETE <replaceable class="parameter">count</replaceable>
</para> </para>
</refsect1> </refsect1>
<refsect1>
<title>Notes</title>
<para>
<productname>PostgreSQL</productname> lets you reference columns of
other tables in the <literal>WHERE</> condition. For example, to
delete all films produced by a given producer, one might do
<programlisting>
DELETE FROM films
WHERE producer_id = producers.id AND producers.name = 'foo';
</programlisting>
What is essentially happening here is a join between <structname>films</>
and <structname>producers</>, with all successfully joined
<structname>films</> rows being marked for deletion.
This syntax is not standard. A more standard way to do it is
<programlisting>
DELETE FROM films
WHERE producer_id IN (SELECT id FROM producers WHERE name = 'foo');
</programlisting>
In some cases the join style is easier to write or faster to
execute than the sub-select style. One objection to the join style
is that there is no explicit list of what tables are being used,
which makes the style somewhat error-prone; also it cannot handle
self-joins.
</para>
</refsect1>
<refsect1> <refsect1>
<title>Examples</title> <title>Examples</title>
...@@ -122,7 +149,9 @@ DELETE FROM films; ...@@ -122,7 +149,9 @@ DELETE FROM films;
<title>Compatibility</title> <title>Compatibility</title>
<para> <para>
This command conforms to the SQL standard. This command conforms to the SQL standard, except that the ability to
reference other tables in the <literal>WHERE</> clause is a
<productname>PostgreSQL</productname> extension.
</para> </para>
</refsect1> </refsect1>
</refentry> </refentry>
......
<!-- <!--
$PostgreSQL: pgsql/doc/src/sgml/ref/drop_group.sgml,v 1.9 2005/01/04 00:39:53 tgl Exp $ $PostgreSQL: pgsql/doc/src/sgml/ref/drop_group.sgml,v 1.10 2005/01/09 05:57:45 tgl Exp $
PostgreSQL documentation PostgreSQL documentation
--> -->
...@@ -29,7 +29,7 @@ DROP GROUP <replaceable class="PARAMETER">name</replaceable> ...@@ -29,7 +29,7 @@ DROP GROUP <replaceable class="PARAMETER">name</replaceable>
<para> <para>
<command>DROP GROUP</command> removes the specified group. The <command>DROP GROUP</command> removes the specified group. The
users in the group are not deleted. users in the group are not removed.
</para> </para>
</refsect1> </refsect1>
......
<!-- <!--
$PostgreSQL: pgsql/doc/src/sgml/ref/insert.sgml,v 1.28 2005/01/04 00:39:53 tgl Exp $ $PostgreSQL: pgsql/doc/src/sgml/ref/insert.sgml,v 1.29 2005/01/09 05:57:45 tgl Exp $
PostgreSQL documentation PostgreSQL documentation
--> -->
...@@ -162,7 +162,7 @@ INSERT INTO films VALUES ...@@ -162,7 +162,7 @@ INSERT INTO films VALUES
</para> </para>
<para> <para>
In this second example, the <literal>len</literal> column is In this example, the <literal>len</literal> column is
omitted and therefore it will have the default value: omitted and therefore it will have the default value:
<programlisting> <programlisting>
...@@ -172,7 +172,7 @@ INSERT INTO films (code, title, did, date_prod, kind) ...@@ -172,7 +172,7 @@ INSERT INTO films (code, title, did, date_prod, kind)
</para> </para>
<para> <para>
The third example uses the <literal>DEFAULT</literal> clause for This example uses the <literal>DEFAULT</literal> clause for
the date columns rather than specifying a value: the date columns rather than specifying a value:
<programlisting> <programlisting>
...@@ -184,11 +184,20 @@ INSERT INTO films (code, title, did, date_prod, kind) ...@@ -184,11 +184,20 @@ INSERT INTO films (code, title, did, date_prod, kind)
</para> </para>
<para> <para>
This example inserts several rows into table To insert a row consisting entirely of default values:
<literal>films</literal> from table <literal>tmp</literal>:
<programlisting> <programlisting>
INSERT INTO films SELECT * FROM tmp; INSERT INTO films DEFAULT VALUES;
</programlisting>
</para>
<para>
This example inserts some rows into table
<literal>films</literal> from a table <literal>tmp_films</literal>
with the same column layout as <literal>films</literal>:
<programlisting>
INSERT INTO films SELECT * FROM tmp_films WHERE date_prod &lt; '2004-05-07';
</programlisting> </programlisting>
</para> </para>
......
<!-- <!--
$PostgreSQL: pgsql/doc/src/sgml/ref/select_into.sgml,v 1.32 2005/01/04 03:58:16 tgl Exp $ $PostgreSQL: pgsql/doc/src/sgml/ref/select_into.sgml,v 1.33 2005/01/09 05:57:45 tgl Exp $
PostgreSQL documentation PostgreSQL documentation
--> -->
...@@ -105,6 +105,19 @@ SELECT [ ALL | DISTINCT [ ON ( <replaceable class="PARAMETER">expression</replac ...@@ -105,6 +105,19 @@ SELECT [ ALL | DISTINCT [ ON ( <replaceable class="PARAMETER">expression</replac
</para> </para>
</refsect1> </refsect1>
<refsect1>
<title>Examples</title>
<para>
Create a new table <literal>films_recent</literal> consisting of only
recent entries from the table <literal>films</literal>:
<programlisting>
SELECT * INTO films_recent FROM films WHERE date_prod &gt;= '2002-01-01';
</programlisting>
</para>
</refsect1>
<refsect1> <refsect1>
<title>Compatibility</title> <title>Compatibility</title>
...@@ -120,6 +133,14 @@ SELECT [ ALL | DISTINCT [ ON ( <replaceable class="PARAMETER">expression</replac ...@@ -120,6 +133,14 @@ SELECT [ ALL | DISTINCT [ ON ( <replaceable class="PARAMETER">expression</replac
new code. new code.
