Обсуждение: timestamptz alias
Hi, I'm happy that the rather verbose "timestamp with time zone" has the much nicer alias "timestamptz", however it seems that this alias is not documented, neither at http://developer.postgresql.org/pgdocs/postgres/datatype-datetime.html nor at http://www.postgresql.org/docs/8.1/interactive/datatype-datetime.html I see it mentioned at http://www.postgresql.org/docs/8.1/interactive/datatype.html but that's possibly not where people look at first, when they search for the timestamp type. (At least I found it only when grepping for "timestamptz" in the docs. :-) Should the alias be mentioned on the datetime page? The same for timetz? What do you think? Thanks, Markus
On Oct 2, 2006, at 18:15 , Markus Schaber wrote: > Hi, > > I'm happy that the rather verbose "timestamp with time zone" has the > much nicer alias "timestamptz", however it seems that this alias is > not > documented, neither at > http://developer.postgresql.org/pgdocs/postgres/datatype-datetime.html > nor at http://www.postgresql.org/docs/8.1/interactive/datatype- > datetime.html > > I see it mentioned at > http://www.postgresql.org/docs/8.1/interactive/datatype.html but > that's > possibly not where people look at first, when they search for the > timestamp type. (At least I found it only when grepping for > "timestamptz" in the docs. :-) > > Should the alias be mentioned on the datetime page? The same for > timetz? > What do you think? I am pleased that the documentation promotes database-independent ("standard") SQL. -M
On Oct 2, 2006, at 6:22 PM, AgentM wrote: > On Oct 2, 2006, at 18:15 , Markus Schaber wrote: >> I'm happy that the rather verbose "timestamp with time zone" has the >> much nicer alias "timestamptz", however it seems that this alias >> is not >> documented, neither at >> http://developer.postgresql.org/pgdocs/postgres/datatype- >> datetime.html >> nor at http://www.postgresql.org/docs/8.1/interactive/datatype- >> datetime.html >> >> I see it mentioned at >> http://www.postgresql.org/docs/8.1/interactive/datatype.html but >> that's >> possibly not where people look at first, when they search for the >> timestamp type. (At least I found it only when grepping for >> "timestamptz" in the docs. :-) >> >> Should the alias be mentioned on the datetime page? The same for >> timetz? >> What do you think? > > I am pleased that the documentation promotes database-independent > ("standard") SQL. There's a difference between promoting and withholding info. I'd rather see us explicitly state which is preferred and why. BTW, another confusing example is all the string functions that are essentially the same, such as substring and substr. (http:// www.postgresql.org/docs/8.1/interactive/functions-string.html) -- Jim Nasby jim@nasby.net EnterpriseDB http://enterprisedb.com 512.569.9461 (cell)
Hi, Jim, Jim Nasby wrote: > There's a difference between promoting and withholding info. I'd rather > see us explicitly state which is preferred and why. Here's a small patch that adds an appropriate explanation. Index: doc/src/sgml/datatype.sgml =================================================================== RCS file: /projects/cvsroot/pgsql/doc/src/sgml/datatype.sgml,v retrieving revision 1.176 diff -u -r1.176 datatype.sgml --- doc/src/sgml/datatype.sgml 22 Sep 2006 16:20:00 -0000 1.176 +++ doc/src/sgml/datatype.sgml 3 Oct 2006 09:14:32 -0000 @@ -1372,6 +1372,17 @@ </para> </note> + <note> + <para> + <productname>PostgreSQL</productname> also supports the aliases + <type>timestamptz</type> for <type>timestamp with time zone</type> + and <type>timetz</type> for <type>time with time zone</type>. It + is recommended to avoid them, as the more verbose variants comply + to the SQL standard, and thus are more portable. But there are no + plans to drop the short aliases in future versions. + </para> + </note> + <para> <type>time</type>, <type>timestamp</type>, and <type>interval</type> accept an optional precision value HTH, Markus -- Markus Schaber | Logical Tracking&Tracing International AG Dipl. Inf. | Software Development GIS Fight against software patents in Europe! www.ffii.org www.nosoftwarepatents.org
Markus Schaber <schabi@logix-tt.com> writes:
> Here's a small patch that adds an appropriate explanation.
If we're going to document these aliases, what of float4, float8, and bool?
Also, although the docs mention int2/int4/int8, it's more or less left
to the reader's imagination to deduce what they are.
Perhaps it'd be better to provide a small table of recognized type
aliases, rather than inserting equivalent notes into three or four places.
