<!-- doc/src/sgml/datatype.sgml -->

 <chapter id="datatype">
  <title>Data Types</title>

  <indexterm zone="datatype">
   <primary>data type</primary>
  </indexterm>

  <indexterm>
   <primary>type</primary>
   <see>data type</see>
  </indexterm>

  <para>
   <productname>PostgreSQL</productname> has a rich set of native data
   types available to users.  Users can add new types to
   <productname>PostgreSQL</productname> using the <xref
   linkend="sql-createtype"/> command.
  </para>

  <para>
   <xref linkend="datatype-table"/> shows all the built-in general-purpose data
   types. Most of the alternative names listed in the
   <quote>Aliases</quote> column are the names used internally by
   <productname>PostgreSQL</productname> for historical reasons.  In
   addition, some internally used or deprecated types are available,
   but are not listed here.
  </para>

   <table id="datatype-table">
    <title>Data Types</title>
    <tgroup cols="3">
     <colspec colname="col1" colwidth="2*"/>
     <colspec colname="col2" colwidth="1*"/>
     <colspec colname="col3" colwidth="2*"/>
     <thead>
      <row>
       <entry>Name</entry>
       <entry>Aliases</entry>
       <entry>Description</entry>
      </row>
     </thead>

     <tbody>
      <row>
       <entry><type>bigint</type></entry>
       <entry><type>int8</type></entry>
       <entry>signed eight-byte integer</entry>
      </row>

      <row>
       <entry><type>bigserial</type></entry>
       <entry><type>serial8</type></entry>
       <entry>autoincrementing eight-byte integer</entry>
      </row>

      <row>
       <entry><type>bit [ (<replaceable>n</replaceable>) ]</type></entry>
       <entry></entry>
       <entry>fixed-length bit string</entry>
      </row>

      <row>
       <entry><type>bit varying [ (<replaceable>n</replaceable>) ]</type></entry>
       <entry><type>varbit [ (<replaceable>n</replaceable>) ]</type></entry>
       <entry>variable-length bit string</entry>
      </row>

      <row>
       <entry><type>boolean</type></entry>
       <entry><type>bool</type></entry>
       <entry>logical Boolean (true/false)</entry>
      </row>

      <row>
       <entry><type>box</type></entry>
       <entry></entry>
       <entry>rectangular box on a plane</entry>
      </row>

      <row>
       <entry><type>bytea</type></entry>
       <entry></entry>
       <entry>binary data (<quote>byte array</quote>)</entry>
      </row>

      <row>
       <entry><type>character [ (<replaceable>n</replaceable>) ]</type></entry>
       <entry><type>char [ (<replaceable>n</replaceable>) ]</type></entry>
       <entry>fixed-length character string</entry>
      </row>

      <row>
       <entry><type>character varying [ (<replaceable>n</replaceable>) ]</type></entry>
       <entry><type>varchar [ (<replaceable>n</replaceable>) ]</type></entry>
       <entry>variable-length character string</entry>
      </row>

      <row>
       <entry><type>cidr</type></entry>
       <entry></entry>
       <entry>IPv4 or IPv6 network address</entry>
      </row>

      <row>
       <entry><type>circle</type></entry>
       <entry></entry>
       <entry>circle on a plane</entry>
      </row>

      <row>
       <entry><type>date</type></entry>
       <entry></entry>
       <entry>calendar date (year, month, day)</entry>
      </row>

      <row>
       <entry><type>double precision</type></entry>
       <entry><type>float8</type></entry>
       <entry>double precision floating-point number (8 bytes)</entry>
      </row>

      <row>
       <entry><type>inet</type></entry>
       <entry></entry>
       <entry>IPv4 or IPv6 host address</entry>
      </row>

      <row>
       <entry><type>integer</type></entry>
       <entry><type>int</type>, <type>int4</type></entry>
       <entry>signed four-byte integer</entry>
      </row>

      <row>
       <entry><type>interval [ <replaceable>fields</replaceable> ] [ (<replaceable>p</replaceable>) ]</type></entry>
       <entry></entry>
       <entry>time