</indexterm>

<para>

The catalog <structname>pg_range</structname> stores information about range types.

The catalog <structname>pg_range</structname> stores information about

range types. This is in addition to the types' entries in

<link linkend="catalog-pg-type"><structname>pg_type</structname></link>.

</para>

<table>

<entry><structfield>rngtypid</structfield></entry>

<entry><type>oid</type></entry>

<entry><literal><link linkend="catalog-pg-type"><structname>pg_type</structname></link>.oid</literal></entry>

<entry>The type that is a range type</entry>

<entry>OID of the range type</entry>

</row>

<row>

<entry><structfield>rngsubtype</structfield></entry>

<entry><type>oid</type></entry>

<entry><literal><link linkend="catalog-pg-type"><structname>pg_type</structname></link>.oid</literal></entry>

<entry>Subtype ofthis range type, e.g. <type>integer</type> is thesubtype of<type>int4range</type></entry>

<entry>OID ofthe element type (subtype) ofthis rangetype</entry>

</row>

<row>

<entry><structfield>rngcollation</structfield></entry>

<entry><type>oid</type></entry>

<entry><literal><link linkend="catalog-pg-collation"><structname>pg_collation</structname></link>.oid</literal></entry>

<entry>Thecollation usedwhen comparingrangeboundaries</entry>

<entry>OID of thecollation usedforrangecomparisons, or 0 if none</entry>

</row>

<row>

<entry><structfield>rngsubopc</structfield></entry>

<entry><type>oid</type></entry>

<entry><literal><link linkend="catalog-pg-opclass"><structname>pg_opclass</structname></link>.oid</literal></entry>

<entry>Theoperator class usedwhen comparingrangeboundaries</entry>

<entry>OID of the subtype'soperator class usedforrangecomparisons</entry>

</row>

<row>

<entry><structfield>rngcanonical</structfield></entry>

<entry><type>regproc</type></entry>

<entry><literal><link linkend="catalog-pg-proc"><structname>pg_proc</structname></link>.oid</literal></entry>

<entry>A function to convert a range into its canonical form</entry>

<entry>OID of the function to convert a range value into canonical form,

or 0 if none</entry>

</row>

<row>

<entry><structfield>rngsubdiff</structfield></entry>

<entry><type>regproc</type></entry>

<entry><literal><link linkend="catalog-pg-proc"><structname>pg_proc</structname></link>.oid</literal></entry>

<entry>A function to return the distance between two lower and upper bound, as a <type>double precision</type>. Used for GiST support</entry>

<entry>OID of the function to return the difference between two element

values as <type>double precision</type>, or 0 if none</entry>

</row>

</tbody>

</tgroup>

</table>

<para>

<structfield>rngsubopc</> (plus <structfield>rngcollation</>, if the

element type is collatable) determines the sort ordering used by the range

type. <structfield>rngcanonical</> is used when the element type is

discrete. <structfield>rngsubdiff</> is optional but should be supplied to

improve performance of GiST indexes on the range type.

</para>

</sect1>

<sect1 id="catalog-pg-rewrite">

<literal>c</literal> for a composite type (e.g., a table's row type),

<literal>d</literal> for a domain,

<literal>e</literal> for an enum type,

or <literal>p</literal> for a pseudo-type.

<literal>p</literal> for a pseudo-type, or

<literal>r</literal> for a range type.

See also <structfield>typrelid</structfield> and

<structfield>typbasetype</structfield>.

</entry>

<entry><literal>P</literal></entry>

<entry>Pseudo-types</entry>

</row>

<row>

<entry><literal>R</literal></entry>

<entry>Range types</entry>

</row>

<row>

<entry><literal>S</literal></entry>

<entry>String types</entry>

<para>

Five pseudo-types of special interest are <type>anyelement</>,

<type>anyarray</>, <type>anynonarray</>, <type>anyenum</>,

and <type>anyrange</>, which are collectively

called <firstterm>polymorphic types</>. Any function declared

using these types is said to be a <firstterm>polymorphic

function</>. A polymorphic function can operate on many

different data types, with the specific data type(s) being

determined by the data types actually passed to it in a

particularcall.

and <type>anyrange</>,

which are collectivelycalled <firstterm>polymorphic types</>.

Any function declaredusing these types is said to be

a <firstterm>polymorphicfunction</>. A polymorphic function can

operate on manydifferent data types, with the specific data type(s)

beingdetermined by the data types actually passed to it in a particular

call.

</para>

<para>

data type, but in any given call they must all be the

<emphasis>same</emphasis> actual type. Each

position declared as <type>anyarray</type> can have any array data type,

but similarly they must all be the same type. If there are

but similarly they must all be the same type. And similarly,

positions declared as <type>anyrange</type> must all be the same range

type. Furthermore, if there are

positions declared <type>anyarray</type> and others declared

<type>anyelement</type>, the actual array type in the

<type>anyarray</type> positions must be an array whose elements are

the same type appearing in the <type>anyelement</type> positions.

Similarly, if there are positions declared <type>anyrange</type>

and others declared

<type>anyelement</type>, the actual range type in the

<type>anyrange</type> positions must be a range whose subtype is

and others declared <type>anyelement</type>, the actual range type in

the <type>anyrange</type> positions must be a range whose subtype is

the same type appearing in the <type>anyelement</type> positions.

<type>anynonarray</> is treated exactly the same as <type>anyelement</>,

but adds the additional constraint that the actual type must not be

<row>

<entry> <literal>@&gt;</literal> </entry>

<entry>contains</entry>

<entry>contains range</entry>

<entry><literal>int4range(2,4) @&gt; int4range(2,3)</literal></entry>

<entry><literal>t</literal></entry>

</row>

<row>

<entry> <literal>@&gt;</literal> </entry>

<entry>contains element</entry>

<entry><literal>'[2011-01-01,2011-03-01)'::tsrange @&gt; '2011-01-10'::timestamp</literal></entry>

<entry><literal>t</literal></entry>

</row>

<row>

<entry> <literal>&lt;@</literal> </entry>

<entry>is contained by</entry>

<entry>rangeis contained by</entry>

<entry><literal>int4range(2,4) &lt;@ int4range(1,7)</literal></entry>

<entry><literal>t</literal></entry>

</row>

<row>

<entry> <literal>&lt;@</literal> </entry>

<entry>element is contained by</entry>

<entry><literal>42 &lt;@ int4range(1,7)</literal></entry>

<entry><literal>f</literal></entry>

</row>

<row>

<entry> <literal>&amp;&amp;</literal> </entry>

<entry>overlap (have points in common)</entry>