database/postgres
1
0
Fork 0
mirror of https://github.com/postgres/postgres.git synced 2025-06-20 15:22:23 +03:00
Code Activity

Sequences are now based on int8, not int4, arithmetic. SERIAL pseudo-type

Browse Source 
has an alias SERIAL4 and a sister SERIAL8.  SERIAL8 is just the same
except the created column is type int8 not int4.
initdb forced.  Note this also breaks any chance of pg_upgrade from 7.1,
unless we hack up pg_upgrade to drop and recreate sequences.  (Which is
not out of the question, but I don't wanna do it.)
This commit is contained in:
Tom Lane
2001-08-16 20:38:56 +00:00
parent bcb0ccf5be
commit d4f4b971a4
21 changed files with 254 additions and 182 deletions
Download Patch File Download Diff File Expand all files Collapse all files

62
doc/src/sgml/datatype.sgml
View File

@ -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">
@ -199,10 +199,16 @@ $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>
@ -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:

6
doc/src/sgml/ref/create_sequence.sgml
View File

@ -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>