$Header: /cvsroot/pgsql/doc/src/sgml/ref/create_table.sgml,v 1.21 2000/04/12 04:40:03 thomas Exp $

<para>

In the current release (v7.0), <productname>Postgres</productname>

evaluates all default expressions at the time the table is defined.

Hence, functions which are "non-cacheable" such as

<function>CURRENT_TIMESTAMP</function> may not produce the desired

effect. For the particular case of date/time types, one can work

around this behavior by using

<quote>DEFAULT TEXT 'now'</quote>

instead of

<quote>DEFAULT 'now'</quote>

or

<quote>DEFAULT CURRENT_TIMESTAMP</quote>.

This forces <productname>Postgres</productname> to consider the constant a string

type and then to convert the value to <type>timestamp</type> at runtime.

</para>