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Postgres FD Implementation
Commit c00d800e authored by Thomas G. Lockhart's avatar Thomas G. Lockhart
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Add tables of allowed values and formats for date/time input types. 

Include info for time zones, days of week, months.
Procedural description of date input parsing is not yet complete.
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doc/src/sgml/datatype.sgml
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...@@ -881,29 +881,29 @@ the time zone becomes GMT (on most systems anyway). ...@@ -881,29 +881,29 @@ the time zone becomes GMT (on most systems anyway).
</para> </para>
</sect2> </sect2>
<sect2> <sect2>
<title>Date/Time Input</title> <title>Date/Time Input</title>
<para> <para>
General-use date and time is input using a wide range of General-use date and time is input using a wide range of
styles, including ISO-compatible, <acronym>SQL</acronym>-compatible, styles, including ISO-compatible, <acronym>SQL</acronym>-compatible,
traditional <productname>Postgres</productname> traditional <productname>Postgres</productname>
and other permutations of date and time. In cases where interpretation and other permutations of date and time. In cases where interpretation
can be ambiguous (quite possible with many traditional styles of date can be ambiguous (quite possible with many traditional styles of date
specification) <productname>Postgres</productname> uses a style setting specification) <productname>Postgres</productname> uses a style setting
to resolve the ambiguity. to resolve the ambiguity.
</para> </para>
<para> <para>
Most date and time types share code for data input. For those types Most date and time types share code for data input. For those types
the input can have any of a wide variety of styles. For numeric date the input can have any of a wide variety of styles. For numeric date
representations, representations,
European and US conventions can differ, and the proper interpretation European and US conventions can differ, and the proper interpretation
is obtained by using the <command>SET DATESTYLE</command> is obtained by using the <command>SET DATESTYLE</command>
command before entering data. command before entering data.
Note that the style setting does not preclude use of various styles for input; Note that the style setting does not preclude use of various styles for input;
it is used primarily to determine the output style and to resolve ambiguities. it is used primarily to determine the output style and to resolve ambiguities.
</para> </para>
<para> <para>
The special values <literal>current</literal>, The special values <literal>current</literal>,
...@@ -915,74 +915,846 @@ Note that the style setting does not preclude use of various styles for input; ...@@ -915,74 +915,846 @@ Note that the style setting does not preclude use of various styles for input;
</para> </para>
<para> <para>
The strings The strings
<literal>now</literal>, <literal>now</literal>,
<literal>today</literal>, <literal>today</literal>,
<literal>yesterday</literal>, <literal>yesterday</literal>,
<literal>tomorrow</literal>, <literal>tomorrow</literal>,
and <literal>epoch</literal> and <literal>epoch</literal>
can be used to specify can be used to specify time values.
time values. <literal>now</literal> <literal>now</literal>
means the current transaction time, and differs from means the current transaction time, and differs from
<literal>current</literal> <literal>current</literal>
in that the current time is immediately substituted in that the current time is immediately substituted for it.
for it. <literal>epoch</literal> <literal>epoch</literal> means <literal>Jan 1 00:00:00 1970 GMT</literal>.
