Generalize TRUNCATE to support truncating multiple tables in one

command.  This is useful because we can allow truncation of tables
referenced by foreign keys, so long as the referencing table is
truncated in the same command.

Alvaro Herrera

1 files changed, 15 insertions, 14 deletions

diff --git a/doc/src/sgml/ref/truncate.sgml b/doc/src/sgml/ref/truncate.sgml
index 8bd220f77a7..03ee825ad52 100644
--- a/doc/src/sgml/ref/truncate.sgml
+++ b/doc/src/sgml/ref/truncate.sgml
@@ -1,5 +1,5 @@
 <!--
-$PostgreSQL: pgsql/doc/src/sgml/ref/truncate.sgml,v 1.17 2004/03/23 13:21:41 neilc Exp $
+$PostgreSQL: pgsql/doc/src/sgml/ref/truncate.sgml,v 1.18 2005/01/27 03:17:08 tgl Exp $
 PostgreSQL documentation
 -->
 
@@ -11,7 +11,7 @@ PostgreSQL documentation
 
  <refnamediv>
   <refname>TRUNCATE</refname>
-  <refpurpose>empty a table</refpurpose>
+  <refpurpose>empty a table or set of tables</refpurpose>
  </refnamediv>
 
  <indexterm zone="sql-truncate">
@@ -20,7 +20,7 @@ PostgreSQL documentation
 
  <refsynopsisdiv>
 <synopsis>
-TRUNCATE [ TABLE ] <replaceable class="PARAMETER">name</replaceable>
+TRUNCATE [ TABLE ] <replaceable class="PARAMETER">name</replaceable> [, ...]
 </synopsis>
  </refsynopsisdiv>
 
@@ -28,10 +28,10 @@ TRUNCATE [ TABLE ] <replaceable class="PARAMETER">name</replaceable>
   <title>Description</title>
 
   <para>
-   <command>TRUNCATE</command> quickly removes all rows from a
-   table. It has the same effect as an unqualified
-   <command>DELETE</command> but since it does not actually scan the
-   table it is faster. This is most useful on large tables.
+   <command>TRUNCATE</command> quickly removes all rows from a set of
+   tables. It has the same effect as an unqualified
+   <command>DELETE</command> on each table, but since it does not actually
+   scan the tables it is faster. This is most useful on large tables.
   </para>
  </refsect1>
   
@@ -43,7 +43,7 @@ TRUNCATE [ TABLE ] <replaceable class="PARAMETER">name</replaceable>
     <term><replaceable class="PARAMETER">name</replaceable></term>
     <listitem>
      <para>
-      The name (optionally schema-qualified) of the table to be truncated.
+      The name (optionally schema-qualified) of a table to be truncated.
      </para>
     </listitem>
    </varlistentry>
@@ -54,14 +54,15 @@ TRUNCATE [ TABLE ] <replaceable class="PARAMETER">name</replaceable>
   <title>Notes</title>
 
   <para>
-   <command>TRUNCATE</> cannot be used if there are foreign-key references
-   to the table from other tables.  Checking validity in such cases would
-   require table scans, and the whole point is not to do one.
+   <command>TRUNCATE</> cannot be used on a table that has foreign-key
+   references from other tables, unless all such tables are also truncated
+   in the same command.  Checking validity in such cases would require table
+   scans, and the whole point is not to do one.
   </para>
 
   <para>
    <command>TRUNCATE</> will not run any user-defined <literal>ON
-   DELETE</literal> triggers that might exist for the table.
+   DELETE</literal> triggers that might exist for the tables.
   </para>
  </refsect1>
 
@@ -69,10 +70,10 @@ TRUNCATE [ TABLE ] <replaceable class="PARAMETER">name</replaceable>
   <title>Examples</title>
 
   <para>
-   Truncate the table <literal>bigtable</literal>:
+   Truncate the tables <literal>bigtable</literal> and <literal>fattable</literal>:
 
 <programlisting>
-TRUNCATE TABLE bigtable;
+TRUNCATE TABLE bigtable, fattable;
 </programlisting>
   </para>
  </refsect1>