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| author | Bruce Momjian <bruce@momjian.us> | 2005-12-22 21:45:30 +0000 |
|---|---|---|
| committer | Bruce Momjian <bruce@momjian.us> | 2005-12-22 21:45:30 +0000 |
| commit | f545a05704e5148fec1f373820603cc7be73e7dd (patch) | |
| tree | a8425092987c209d1800b252726d81e0284c0074 | |
| parent | 14e9a17f0a08a908567867cd77b274320e1280f8 (diff) | |
| download | postgresql-f545a05704e5148fec1f373820603cc7be73e7dd.tar.gz postgresql-f545a05704e5148fec1f373820603cc7be73e7dd.zip | |
Update interval documenation to mention the storage system used.
| -rw-r--r-- | doc/src/sgml/datatype.sgml | 21 |
1 files changed, 16 insertions, 5 deletions
diff --git a/doc/src/sgml/datatype.sgml b/doc/src/sgml/datatype.sgml index 03732ba9cab..01cc93c8e05 100644 --- a/doc/src/sgml/datatype.sgml +++ b/doc/src/sgml/datatype.sgml @@ -1,5 +1,5 @@ <!-- -$PostgreSQL: pgsql/doc/src/sgml/datatype.sgml,v 1.163 2005/10/22 19:33:57 tgl Exp $ +$PostgreSQL: pgsql/doc/src/sgml/datatype.sgml,v 1.163.2.1 2005/12/22 21:45:30 momjian Exp $ --> <chapter id="datatype"> @@ -1841,9 +1841,20 @@ January 8 04:05:06 1999 PST </para> <para> - The optional precision - <replaceable>p</replaceable> should be between 0 and 6, and - defaults to the precision of the input literal. + The optional subsecond precision <replaceable>p</replaceable> should + be between 0 and 6, and defaults to the precision of the input literal. + </para> + + <para> + Internally <type>interval</> values are stored as months, days, + and seconds. This is done because the number of days in a month + varies, and a day can have 23 or 25 hours if a daylight savings + time adjustment is involved. Because intervals are usually created + from constant strings or <type>timestamp</> subtraction, this + storage method works well in most cases. Functions + <function>justify_days</> and <function>justify_hours</> are + available for adjusting days and hours that overflow their normal + periods. </para> </sect3> @@ -1936,7 +1947,7 @@ January 8 04:05:06 1999 PST <literal>CURRENT_DATE</literal>, <literal>CURRENT_TIME</literal>, <literal>CURRENT_TIMESTAMP</literal>, <literal>LOCALTIME</literal>, <literal>LOCALTIMESTAMP</literal>. The latter four accept an - optional precision specification. (See <xref + optional subsecond precision specification. (See <xref linkend="functions-datetime-current">.) Note however that these are SQL functions and are <emphasis>not</> recognized as data input strings. </para> |