means Jan 1 00:00:00 1970 GMT. </para>
</para>
<para> <para>
<table tocentry="1"> <table tocentry="1">
<title><productname>Postgres</productname> Date/Time Special Constants</title> <title><productname>Postgres</productname> Date/Time Special Constants</title>
<titleabbrev>Constants</titleabbrev> <titleabbrev>Constants</titleabbrev>
<tgroup cols="2"> <tgroup cols="2">
<thead> <thead>
<row> <row>
<entry>Constant</entry> <entry>Constant</entry>
<entry>Description</entry> <entry>Description</entry>
</row> </row>
</thead> </thead>
<tbody> <tbody>
<row> <row>
<entry>current</entry> <entry>current</entry>
<entry>Current transaction time, deferred</entry> <entry>Current transaction time, deferred</entry>
</row> </row>
<row> <row>
<entry>epoch</entry> <entry>epoch</entry>
<entry>1970-01-01 00:00:00+00 (Unix system time zero)</entry> <entry>1970-01-01 00:00:00+00 (Unix system time zero)</entry>
</row> </row>
<row> <row>
<entry>infinity</entry> <entry>infinity</entry>
<entry>Later than other valid times</entry> <entry>Later than other valid times</entry>
</row> </row>
<row> <row>
<entry>-infinity</entry> <entry>-infinity</entry>
<entry>Earlier than other valid times</entry> <entry>Earlier than other valid times</entry>
</row> </row>
<row> <row>
<entry>invalid</entry> <entry>invalid</entry>
<entry>Illegal entry</entry> <entry>Illegal entry</entry>
</row> </row>
<row> <row>
<entry>now</entry> <entry>now</entry>
<entry>Current transaction time</entry> <entry>Current transaction time</entry>
</row> </row>
<row> <row>
<entry>today</entry> <entry>today</entry>
<entry>Midnight today</entry> <entry>Midnight today</entry>
</row> </row>
<row> <row>
<entry>tomorrow</entry> <entry>tomorrow</entry>
<entry>Midnight tomorrow</entry> <entry>Midnight tomorrow</entry>
</row> </row>
<row> <row>
<entry>yesterday</entry> <entry>yesterday</entry>
<entry>Midnight yesterday</entry> <entry>Midnight yesterday</entry>
</row> </row>
</tbody> </tbody>
</tgroup> </tgroup>
</table> </table>
</para> </para>
<para>
<table tocentry="1">
<title><productname>Postgres</productname> Date Input</title>
<titleabbrev>Date Inputs</titleabbrev>
<tgroup cols="2">
<thead>
<row>
<entry>Example</entry>
<entry>Description</entry>
</row>
</thead>
<tbody>
<row>
<entry>January 8, 1999</entry>
<entry>Unambiguous text month</entry>
</row>
<row>
<entry>1999-01-08</entry>
<entry>ISO-8601</entry>
</row>
<row>
<entry>1/8/1999</entry>
<entry>US; read as August 1 in European mode</entry>
</row>
<row>
<entry>8/1/1999</entry>
<entry>European; read as August 1 in US mode</entry>
</row>
<row>
<entry>1/18/1999</entry>
<entry>US; read as January 18 in any mode</entry>
</row>
<row>
<entry>1999.008</entry>
<entry>Year and day of year</entry>
</row>
<row>
<entry>19990108</entry>
<entry>ISO-8601 year, month, day</entry>
</row>
<row>
<entry>990108</entry>
<entry>ISO-8601 year, month, day</entry>
</row>
<row>
<entry>1999.008</entry>
<entry>Year and day of year</entry>
</row>
<row>
<entry>99008</entry>
<entry>Year and day of year</entry>
</row>
<row>
<entry>January 8, 99 BC</entry>
<entry>Year 99 before the Christian Era</entry>
</row>
</tbody>
</tgroup>
</table>
</para>
<para>
<table tocentry="1">
<title><productname>Postgres</productname> Month Abbreviations</title>
<titleabbrev>Month Abbreviations</titleabbrev>
<tgroup cols="2">
<thead>
<row>
<entry>Month</entry>
<entry>Abbreviations</entry>
</row>
</thead>
<tbody>
<row>
<entry>April</entry>
<entry>Apr</entry>
</row>
<row>
<entry>August</entry>
<entry>Aug</entry>
</row>
<row>
<entry>December</entry>
<entry>Dec</entry>
</row>
<row>
<entry>February</entry>
<entry>Feb</entry>
</row>
<row>
<entry>January</entry>
<entry>Jan</entry>
</row>
<row>
<entry>July</entry>
<entry>Jul</entry>
</row>
<row>
<entry>June</entry>
<entry>Jun</entry>
</row>
<row>
<entry>March</entry>
<entry>Mar</entry>
</row>
<row>
<entry>November</entry>
<entry>Nov</entry>
</row>
<row>
<entry>October</entry>
<entry>Oct</entry>
</row>
<row>
<entry>September</entry>
<entry>Sep, Sept</entry>
</row>
</tbody>
</tgroup>
</table>
<note>
<para>
The month <literal>May</literal> has no explicit abbreviation, for obvious reasons.
