|
|
|
@ -1,4 +1,4 @@ |
|
|
|
|
<!-- $PostgreSQL: pgsql/doc/src/sgml/datatype.sgml,v 1.251 2010/07/16 02:15:53 tgl Exp $ --> |
|
|
|
|
<!-- $PostgreSQL: pgsql/doc/src/sgml/datatype.sgml,v 1.252 2010/07/24 12:17:35 petere Exp $ --> |
|
|
|
|
|
|
|
|
|
<chapter id="datatype"> |
|
|
|
|
<title>Data Types</title> |
|
|
|
@ -2759,13 +2759,34 @@ P <optional> <replaceable>years</>-<replaceable>months</>-<replaceable>days</> < |
|
|
|
|
|
|
|
|
|
<para> |
|
|
|
|
<productname>PostgreSQL</productname> provides the |
|
|
|
|
standard <acronym>SQL</acronym> type <type>boolean</type>. |
|
|
|
|
<type>boolean</type> can have one of only two states: |
|
|
|
|
standard <acronym>SQL</acronym> type <type>boolean</type>; |
|
|
|
|
see <xref linkend="datatype-boolean-table">. |
|
|
|
|
The <type>boolean</type> type can have one of only two states: |
|
|
|
|
<quote>true</quote> or <quote>false</quote>. A third state, |
|
|
|
|
<quote>unknown</quote>, is represented by the |
|
|
|
|
<acronym>SQL</acronym> null value. |
|
|
|
|
</para> |
|
|
|
|
|
|
|
|
|
<table id="datatype-boolean-table"> |
|
|
|
|
<title>Boolean Data Type</title> |
|
|
|
|
<tgroup cols="3"> |
|
|
|
|
<thead> |
|
|
|
|
<row> |
|
|
|
|
<entry>Name</entry> |
|
|
|
|
<entry>Storage Size</entry> |
|
|
|
|
<entry>Description</entry> |
|
|
|
|
</row> |
|
|
|
|
</thead> |
|
|
|
|
<tbody> |
|
|
|
|
<row> |
|
|
|
|
<entry><type>boolean</type></entry> |
|
|
|
|
<entry>1 byte</entry> |
|
|
|
|
<entry>state of true of false</entry> |
|
|
|
|
</row> |
|
|
|
|
</tbody> |
|
|
|
|
</tgroup> |
|
|
|
|
</table> |
|
|
|
|
|
|
|
|
|
<para> |
|
|
|
|
Valid literal values for the <quote>true</quote> state are: |
|
|
|
|
<simplelist> |
|
|
|
@ -2794,6 +2815,12 @@ P <optional> <replaceable>years</>-<replaceable>months</>-<replaceable>days</> < |
|
|
|
|
(<acronym>SQL</acronym>-compliant) usage. |
|
|
|
|
</para> |
|
|
|
|
|
|
|
|
|
<para> |
|
|
|
|
<xref linkend="datatype-boolean-example"> shows that |
|
|
|
|
<type>boolean</type> values are output using the letters |
|
|
|
|
<literal>t</literal> and <literal>f</literal>. |
|
|
|
|
</para> |
|
|
|
|
|
|
|
|
|
<example id="datatype-boolean-example"> |
|
|
|
|
<title>Using the <type>boolean</type> type</title> |
|
|
|
|
|
|
|
|
@ -2813,16 +2840,6 @@ SELECT * FROM test1 WHERE a; |
|
|
|
|
t | sic est |
|
|
|
|
</programlisting> |
|
|
|
|
</example> |
|
|
|
|
|
|
|
|
|
<para> |
|
|
|
|
<xref linkend="datatype-boolean-example"> shows that |
|
|
|
|
<type>boolean</type> values are output using the letters |
|
|
|
|
<literal>t</literal> and <literal>f</literal>. |
|
|
|
|
</para> |
|
|
|
|
|
|
|
|
|
<para> |
|
|
|
|
<type>boolean</type> uses 1 byte of storage. |
|
|
|
|
</para> |
|
|
|
|
</sect1> |
|
|
|
|
|
|
|
|
|
<sect1 id="datatype-enum"> |
|
|
|
|