<entry><type>double precision</type></entry>
        <entry>8 bytes</entry>
        <entry>variable-precision, inexact</entry>
        <entry>15 decimal digits precision</entry>
       </row>

       <row>
        <entry><type>smallserial</type></entry>
        <entry>2 bytes</entry>
        <entry>small autoincrementing integer</entry>
        <entry>1 to 32767</entry>
       </row>

       <row>
        <entry><type>serial</type></entry>
        <entry>4 bytes</entry>
        <entry>autoincrementing integer</entry>
        <entry>1 to 2147483647</entry>
       </row>

       <row>
        <entry><type>bigserial</type></entry>
        <entry>8 bytes</entry>
        <entry>large autoincrementing integer</entry>
        <entry>1 to 9223372036854775807</entry>
       </row>
      </tbody>
     </tgroup>
    </table>

   <para>
    The syntax of constants for the numeric types is described in
    <xref linkend="sql-syntax-constants"/>.  The numeric types have a
    full set of corresponding arithmetic operators and
    functions. Refer to <xref linkend="functions"/> for more
    information.  The following sections describe the types in detail.
   </para>

   <sect2 id="datatype-int">
    <title>Integer Types</title>

    <indexterm zone="datatype-int">
     <primary>integer</primary>
    </indexterm>

    <indexterm zone="datatype-int">
     <primary>smallint</primary>
    </indexterm>

    <indexterm zone="datatype-int">
     <primary>bigint</primary>
    </indexterm>

    <indexterm>
     <primary>int4</primary>
     <see>integer</see>
    </indexterm>

    <indexterm>
     <primary>int2</primary>
     <see>smallint</see>
    </indexterm>

    <indexterm>
     <primary>int8</primary>
     <see>bigint</see>
    </indexterm>

    <para>
     The types <type>smallint</type>, <type>integer</type>, and
     <type>bigint</type> store whole numbers, that is, numbers without
     fractional components, of various ranges.  Attempts to store
     values outside of the allowed range will result in an error.
    </para>

    <para>
     The type <type>integer</type> is the common choice, as it offers
     the best balance between range, storage size, and performance.
     The <type>smallint</type> type is generally only used if disk
     space is at a premium.  The <type>bigint</type> type is designed to be
     used when the range of the <type>integer</type> type is insufficient.
    </para>

    <para>
     <acronym>SQL</acronym> only specifies the integer types
     <type>integer</type> (or <type>int</type>),
     <type>smallint</type>, and <type>bigint</type>.  The
     type names <type>int2</type>, <type>int4</type>, and
     <type>int8</type> are extensions, which are also used by some
     other <acronym>SQL</acronym> database systems.
    </para>

   </sect2>

   <sect2 id="datatype-numeric-decimal">
    <title>Arbitrary Precision Numbers</title>

    <indexterm>
     <primary>numeric (data type)</primary>
    </indexterm>

   <indexterm>
    <primary>arbitrary precision numbers</primary>
   </indexterm>

    <indexterm>
     <primary>decimal</primary>
     <see>numeric</see>
    </indexterm>

    <para>
     The type <type>numeric</type> can store numbers with a
     very large number of digits. It is especially recommended for
     storing monetary amounts and other quantities where exactness is
     required.  Calculations with <type>numeric</type> values yield exact
     results where possible, e.g.,  addition, subtraction, multiplication.
     However, calculations on <type>numeric</type> values are very slow
     compared to the integer types, or to the floating-point types
     described in the next section.
    </para>

    <para>
     We use the following terms below:  The
     <firstterm>precision</firstterm> of a <type>numeric</type>
     is the total count of significant digits in the whole number,
     that is, the number of digits to both sides of the decimal point.
     The <firstterm>scale</firstterm> of a <type>numeric</type>