</para>
</note>
</para>
<para>
<table tocentry="1">
<title><productname>Postgres</productname> Day of Week Abbreviations</title>
<titleabbrev>Day of Week Abbreviations</titleabbrev>
<tgroup cols="2">
<thead>
<row>
<entry>Day</entry>
<entry>Abbreviation</entry>
</row>
</thead>
<tbody>
<row>
<entry>Sunday</entry>
<entry>Sun</entry>
</row>
<row>
<entry>Monday</entry>
<entry>Mon</entry>
</row>
<row>
<entry>Tuesday</entry>
<entry>Tue, Tues</entry>
</row>
<row>
<entry>Wednesday</entry>
<entry>Wed, Weds</entry>
</row>
<row>
<entry>Thursday</entry>
<entry>Thu, Thur, Thurs</entry>
</row>
<row>
<entry>Friday</entry>
<entry>Fri</entry>
</row>
<row>
<entry>Saturday</entry>
<entry>Sat</entry>
</row>
</tbody>
</tgroup>
</table>
</para>
<para>
<table tocentry="1">
<title><productname>Postgres</productname> Time Input</title>
<titleabbrev>Time Inputs</titleabbrev>
<tgroup cols="2">
<thead>
<row>
<entry>Example</entry>
<entry>Description</entry>
</row>
</thead>
<tbody>
<row>
<entry>04:05:06.789</entry>
<entry>ISO-8601, with all time fields</entry>
</row>
<row>
<entry>04:05:06</entry>
<entry>ISO-8601</entry>
</row>
<row>
<entry>04:05</entry>
<entry>ISO-8601</entry>
</row>
<row>
<entry>040506</entry>
<entry>ISO-8601</entry>
</row>
<row>
<entry>04:05 AM</entry>
<entry>Same as 04:05; AM does not affect value</entry>
</row>
<row>
<entry>04:05 PM</entry>
<entry>Same as 16:05; input hour must be <= 12</entry>
</row>
<row>
<entry>z</entry>
<entry>Same as 00:00:00</entry>
</row>
<row>
<entry>zulu</entry>
<entry>Same as 00:00:00</entry>
</row>
<row>
<entry>allballs</entry>
<entry>Same as 00:00:00</entry>
</row>
</tbody>
</tgroup>
</table>
</para>
<para>
<table tocentry="1">
<title><productname>Postgres</productname> Time Zone Input</title>
<titleabbrev>Time Zone Inputs</titleabbrev>
<tgroup cols="2">
<thead>
<row>
<entry>Time Zone</entry>
<entry>Description</entry>
</row>
</thead>
<tbody>
<row>
<entry>PST</entry>
<entry>Pacific Standard Time</entry>
</row>
<row>
<entry>-8:00</entry>
<entry>ISO-8601 offset for PST</entry>
</row>
<row>
<entry>-800</entry>
<entry>ISO-8601 offset for PST</entry>
</row>
<row>
<entry>-8</entry>
<entry>ISO-8601 offset for PST</entry>
</row>
</tbody>
</tgroup>
</table>
</para>
<para>
<table tocentry="1">
<title><productname>Postgres</productname> Recognized Time Zones</title>
<titleabbrev>Time Zones</titleabbrev>
<tgroup cols="3">
<thead>
<row>
<entry>Time Zone</entry>
<entry>Offset from UTC</entry>
<entry>Description</entry>
</row>
</thead>
<tbody>
<row>
<entry>ACSST</entry>
<entry>+10:30 </entry>
<entry>Central Australia Summer Std Time</entry>
</row>
<row>
<entry>ACST</entry>
<entry>+09:30 </entry>
<entry>Central Australia Std Time</entry>
</row>
<row>
<entry>ADT</entry>
<entry>-02:00 </entry>
<entry>Atlantic Daylight Time</entry>
</row>
<row>
<entry>AESST</entry>
<entry>+11:00 </entry>
<entry>Australia Eastern Summer Std Time</entry>
</row>
<row>
<entry>AEST</entry>
<entry>+10:00 </entry>
