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Try to clarify characteristics of the SERIAL type.

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Fix source indenting, which does not affect output.
Note: still need docs on NUMERIC and DECIMAL
 (and let's not talk about regression tests :()
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Thomas G. Lockhart 1999-08-06 13:43:42 +00:00
parent e1fad50a5d
commit 4f1766f1ea
1 changed files with 759 additions and 730 deletions
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doc/src/sgml/datatype.sgml
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@ -265,7 +265,8 @@
<para> <para>
Numeric types consist of two- and four-byte integers and four- and eight-byte Numeric types consist of two- and four-byte integers and four- and eight-byte
floating point numbers.</para> floating point numbers.
</para>
<para> <para>
<table tocentry="1"> <table tocentry="1">
@ -328,6 +329,14 @@ functions. Refer to <xref endterm="math-opers" linkend="math-opers">
and <xref endterm="math-funcs" linkend="math-funcs"> for more information. and <xref endterm="math-funcs" linkend="math-funcs"> for more information.
</para> </para>
<para>
The <type>int8</type> type may not be available on all platforms since
it relies on compiler support for this.
</para>
<sect2>
<title>The Serial Type</title>
<para> <para>
The <type>serial</type> type is a special-case type constructed by The <type>serial</type> type is a special-case type constructed by
<productname>Postgres</productname> from other existing components. <productname>Postgres</productname> from other existing components.
@ -350,8 +359,14 @@ CREATE UNIQUE INDEX <replaceable class="parameter">tablename</replaceable>_<repl
<caution> <caution>
<para> <para>
The implicit sequence created for the <type>serial</type> type will The implicit sequence created for the <type>serial</type> type will
<emphasis>not</emphasis> be automatically removed when the table is dropped. <emphasis>not</emphasis> be automatically removed when the
So, the following commands executed in order will likely fail: table is dropped.
</para>
</caution>
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:
<programlisting> <programlisting>
CREATE TABLE <replaceable class="parameter">tablename</replaceable> (<replaceable class="parameter">colname</replaceable> SERIAL); CREATE TABLE <replaceable class="parameter">tablename</replaceable> (<replaceable class="parameter">colname</replaceable> SERIAL);
@ -360,20 +375,23 @@ CREATE TABLE <replaceable class="parameter">tablename</replaceable> (<replaceabl
</programlisting> </programlisting>
The sequence will remain in the database until explicitly dropped using The sequence will remain in the database until explicitly dropped using
<command>DROP SEQUENCE</command>.</para> <command>DROP SEQUENCE</command>.
</caution>
</para>
<para>
The <type>int8</type> type may not be available on all platforms since
it relies on compiler support for this.
</para> </para>
</sect2>
</sect1> </sect1>
<sect1> <sect1>
<title>Monetary Type</title> <title>Monetary Type</title>
<note>
<title>Obsolete Type</title>
<para>
The <type>money</type> is now obsolete. Use <type>numeric</type>
or <type>decimal</type> instead.
</para>
</note>
<para> <para>
The <type>money</type> type supports US-style currency with The <type>money</type> type supports US-style currency with
fixed decimal point representation. fixed decimal point representation.
@ -815,13 +833,13 @@ There are several ways to affect the appearance of date/time types:
<itemizedlist spacing="compact" mark="bullet"> <itemizedlist spacing="compact" mark="bullet">
<listitem> <listitem>
<para> <para>
The PGDATESTYLE environment variable used by the backend directly The <envar>PGDATESTYLE</envar> environment variable used by the backend directly
on postmaster startup. on postmaster startup.
</para> </para>
</listitem> </listitem>
<listitem> <listitem>
<para> <para>
The PGDATESTYLE environment variable used by the frontend libpq The <envar>PGDATESTYLE</envar> environment variable used by the frontend libpq
on session startup. on session startup.
</para> </para>
</listitem> </listitem>
@ -834,7 +852,7 @@ on session startup.
</para> </para>
<para> <para>
For <productname>Postgres</productname> v6.4 (and earlier) For <productname>Postgres</productname> v6.5 (and earlier)
the default date/time style is the default date/time style is
"non-European traditional Postgres". "non-European traditional Postgres".
In future releases, the default may become "ISO" (compatible with ISO-8601), In future releases, the default may become "ISO" (compatible with ISO-8601),
@ -901,7 +919,8 @@ on session startup.
sets the time zone for the session. sets the time zone for the session.
</para> </para>
</listitem> </listitem>
</itemizedlist></para> </itemizedlist>
</para>
<para> <para>
If an invalid time zone is specified, If an invalid time zone is specified,
@ -1291,7 +1310,7 @@ on session startup.
</sect2> </sect2>
<sect2> <sect2>
<title>datetime</title> <title><type>datetime</type></title>
<para> <para>
General-use date and time is input using a wide range of General-use date and time is input using a wide range of
@ -1327,7 +1346,8 @@ Timezones are either three characters (e.g. "GMT" or "PST") or ISO-compatible
offsets to GMT (e.g. "-08" or "-08:00" when in Pacific Standard Time). offsets to GMT (e.g. "-08" or "-08:00" when in Pacific Standard Time).
Dates are stored internally in Greenwich Mean Time. Input and output routines Dates are stored internally in Greenwich Mean Time. Input and output routines
translate time to the local time zone of the server. translate time to the local time zone of the server.
