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-rw-r--r--doc/src/sgml/ref/alter_sequence.sgml11
-rw-r--r--doc/src/sgml/ref/truncate.sgml60
2 files changed, 59 insertions, 12 deletions
diff --git a/doc/src/sgml/ref/alter_sequence.sgml b/doc/src/sgml/ref/alter_sequence.sgml
index 3c982eee6f1..31e64dac35d 100644
--- a/doc/src/sgml/ref/alter_sequence.sgml
+++ b/doc/src/sgml/ref/alter_sequence.sgml
@@ -1,5 +1,5 @@
<!--
-$PostgreSQL: pgsql/doc/src/sgml/ref/alter_sequence.sgml,v 1.19 2007/10/25 18:54:03 tgl Exp $
+$PostgreSQL: pgsql/doc/src/sgml/ref/alter_sequence.sgml,v 1.20 2008/05/16 23:36:04 tgl Exp $
PostgreSQL documentation
-->
@@ -26,7 +26,7 @@ PostgreSQL documentation
<synopsis>
ALTER SEQUENCE <replaceable class="parameter">name</replaceable> [ INCREMENT [ BY ] <replaceable class="parameter">increment</replaceable> ]
[ MINVALUE <replaceable class="parameter">minvalue</replaceable> | NO MINVALUE ] [ MAXVALUE <replaceable class="parameter">maxvalue</replaceable> | NO MAXVALUE ]
- [ RESTART [ WITH ] <replaceable class="parameter">start</replaceable> ] [ CACHE <replaceable class="parameter">cache</replaceable> ] [ [ NO ] CYCLE ]
+ [ RESTART [ [ WITH ] <replaceable class="parameter">start</replaceable> ] ] [ CACHE <replaceable class="parameter">cache</replaceable> ] [ [ NO ] CYCLE ]
[ OWNED BY { <replaceable class="parameter">table</replaceable>.<replaceable class="parameter">column</replaceable> | NONE } ]
ALTER SEQUENCE <replaceable class="parameter">name</replaceable> RENAME TO <replaceable class="parameter">new_name</replaceable>
ALTER SEQUENCE <replaceable class="parameter">name</replaceable> SET SCHEMA <replaceable class="parameter">new_schema</replaceable>
@@ -112,12 +112,15 @@ ALTER SEQUENCE <replaceable class="parameter">name</replaceable> SET SCHEMA <rep
<term><replaceable class="parameter">start</replaceable></term>
<listitem>
<para>
- The optional clause <literal>RESTART WITH <replaceable
- class="parameter">start</replaceable></literal> changes the
+ The optional clause <literal>RESTART [ WITH <replaceable
+ class="parameter">start</replaceable> ]</literal> changes the
current value of the sequence. This is equivalent to calling the
<function>setval</> function with <literal>is_called</literal> =
<literal>false</>: the specified value will be returned by the
<emphasis>next</> call of <function>nextval</>.
+ Writing <literal>RESTART</> with no <replaceable
+ class="parameter">start</replaceable> value is equivalent to supplying
+ the start value used when the sequence was created.
</para>
</listitem>
</varlistentry>
diff --git a/doc/src/sgml/ref/truncate.sgml b/doc/src/sgml/ref/truncate.sgml
index 486a2d3e992..effe903b099 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 1.25 2008/03/28 00:21:55 tgl Exp $
+$PostgreSQL: pgsql/doc/src/sgml/ref/truncate.sgml,v 1.26 2008/05/16 23:36:04 tgl Exp $
PostgreSQL documentation
-->
@@ -20,7 +20,8 @@ PostgreSQL documentation
<refsynopsisdiv>
<synopsis>
-TRUNCATE [ TABLE ] <replaceable class="PARAMETER">name</replaceable> [, ...] [ CASCADE | RESTRICT ]
+TRUNCATE [ TABLE ] <replaceable class="PARAMETER">name</replaceable> [, ... ]
+ [ RESTART IDENTITY | CONTINUE IDENTITY ] [ CASCADE | RESTRICT ]
</synopsis>
</refsynopsisdiv>
@@ -51,6 +52,25 @@ TRUNCATE [ TABLE ] <replaceable class="PARAMETER">name</replaceable> [, ...] [ C
</varlistentry>
<varlistentry>
+ <term><literal>RESTART IDENTITY</literal></term>
+ <listitem>
+ <para>
+ Automatically restart sequences owned by columns of
+ the truncated table(s).
+ </para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term><literal>CONTINUE IDENTITY</literal></term>
+ <listitem>
+ <para>
+ Do not change the values of sequences. This is the default.
+ </para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
<term><literal>CASCADE</literal></term>
<listitem>
<para>
@@ -66,7 +86,7 @@ TRUNCATE [ TABLE ] <replaceable class="PARAMETER">name</replaceable> [, ...] [ C
<listitem>
<para>
Refuse to truncate if any of the tables have foreign-key references
- from tables that are not to be truncated. This is the default.
+ from tables that are not listed in the command. This is the default.
</para>
</listitem>
</varlistentry>
@@ -119,11 +139,23 @@ TRUNCATE [ TABLE ] <replaceable class="PARAMETER">name</replaceable> [, ...] [ C
cause visible inconsistency between the contents of the truncated
table and other tables in the database.
</para>
+ </warning>
+
+ <para>
+ <command>TRUNCATE</> is transaction-safe with respect to the data
+ in the tables: the truncation will be safely rolled back if the surrounding
+ transaction does not commit.
+ </para>
+ <warning>
<para>
- <command>TRUNCATE</> is transaction-safe, however: the truncation
- will be safely rolled back if the surrounding transaction does not
- commit.
+ Any <command>ALTER SEQUENCE RESTART</> operations performed as a
+ consequence of using the <literal>RESTART IDENTITY</> option are
+ nontransactional and will not be rolled back. To minimize risk,
+ these operations are performed only after all the rest of
+ <command>TRUNCATE</>'s work is done. In practice this will only
+ be an issue if <command>TRUNCATE</> is performed inside a
+ transaction block that is aborted afterwards.
</para>
</warning>
</refsect1>
@@ -132,7 +164,8 @@ TRUNCATE [ TABLE ] <replaceable class="PARAMETER">name</replaceable> [, ...] [ C
<title>Examples</title>
<para>
- Truncate the tables <literal>bigtable</literal> and <literal>fattable</literal>:
+ Truncate the tables <literal>bigtable</literal> and
+ <literal>fattable</literal>:
<programlisting>
TRUNCATE bigtable, fattable;
@@ -140,6 +173,14 @@ TRUNCATE bigtable, fattable;
</para>
<para>
+ The same, and also reset any associated sequence generators:
+
+<programlisting>
+TRUNCATE bigtable, fattable RESTART IDENTITY;
+</programlisting>
+ </para>
+
+ <para>
Truncate the table <literal>othertable</literal>, and cascade to any tables
that reference <literal>othertable</literal> via foreign-key
constraints:
@@ -154,7 +195,10 @@ TRUNCATE othertable CASCADE;
<title>Compatibility</title>
<para>
- There is no <command>TRUNCATE</command> command in the SQL standard.
+ The draft SQL:2008 standard includes a <command>TRUNCATE</command> command,
+ but at this writing it is uncertain whether that will reach standardization
+ or be fully compatible with <productname>PostgreSQL</productname>'s
+ implementation.
</para>
</refsect1>
</refentry>
generated by cgit v1.2.3 (git 2.46.0) at 2025-12-06 18:59:19 +0000