<entry>Australia Eastern Std Time</entry>
</row>
<row>
<entry>AHST</entry>
<entry>-10:00 </entry>
<entry>Alaska-Hawaii Std Time</entry>
</row>
<row>
<entry>AST</entry>
<entry>-4:00 </entry>
<entry>Atlantic Std Time (Canada)</entry>
</row>
<row>
<entry>AWSST</entry>
<entry>+9:00 </entry>
<entry>Australia Western Summer Std Time</entry>
</row>
<row>
<entry>AWST</entry>
<entry>+8:00 </entry>
<entry>Australia Western Std Time</entry>
</row>
<row>
<entry>BST</entry>
<entry>+1:00 </entry>
<entry>British Summer Time</entry>
</row>
<row>
<entry>BT</entry>
<entry>+3:00 </entry>
<entry>Baghdad Time</entry>
</row>
<row>
<entry>CADT</entry>
<entry>+10:30 </entry>
<entry>Central Australia Daylight Savings Time</entry>
</row>
<row>
<entry>CAST</entry>
<entry>+09:30 </entry>
<entry>Central Australia Std Time</entry>
</row>
<row>
<entry>CAT</entry>
<entry>-10:00 </entry>
<entry>Central Alaska Time</entry>
</row>
<row>
<entry>CCT</entry>
<entry>+8:00 </entry>
<entry>China Coastal Time</entry>
</row>
<row>
<entry>CDT</entry>
<entry>-5:00 </entry>
<entry>Central Daylight Time</entry>
</row>
<row>
<entry>CET</entry>
<entry>+1:00 </entry>
<entry>Central European Time</entry>
</row>
<row>
<entry>CETDST</entry>
<entry>+2:00 </entry>
<entry>Central European Daylight Savings Time</entry>
</row>
<row>
<entry>CST</entry>
<entry>+6:00 </entry>
<entry>Central Std Time</entry>
</row>
<row>
<entry>DNT</entry>
<entry>+1:00 </entry>
<entry>Dansk Normal Tid</entry>
</row>
<row>
<entry>DST</entry>
<entry>+1:00 </entry>
<entry>Dansk Standard Time (?)</entry>
</row>
<row>
<entry>EAST</entry>
<entry>+10:00 </entry>
<entry>East Australian Std Time</entry>
</row>
<row>
<entry>EDT</entry>
<entry>-4:00 </entry>
<entry>Eastern Daylight Time</entry>
</row>
<row>
<entry>EET</entry>
<entry>+2:00 </entry>
<entry>Eastern Europe, USSR Zone 1</entry>
</row>
<row>
<entry>EETDST</entry>
<entry>+3:00 </entry>
<entry>Eastern Europe Daylight Savings Time</entry>
</row>
<row>
<entry>EST</entry>
<entry>-5:00 </entry>
<entry>Eastern Standard Time</entry>
</row>
<row>
<entry>FST</entry>
<entry>+1:00 </entry>
<entry>French Summer Time</entry>
</row>
<row>
<entry>FWT</entry>
<entry>+2:00</entry>
<entry>French Winter Time</entry>
</row>
<row>
<entry>GMT</entry>
<entry>0:00</entry>
<entry>Greenwish Mean Time</entry>
</row>
<row>
<entry>GST</entry>
<entry>+10:00</entry>
<entry>Guam Std Time, USSR Zone 9</entry>
</row>
<row>
<entry>HDT</entry>
<entry>-9:00</entry>
<entry>Hawaii/Alaska</entry>
</row>
<row>
<entry>IDLE</entry>
<entry>+12:00</entry>
<entry>International Date Line, East</entry>
</row>
<row>
<entry>IDLW</entry>
<entry>-12:00</entry>
<entry>International Date Line, West</entry>
</row>
<row>
<entry>IST</entry>
<entry>+2:00</entry>
<entry>Israel</entry>
</row>
<row>
<entry>IT</entry>
<entry>+3:40</entry>
<entry>Iran Time</entry>
</row>
<row>
<entry>JST</entry>
<entry>+9:00</entry>
<entry>Japan Std Time,USSR Zone 8</entry>
</row>
<row>
