diff options
author | Tom Lane <tgl@sss.pgh.pa.us> | 2003-12-01 20:34:53 +0000 |
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committer | Tom Lane <tgl@sss.pgh.pa.us> | 2003-12-01 20:34:53 +0000 |
commit | af03663878b257f7fb93a80eec03a8dd070b22b7 (patch) | |
tree | 811ed6433586c6ee963fea987f9c2e33acda9cdd | |
parent | c5336a892f18614e78f12a840c89073ffed2c144 (diff) | |
download | postgresql-af03663878b257f7fb93a80eec03a8dd070b22b7.tar.gz postgresql-af03663878b257f7fb93a80eec03a8dd070b22b7.zip |
Minor wordsmithing in datetime docs to try to address gripes raised by
cnliou.
-rw-r--r-- | doc/src/sgml/datatype.sgml | 33 | ||||
-rw-r--r-- | doc/src/sgml/datetime.sgml | 18 |
2 files changed, 31 insertions, 20 deletions
diff --git a/doc/src/sgml/datatype.sgml b/doc/src/sgml/datatype.sgml index 7707aed2a47..a214f5398c8 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 1.133 2003/11/30 20:55:09 joe Exp $ +$PostgreSQL: pgsql/doc/src/sgml/datatype.sgml,v 1.134 2003/12/01 20:34:53 tgl Exp $ --> <chapter id="datatype"> @@ -1301,7 +1301,7 @@ SELECT b, char_length(b) FROM test2; <entry>8 bytes</entry> <entry>both date and time</entry> <entry>4713 BC</entry> - <entry>AD 5874897</entry> + <entry>5874897 AD</entry> <entry>1 microsecond / 14 digits</entry> </row> <row> @@ -1309,7 +1309,7 @@ SELECT b, char_length(b) FROM test2; <entry>8 bytes</entry> <entry>both date and time, with time zone</entry> <entry>4713 BC</entry> - <entry>AD 5874897</entry> + <entry>5874897 AD</entry> <entry>1 microsecond / 14 digits</entry> </row> <row> @@ -1348,6 +1348,14 @@ SELECT b, char_length(b) FROM test2; </tgroup> </table> + <note> + <para> + Prior to <productname>PostgreSQL</productname> 7.3, writing just + <type>timestamp</type> was equivalent to <type>timestamp with + time zone</type>. This was changed for SQL compliance. + </para> + </note> + <para> <type>time</type>, <type>timestamp</type>, and <type>interval</type> accept an optional precision value @@ -1363,23 +1371,16 @@ SELECT b, char_length(b) FROM test2; When <type>timestamp</> values are stored as double precision floating-point numbers (currently the default), the effective limit of precision may be less than 6. <type>timestamp</type> values are stored as seconds - since 2000-01-01, and microsecond precision is achieved for dates within - a few years of 2000-01-01, but the precision degrades for dates further - away. When <type>timestamp</type> values are stored as eight-byte integers (a compile-time + before or after midnight 2000-01-01. Microsecond precision is achieved for + dates within a few years of 2000-01-01, but the precision degrades for + dates further away. When <type>timestamp</type> values are stored as + eight-byte integers (a compile-time option), microsecond precision is available over the full range of - values. However eight-byte integer timestamps have a reduced range of - dates from 4713 BC up to 294276 AD. + values. However eight-byte integer timestamps have a more limited range of + dates than shown above: from 4713 BC up to 294276 AD. </para> </note> - <note> - <para> - Prior to <productname>PostgreSQL</productname> 7.3, writing just - <type>timestamp</type> was equivalent to <type>timestamp with - time zone</type>. This was changed for SQL compliance. - </para> - </note> - <para> For the <type>time</type> types, the allowed range of <replaceable>p</replaceable> is from 0 to 6 when eight-byte integer diff --git a/doc/src/sgml/datetime.sgml b/doc/src/sgml/datetime.sgml index 93315564c86..d1f82c9d6e5 100644 --- a/doc/src/sgml/datetime.sgml +++ b/doc/src/sgml/datetime.sgml @@ -1,5 +1,5 @@ <!-- -$PostgreSQL: pgsql/doc/src/sgml/datetime.sgml,v 2.38 2003/11/29 19:51:36 pgsql Exp $ +$PostgreSQL: pgsql/doc/src/sgml/datetime.sgml,v 2.39 2003/12/01 20:34:53 tgl Exp $ --> <appendix id="datetime-appendix"> @@ -370,9 +370,10 @@ $PostgreSQL: pgsql/doc/src/sgml/datetime.sgml,v 2.38 2003/11/29 19:51:36 pgsql E <para> <xref linkend="datetime-timezone-table"> shows the time zone - abbreviations recognized by <productname>PostgreSQL</productname>. - <productname>PostgreSQL</productname> contains internal tabular - information for time zone decoding, since there is no standard + abbreviations recognized by <productname>PostgreSQL</productname> + in date/time input values. + <productname>PostgreSQL</productname> uses internal tables + for time zone input decoding, since there is no standard operating system interface to provide access to general, cross-time zone information. The underlying operating system <emphasis>is</emphasis> used to provide time zone information for @@ -380,6 +381,15 @@ $PostgreSQL: pgsql/doc/src/sgml/datetime.sgml,v 2.38 2003/11/29 19:51:36 pgsql E </para> <para> + Keep in mind also that the time zone names + recognized by <command>SET TIMEZONE</> are operating-system + dependent and may have little to do with <xref + linkend="datetime-timezone-table">. For example, some systems + recognize values like <literal>'Europe/Rome'</> in <command>SET + TIMEZONE</>. + </para> + + <para> The table is organized by time zone offset from <acronym>UTC</>, rather than alphabetically. This is intended to facilitate matching local usage with recognized abbreviations for cases where |