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-rw-r--r--doc/src/sgml/datatype.sgml62
-rw-r--r--doc/src/sgml/ref/create_sequence.sgml6
2 files changed, 53 insertions, 15 deletions
diff --git a/doc/src/sgml/datatype.sgml b/doc/src/sgml/datatype.sgml
index 21fa569a016..7f16688f324 100644
--- a/doc/src/sgml/datatype.sgml
+++ b/doc/src/sgml/datatype.sgml
@@ -1,5 +1,5 @@
<!--
-$Header: /cvsroot/pgsql/doc/src/sgml/datatype.sgml,v 1.57 2001/08/07 22:41:49 petere Exp $
+$Header: /cvsroot/pgsql/doc/src/sgml/datatype.sgml,v 1.58 2001/08/16 20:38:53 tgl Exp $
-->
<chapter id="datatype">
@@ -199,11 +199,17 @@ $Header: /cvsroot/pgsql/doc/src/sgml/datatype.sgml,v 1.57 2001/08/07 22:41:49 pe
<row>
<entry><type>serial</type></entry>
- <entry></entry>
+ <entry><type>serial4</type></entry>
<entry>autoincrementing four-byte integer</entry>
</row>
<row>
+ <entry><type>serial8</type></entry>
+ <entry></entry>
+ <entry>autoincrementing eight-byte integer</entry>
+ </row>
+
+ <row>
<entry><type>text</type></entry>
<entry></entry>
<entry>variable-length character string</entry>
@@ -394,10 +400,17 @@ $Header: /cvsroot/pgsql/doc/src/sgml/datatype.sgml,v 1.57 2001/08/07 22:41:49 pe
</row>
<row>
- <entry>serial</entry>
+ <entry>serial4</entry>
<entry>4 bytes</entry>
<entry>Identifier or cross-reference</entry>
- <entry>0 to +2147483647</entry>
+ <entry>1 to 2147483647</entry>
+ </row>
+
+ <row>
+ <entry>serial8</entry>
+ <entry>8 bytes</entry>
+ <entry>Identifier or cross-reference</entry>
+ <entry>1 to 9223372036854775807</entry>
</row>
</tbody>
</tgroup>
@@ -413,17 +426,27 @@ $Header: /cvsroot/pgsql/doc/src/sgml/datatype.sgml,v 1.57 2001/08/07 22:41:49 pe
</para>
<para>
- The <type>bigint</type> type may not be available on all platforms since
- it relies on compiler support for eight-byte integers.
+ The <type>bigint</type> type may not function correctly on all platforms,
+ since it relies on compiler support for eight-byte integers. On a machine
+ without such support, <type>bigint</type> acts the same
+ as <type>integer</type> (but still takes up eight bytes of storage).
</para>
<sect2 id="datatype-serial">
- <title>The Serial Type</title>
+ <title>The Serial Types</title>
<indexterm zone="datatype-serial">
<primary>serial</primary>
</indexterm>
+ <indexterm zone="datatype-serial">
+ <primary>serial4</primary>
+ </indexterm>
+
+ <indexterm zone="datatype-serial">
+ <primary>serial8</primary>
+ </indexterm>
+
<indexterm>
<primary>auto-increment</primary>
<see>serial</see>
@@ -435,9 +458,9 @@ $Header: /cvsroot/pgsql/doc/src/sgml/datatype.sgml,v 1.57 2001/08/07 22:41:49 pe
</indexterm>
<para>
- The <type>serial</type> type is a special-case type constructed by
- <productname>Postgres</productname> from other existing components.
- It is typically used to create unique identifiers for table entries.
+ The <type>serial</type> datatypes are not truly types, but are a
+ notational convenience for setting up unique identifier columns
+ in tables.
In the current implementation, specifying
<programlisting>
@@ -449,10 +472,14 @@ CREATE TABLE <replaceable class="parameter">tablename</replaceable> (<replaceabl
<programlisting>
CREATE SEQUENCE <replaceable class="parameter">tablename</replaceable>_<replaceable class="parameter">colname</replaceable>_seq;
CREATE TABLE <replaceable class="parameter">tablename</replaceable>
- (<replaceable class="parameter">colname</replaceable> integer DEFAULT nextval('<replaceable class="parameter">tablename</replaceable>_<replaceable class="parameter">colname</replaceable>_seq');
-CREATE UNIQUE INDEX <replaceable class="parameter">tablename</replaceable>_<replaceable class="parameter">colname</replaceable>_key on <replaceable class="parameter">tablename</replaceable> (<replaceable class="parameter">colname</replaceable>);
+ (<replaceable class="parameter">colname</replaceable> integer DEFAULT nextval('<replaceable class="parameter">tablename</replaceable>_<replaceable class="parameter">colname</replaceable>_seq') UNIQUE NOT NULL;
</programlisting>
+ Thus, we have created an integer column and arranged for its default
+ values to be assigned from a sequence generator. UNIQUE and NOT NULL
+ constraints are applied to ensure that explicitly-inserted values
+ will never be duplicates, either.
+
<caution>
<para>
The implicit sequence created for the <type>serial</type> type will
@@ -460,7 +487,18 @@ CREATE UNIQUE INDEX <replaceable class="parameter">tablename</replaceable>_<repl
table is dropped.
</para>
</caution>
+ </para>
+ <para>
+ The type names <type>serial</type> and <type>serial4</type> are
+ equivalent: both create <type>integer</type> columns. The type
+ name <type>serial8</type> works just the same way, except that it
+ creates a <type>bigint</type> column. <type>serial8</type> should
+ be used if you anticipate use of more than 2^31 identifiers over
+ the lifetime of the table.
+ </para>
+
+ <para>
Implicit sequences supporting the <type>serial</type> are
not automatically dropped when a table containing a serial type
is dropped. So, the following commands executed in order will likely fail:
diff --git a/doc/src/sgml/ref/create_sequence.sgml b/doc/src/sgml/ref/create_sequence.sgml
index 5d5a59d28ab..4f7b8b296d7 100644
--- a/doc/src/sgml/ref/create_sequence.sgml
+++ b/doc/src/sgml/ref/create_sequence.sgml
@@ -1,5 +1,5 @@
<!--
-$Header: /cvsroot/pgsql/doc/src/sgml/ref/create_sequence.sgml,v 1.17 2001/06/30 22:01:17 petere Exp $
+$Header: /cvsroot/pgsql/doc/src/sgml/ref/create_sequence.sgml,v 1.18 2001/08/16 20:38:53 tgl Exp $
Postgres documentation
-->
@@ -79,7 +79,7 @@ CREATE [ TEMPORARY | TEMP ] SEQUENCE <replaceable class="parameter">seqname</rep
The optional clause <option>MINVALUE
<replaceable class="parameter">minvalue</replaceable></option>
determines the minimum value
- a sequence can generate. The defaults are 1 and -2147483647 for
+ a sequence can generate. The defaults are 1 and -2^63-1 for
ascending and descending sequences, respectively.
</para>
</listitem>
@@ -92,7 +92,7 @@ CREATE [ TEMPORARY | TEMP ] SEQUENCE <replaceable class="parameter">seqname</rep
The optional clause <option>MAXVALUE
<replaceable class="parameter">maxvalue</replaceable></option>
determines the maximum
- value for the sequence. The defaults are 2147483647 and -1 for
+ value for the sequence. The defaults are 2^63-1 and -1 for
ascending and descending sequences, respectively.
</para>
</listitem>
generated by cgit v1.2.3 (git 2.25.1) at 2025-05-31 14:27:34 +0000