<entry>JT</entry>
<entry>+7:30</entry>
<entry>Java Time</entry>
</row>
<row>
<entry>KST</entry>
<entry>+9:00</entry>
<entry>Korea Standard Time</entry>
</row>
<row>
<entry>LIGT</entry>
<entry>+10:00</entry>
<entry>Melbourne, Australia</entry>
</row>
<row>
<entry>MDT</entry>
<entry>-6:00</entry>
<entry>Mountain Daylight Time</entry>
</row>
<row>
<entry>MEST</entry>
<entry>+2:00</entry>
<entry>Middle Europe Summer Time</entry>
</row>
<row>
<entry>MET</entry>
<entry>+1:00</entry>
<entry>Middle Europe Time</entry>
</row>
<row>
<entry>METDST</entry>
<entry>+2:00</entry>
<entry>Middle Europe Daylight Time</entry>
</row>
<row>
<entry>MEWT</entry>
<entry>+1:00</entry>
<entry>Middle Europe Winter Time</entry>
</row>
<row>
<entry>MEZ</entry>
<entry>+1:00</entry>
<entry>Middle Europe Zone</entry>
</row>
<row>
<entry>MST</entry>
<entry>-7:00</entry>
<entry>Mountain Standard Time</entry>
</row>
<row>
<entry>MT</entry>
<entry>+8:30</entry>
<entry>Moluccas Time</entry>
</row>
<row>
<entry>NDT</entry>
<entry>-2:30</entry>
<entry>Newfoundland Daylight Time</entry>
</row>
<row>
<entry>NFT</entry>
<entry>-3:30</entry>
<entry>Newfoundland Standard Time</entry>
</row>
<row>
<entry>NOR</entry>
<entry>+1:00</entry>
<entry>Norway Standard Time</entry>
</row>
<row>
<entry>NST</entry>
<entry>-3:30</entry>
<entry>Newfoundland Standard Time</entry>
</row>
<row>
<entry>NT</entry>
<entry>-11:00</entry>
<entry>Nome Time</entry>
</row>
<row>
<entry>NZDT</entry>
<entry>+13:00</entry>
<entry>New Zealand Daylight Time</entry>
</row>
<row>
<entry>NZST</entry>
<entry>+12:00</entry>
<entry>New Zealand Std Time</entry>
</row>
<row>
<entry>NZT</entry>
<entry>+12:00</entry>
<entry>New Zealand Time</entry>
</row>
<row>
<entry>PDT</entry>
<entry>-7:00</entry>
<entry>Pacific Daylight Time</entry>
</row>
<row>
<entry>PST</entry>
<entry>-8:00</entry>
<entry>Pacific Std Time</entry>
</row>
<row>
<entry>SADT</entry>
<entry>+10:30</entry>
<entry>South Australian Daylight Time</entry>
</row>
<row>
<entry>SAT</entry>
<entry>+9:30</entry>
<entry>South Australian Std Time</entry>
</row>
<row>
<entry>SET</entry>
<entry>+1:00</entry>
<entry>Seychelles Time</entry>
</row>
<row>
<entry>SST</entry>
<entry>+2:00</entry>
<entry>Swedish Summer Time</entry>
</row>
<row>
<entry>SWT</entry>
<entry>+1:00</entry>
<entry>Swedish Winter Time</entry>
</row>
<row>
<entry>WADT</entry>
<entry>+8:00</entry>
<entry>West Australian Daylight Time</entry>
</row>
<row>
<entry>WAST</entry>
<entry>+7:00</entry>
<entry>West Australian Std Time</entry>
</row>
<row>
<entry>WAT</entry>
<entry>-1:00</entry>
<entry>West Africa Time</entry>
</row>
<row>
<entry>WDT</entry>
<entry>+9:00</entry>
<entry>West Australian Daylight Time</entry>
</row>
<row>
<entry>WET</entry>
<entry>0:00</entry>
<entry>Western Europe</entry>
</row>
<row>
<entry>WETDST</entry>
<entry>+1:00</entry>
<entry>Western Europe Daylight Savings Time</entry>
</row>
<row>
<entry>WST</entry>
<entry>+8:00</entry>