</para> </para>
</refsect1> </refsect1>
<refsect1>
<title>See Also</title>
<simplelist type="inline">
<member><xref linkend="sql-createtableas" endterm="sql-createtableas-title"></member>
</simplelist>
</refsect1>
</refentry> </refentry>
<!-- Keep this comment at the end of the file <!-- Keep this comment at the end of the file
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<!-- <!--
$PostgreSQL: pgsql/doc/src/sgml/ref/update.sgml,v 1.31 2005/01/04 03:58:16 tgl Exp $ $PostgreSQL: pgsql/doc/src/sgml/ref/update.sgml,v 1.32 2005/01/09 05:57:45 tgl Exp $
PostgreSQL documentation PostgreSQL documentation
--> -->
...@@ -114,8 +114,9 @@ UPDATE [ ONLY ] <replaceable class="PARAMETER">table</replaceable> SET <replacea ...@@ -114,8 +114,9 @@ UPDATE [ ONLY ] <replaceable class="PARAMETER">table</replaceable> SET <replacea
expressions. This is similar to the list of tables that can be expressions. This is similar to the list of tables that can be
specified in the <xref linkend="sql-from" specified in the <xref linkend="sql-from"
endterm="sql-from-title"> of a <command>SELECT</command> endterm="sql-from-title"> of a <command>SELECT</command>
statement; for example, an alias for the table name can be statement. Note that the target table must not appear in the
specified. <replaceable>fromlist</>, unless you intend a self-join (in which
case it must appear with an alias in the <replaceable>fromlist</>).
</para> </para>
</listitem> </listitem>
</varlistentry> </varlistentry>
...@@ -154,10 +155,13 @@ UPDATE <replaceable class="parameter">count</replaceable> ...@@ -154,10 +155,13 @@ UPDATE <replaceable class="parameter">count</replaceable>
<title>Notes</title> <title>Notes</title>
<para> <para>
When joining the target table to other tables using a <replaceable When a <literal>FROM</> clause is present, what essentially happens
class="PARAMETER">fromlist</replaceable>, be careful that the join is that the target table is joined to the tables mentioned in the
<replaceable>fromlist</replaceable>, and each output row of the join
represents an update operation for the target table. When using
<literal>FROM</> you should ensure that the join
produces at most one output row for each row to be modified. In produces at most one output row for each row to be modified. In
other words, a target row mustn't join to more than one row from other words, a target row shouldn't join to more than one row from
the other table(s). If it does, then only one of the join rows the other table(s). If it does, then only one of the join rows
will be used to update the target row, but which one will be used will be used to update the target row, but which one will be used
is not readily predictable. is not readily predictable.
...@@ -210,15 +214,18 @@ UPDATE employees SET sales_count = sales_count + 1 WHERE id = ...@@ -210,15 +214,18 @@ UPDATE employees SET sales_count = sales_count + 1 WHERE id =
</programlisting> </programlisting>
Attempt to insert a new stock item along with the quantity of stock. If Attempt to insert a new stock item along with the quantity of stock. If
the item exists, update the stock count of the existing item. To do this, the item already exists, instead update the stock count of the existing
use savepoints. item. To do this without failing the entire transaction, use savepoints.
<programlisting> <programlisting>
BEGIN; BEGIN;
-- other operations
SAVEPOINT sp1; SAVEPOINT sp1;
INSERT INTO wines VALUES('Chateau Lafite 2003', '24'); INSERT INTO wines VALUES('Chateau Lafite 2003', '24');
-- Check for unique violation on name -- Assume the above fails because of a unique key violation,
-- so now we issue these commands:
ROLLBACK TO sp1; ROLLBACK TO sp1;
UPDATE wines SET stock = stock + 24 WHERE winename='Chateau Lafite 2003'; UPDATE wines SET stock = stock + 24 WHERE winename = 'Chateau Lafite 2003';
-- continue with other operations, and eventually
COMMIT; COMMIT;
</programlisting> </programlisting>
</para> </para>
...@@ -228,10 +235,18 @@ COMMIT; ...@@ -228,10 +235,18 @@ COMMIT;
<title>Compatibility</title> <title>Compatibility</title>
<para> <para>
This command conforms to the <acronym>SQL</acronym> standard. The This command conforms to the <acronym>SQL</acronym> standard, except
<literal>FROM</literal> clause is a that the <literal>FROM</literal> clause is a
<productname>PostgreSQL</productname> extension. <productname>PostgreSQL</productname> extension.
</para> </para>
<para>
Some other database systems offer a <literal>FROM</> option in which
the target table is supposed to be listed again within <literal>FROM</>.
That is not how <productname>PostgreSQL</productname> interprets
<literal>FROM</>. Be careful when porting applications that use this
extension.
</para>
</refsect1> </refsect1>
</refentry> </refentry>
......
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