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-$Header: /cvsroot/pgsql/doc/src/sgml/func.sgml,v 1.126 2002/09/24 20:14:58 petere Exp $
+$Header: /cvsroot/pgsql/doc/src/sgml/func.sgml,v 1.127 2002/10/05 19:03:16 momjian Exp $
PostgreSQL documentation
-->
<entry>01110</entry>
</row>
<row>
- <entry>B'10001' << 3</entry>
+ <entry>B'10001' << 3</entry>
<entry>01000</entry>
</row>
<row>
- <entry>B'10001' >> 2</entry>
+ <entry>B'10001' >> 2</entry>
<entry>00100</entry>
</row>
</tbody>
<para>
There are two special cases of bracket expressions: the bracket
- expressions <literal>[[:<:]]</literal> and
+ expressions <literal>[[:<:]]</literal> and
<literal>[[:>:]]</literal> match the null string at the beginning
and end of a word respectively. A word is defined as a sequence
of word characters which is neither preceded nor followed by word
</row>
<row>
<entry><literal>MI</literal></entry>
- <entry>minus sign in specified position (if number < 0)</entry>
+ <entry>minus sign in specified position (if number < 0)</entry>
</row>
<row>
<entry><literal>PL</literal></entry>
- <entry>plus sign in specified position (if number > 0)</entry>
+ <entry>plus sign in specified position (if number > 0)</entry>
</row>
<row>
<entry><literal>SG</literal></entry>
</informalexample>
<para>
- It is quite important to realize that
- <function>CURRENT_TIMESTAMP</function> and related functions all return
- the time as of the start of the current transaction; their values do not
- increment while a transaction is running. But
- <function>timeofday()</function> returns the actual current time.
+ It is important to realize that
+ <function>CURRENT_TIMESTAMP</function> and related functions return
+ the start time of the current transaction; their values do not
+ change during the transaction. <function>timeofday()</function>
+ returns the wall clock time and does advance during transactions.
</para>
+ <note>
+ Many other database systems advance these values more
+ frequently.
+ </note>
+
<para>
All the date/time data types also accept the special literal value
<literal>now</literal> to specify the current date and time. Thus,