<entry>West Australian Std Time</entry>
</row>
<row>
<entry>YDT</entry>
<entry>-8:00</entry>
<entry>Yukon Daylight Time</entry>
</row>
<row>
<entry>YST</entry>
<entry>-9:00</entry>
<entry>Yukon Standard Time</entry>
</row>
<row>
<entry>ZP4</entry>
<entry>-4:00</entry>
<entry>GMT +4 hours</entry>
</row>
<row>
<entry>ZP5</entry>
<entry>-5:00</entry>
<entry>GMT +5 hours</entry>
</row>
<row>
<entry>ZP6</entry>
<entry>-6:00</entry>
<entry>GMT +6 hours</entry>
</row>
</tbody>
</tgroup>
</table>
<note>
<para>
If the compiler option USE_AUSTRALIAN_RULES is set
then <literal>EST</literal> refers to Australia Eastern Std Time,
which has an offset of +10:00 hours from UTC.
</para>
<para>
It is interesting that Australian time zones and their naming variants
account for fully one quarter of all time zones in the
<productname>Postgres</productname> time zone lookup table.
</para>
</note>
</para>
<procedure>
<title>Date/Time Input Interpretation</title>
<step>
<para>
Break the input string into tokens and categorize each token as
a string, time, time zone, or number.
</para>
<substeps>
<step>
<para>
If the token contains a colon (":"), this is a time string.
</para>
</step>
<step>
<para>
If the token contains a dash ("-"), slash ("/"), or dot ("."),
this is a date string which may have a text month.
</para>
</step>
<step>
<para>
If the token is numeric only, then it is either a single field
or an ISO-8601 concatenated date (e.g. "19990113" for January 13, 1999)
or time (e.g. 141516 for 14:15:16).
</para>
</step>
<step>
<para>
If the token starts with a plus ("+") or minus ("-"),
then it is either a time zone or a special field.
</para>
</step>
</substeps>
</step>
<step>
<para>
If the token is a text string, match up with possible strings.
</para>
<substeps>
<step>
<para>
Do a binary-search table lookup for the token
as either a special string (e.g. <literal>today</literal>),
day (e.g. <literal>Thursday</literal>),
month (e.g. <literal>January</literal>), or noise word (e.g. <literal>on</literal>).
</para>
<para>
Set field values and bit mask for fields.
For example, set year, month, day for <literal>today</literal>, and additionally
hour, minute, second for <literal>now</literal>.
</para>
</step>
<step>
<para>
If not found, do a similar binary-search table lookup to match
the token with a time zone.
</para>
</step>
<step>
<para>
If not found, throw an error.
</para>
</step>
</substeps>
</step>
<step>
<para>
The token is a number or number field. If there are more than 4 digits,
and if no other date fields have been previously read, then interpret
as a "concatenated date".
</para>
<substeps>
<step>
<para>If there </para>
</step>
</substeps>
</step>
<step>
<para>
</para>
</step>
<step>
<para>
</para>
</step>
<step>
<para>
</para>
</step>
<step>
<para>
</para>
</step>
<step>
<para>
</para>
</step>
</procedure>
</sect2> </sect2>
<sect2> <sect2>
......
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