regards, tom lane
Tom Lane wrote: > Markus Schaber <schabi@logix-tt.com> writes: > >> Here's a small patch that adds an appropriate explanation. >> > > If we're going to document these aliases, what of float4, float8, and bool? > Also, although the docs mention int2/int4/int8, it's more or less left > to the reader's imagination to deduce what they are. > > Perhaps it'd be better to provide a small table of recognized type > aliases, rather than inserting equivalent notes into three or four places. > > you mean like the table here? http://momjian.us/main/writings/pgsql/sgml/datatype.html cheers andrew
Moving to -docs On Tue, Oct 03, 2006 at 12:13:46PM -0400, Andrew Dunstan wrote: > Tom Lane wrote: > >Markus Schaber <schabi@logix-tt.com> writes: > > > >>Here's a small patch that adds an appropriate explanation. > >> > > > >If we're going to document these aliases, what of float4, float8, and bool? > >Also, although the docs mention int2/int4/int8, it's more or less left > >to the reader's imagination to deduce what they are. > > > >Perhaps it'd be better to provide a small table of recognized type > >aliases, rather than inserting equivalent notes into three or four places. > > > > > > > you mean like the table here? > http://momjian.us/main/writings/pgsql/sgml/datatype.html An issue I've seen with the docs is that for chapters that have a lot of sections (such as 8), the section list at the start of each chapter fills the screen, so it's easy to miss the fact that there's more info beneath the list (which is wy presumably most folks never knew that table existed). I think the ideal way to handle this would be to put the table of contents in a side-bar and flow the text around it. But that could be a real bear to do in docbook/sgml, so perhaps it would be better to just force the TOC for each chapter onto it's own page (and ensure the overview/introduction text shows up in the TOC). -- Jim Nasby jim@nasby.net EnterpriseDB http://enterprisedb.com 512.569.9461 (cell)
Hi, Tom, Tom Lane wrote: >> Here's a small patch that adds an appropriate explanation. > > If we're going to document these aliases, what of float4, float8, and bool? > Also, although the docs mention int2/int4/int8, it's more or less left > to the reader's imagination to deduce what they are. > > Perhaps it'd be better to provide a small table of recognized type > aliases, rather than inserting equivalent notes into three or four places. It's not only about documenting the pure existence of the aliases (which was already documented in the table on the datatype TOC page), it's also about telling the user which of the names are the ones to avoid, and the reasons to do so. HTH, Markus -- Markus Schaber | Logical Tracking&Tracing International AG Dipl. Inf. | Software Development GIS Fight against software patents in Europe! www.ffii.org www.nosoftwarepatents.org
Markus Schaber wrote: > It's not only about documenting the pure existence of the aliases (which > was already documented in the table on the datatype TOC page), it's also > about telling the user which of the names are the ones to avoid, and the > reasons to do so. > > > *blink* Why do any need to be avoided? What you use is a matter of taste, and your organisation's coding standards. From a purely technical POV I don't see any reason to avoid using either the canonical type names or the various aliases. cheers andrew
Hi, Andrew, Andrew Dunstan wrote: >> It's not only about documenting the pure existence of the aliases (which >> was already documented in the table on the datatype TOC page), it's also >> about telling the user which of the names are the ones to avoid, and the >> reasons to do so. > > *blink* Why do any need to be avoided? What you use is a matter of > taste, and your organisation's coding standards. From a purely technical > POV I don't see any reason to avoid using either the canonical type > names or the various aliases. At least compatibility with the SQL standard, as well as with other Databases might be a reason. Using pure "timestamp" may lead human readers to be confused, because it has both meanings with and without timezone historically, this might be a reason to prefer the "timestamp with[out] time zone" wording. HTH, Markus -- Markus Schaber | Logical Tracking&Tracing International AG Dipl. Inf. | Software Development GIS Fight against software patents in Europe! www.ffii.org www.nosoftwarepatents.org
On Oct 4, 2006, at 10:52 AM, Markus Schaber wrote: > Andrew Dunstan wrote: >>> It's not only about documenting the pure existence of the aliases >>> (which >>> was already documented in the table on the datatype TOC page), >>> it's also >>> about telling the user which of the names are the ones to avoid, >>> and the >>> reasons to do so. >> >> *blink* Why do any need to be avoided? What you use is a matter of >> taste, and your organisation's coding standards. From a purely >> technical >> POV I don't see any reason to avoid using either the canonical type >> names or the various aliases. > > At least compatibility with the SQL standard, as well as with other > Databases might be a reason. It would be nice to denote types/aliases that are and aren't ANSI. A number are marked in the docs, but it would be good to add the info to that summary table. -- Jim Nasby jim@nasby.net EnterpriseDB http://enterprisedb.com 512.569.9461 (cell) -- Jim Nasby jimn@enterprisedb.com EnterpriseDB http://enterprisedb.com 512.569.9461 (cell)
Jim Nasby wrote: > > It would be nice to denote types/aliases that are and aren't ANSI. A > number are marked in the docs, but it would be good to add the info > to that summary table. Right under the table this sentence appears: Compatibility: The following types (or spellings thereof) are specified by SQL: bit, bit varying, boolean, char, character varying, character, varchar, date, double precision, integer, interval, numeric, decimal, real, smallint, time (with or without time zone), timestamp (with or without time zone). What's unclear about that? cheers andrew
On Fri, Oct 06, 2006 at 02:35:55AM -0500, Andrew Dunstan wrote: > Jim Nasby wrote: > > > > It would be nice to denote types/aliases that are and aren't ANSI. A > > number are marked in the docs, but it would be good to add the info > > to that summary table. > > Right under the table this sentence appears: > > Compatibility: The following types (or spellings thereof) are specified > by SQL: bit, bit varying, boolean, char, character varying, character, > varchar, date, double precision, integer, interval, numeric, decimal, > real, smallint, time (with or without time zone), timestamp (with or > without time zone). > > What's unclear about that? Oops. This is what happens when I answer emails on a plane. :( -- Jim Nasby jim@nasby.net EnterpriseDB http://enterprisedb.com 512.569.9461 (cell)