</para></sect2> </para>
</sect2>
<sect2> <sect2>
<title><type>timespan</type></title> <title><type>timespan</type></title>
@ -1364,7 +1384,7 @@ where
</sect2> </sect2>
<sect2> <sect2>
<title>abstime</title> <title><type>abstime</type></title>
<para> <para>
Absolute time (<type>abstime</type>) is a limited-range (+/- 68 years) and Absolute time (<type>abstime</type>) is a limited-range (+/- 68 years) and
@ -1407,7 +1427,7 @@ allowed for "absolute time".
</sect2> </sect2>
<sect2> <sect2>
<title>reltime</title> <title><type>reltime</type></title>
<para> <para>
Relative time <type>reltime</type> is a limited-range (+/- 68 years) Relative time <type>reltime</type> is a limited-range (+/- 68 years)
@ -1419,7 +1439,8 @@ relative units (months and years) and quantitative units (days, hours, etc).
Instead, reltime Instead, reltime
must force months to be exactly 30 days, so time arithmetic does not must force months to be exactly 30 days, so time arithmetic does not
always work as expected. always work as expected.
For example, adding one reltime <literal>year</literal> to abstime <literal>today</literal> does not For example, adding one reltime <literal>year</literal> to
abstime <literal>today</literal> does not
produce today's date one year from produce today's date one year from
now, but rather a date 360 days from today. now, but rather a date 360 days from today.
</para> </para>
@ -1461,7 +1482,7 @@ currently mapped to the <type>timespan</type>
</sect2> </sect2>
<sect2> <sect2>
<title>tinterval</title> <title><type>tinterval</type></title>
<para> <para>
Time ranges are specified as: Time ranges are specified as:
@ -1473,8 +1494,10 @@ where
</programlisting> </programlisting>
Special abstime values such as Special abstime values such as
<literal>current', <literal>infinity' and <literal>-infinity' can be used.</literal></literal></literal> <literal>current</literal>, <literal>infinity</literal> and
</para></sect2> <literal>-infinity</literal> can be used.
</para>
</sect2>
</sect1> </sect1>
@ -1631,7 +1654,7 @@ where
<title>Line Segment</title> <title>Line Segment</title>
<para> <para>
Line segments (lseg) are represented by pairs of points. Line segments (<type>lseg</type>) are represented by pairs of points.
</para> </para>
<para> <para>
@ -1691,7 +1714,7 @@ are supplied to select either type in a query.
</para> </para>
<para> <para>
path is specified using the following syntax: <type>path</type> is specified using the following syntax:
<programlisting> <programlisting>
( ( x1 , y1 ) , ... , ( xn , yn ) ) ( ( x1 , y1 ) , ... , ( xn , yn ) )
@ -1704,6 +1727,7 @@ where
a leading "[" indicates an open path a leading "[" indicates an open path
a leading "(" indicates a closed path a leading "(" indicates a closed path
</programlisting> </programlisting>
Paths are output using the first syntax. Paths are output using the first syntax.
Note that <productname>Postgres</productname> versions prior to Note that <productname>Postgres</productname> versions prior to
v6.1 used a format for paths which had a single leading parenthesis, v6.1 used a format for paths which had a single leading parenthesis,
@ -1754,7 +1778,7 @@ Circles are represented by a center point and a radius.
</para> </para>
<para> <para>
circle is specified using the following syntax: <type>circle</type> is specified using the following syntax:
<programlisting> <programlisting>
< ( x , y ) , r > < ( x , y ) , r >
@ -1818,10 +1842,13 @@ variation in representation to represent simple host TCP/IP addresses.
<para> <para>
The <type>cidr</type> type holds a CIDR network. The <type>cidr</type> type holds a CIDR network.
The format for specifying classless networks is <replaceable class="parameter">x.x.x.x/y</replaceable> The format for specifying classless networks is
<replaceable class="parameter">x.x.x.x/y</replaceable>
where <replaceable class="parameter">x.x.x.x</replaceable> is the where <replaceable class="parameter">x.x.x.x</replaceable> is the
network and <replaceable class="parameter">/y</replaceable> is the number of bits in the netmask. network and <replaceable class="parameter">/y</replaceable> is
If <replaceable class="parameter">/y</replaceable> omitted, it is calculated using assumptions from the number of bits in the netmask.
If <replaceable class="parameter">/y</replaceable> omitted, it is
calculated using assumptions from
the older classfull naming system except that it is extended to include at least the older classfull naming system except that it is extended to include at least
all of the octets in the input. all of the octets in the input.
</para> </para>
@ -1885,7 +1912,8 @@ The <type>inet</type> type is designed to hold, in one field, all of the informa
about a host including the CIDR-style subnet that it is in. about a host including the CIDR-style subnet that it is in.
Note that if you want to store proper CIDR networks, Note that if you want to store proper CIDR networks,
you should use the <type>cidr</type> type. you should use the <type>cidr</type> type.
The <type>inet</type> type is similar to the <type>cidr</type> type except that the bits in the The <type>inet</type> type is similar to the <type>cidr</type>
type except that the bits in the
host part can be non-zero. host part can be non-zero.
Functions exist to extract the various elements of the field. Functions exist to extract the various elements of the field.
</para> </para>
@ -1902,7 +1930,8 @@ On output, the <replaceable class="parameter">/y</replaceable> part is not print
if it is <literal>/32</literal>. if it is <literal>/32</literal>.
This allows the type to be used as a straight host type by just leaving off This allows the type to be used as a straight host type by just leaving off
the bits part. the bits part.
</para></sect2> </para>
</sect2>
</sect1> </sect1>
</chapter> </chapter>