Remove time travel from manuals.

This commit is contained in:
Bruce Momjian 1997-11-03 04:47:08 +00:00
parent 475a8873b0
commit 7589967613
1 changed files with 7 additions and 48 deletions

View File

@ -1,6 +1,6 @@
.\" This is -*-nroff-*- .\" This is -*-nroff-*-
.\" XXX standard disclaimer belongs here.... .\" XXX standard disclaimer belongs here....
.\" $Header: /cvsroot/pgsql/src/man/Attic/sql.l,v 1.6 1997/10/01 18:53:29 momjian Exp $ .\" $Header: /cvsroot/pgsql/src/man/Attic/sql.l,v 1.7 1997/11/03 04:47:08 momjian Exp $
.TH INTRODUCTION SQL 11/5/95 PostgreSQL PostgreSQL .TH INTRODUCTION SQL 11/5/95 PostgreSQL PostgreSQL
.SH "Section 4 \(em SQL Commands (COMMANDS)" .SH "Section 4 \(em SQL Commands (COMMANDS)"
.SH "General Information" .SH "General Information"
@ -132,8 +132,6 @@ A
is either an attribute of a given class or one of the following: is either an attribute of a given class or one of the following:
.nf .nf
oid oid
tmin
tmax
xmin xmin
xmax xmax
cmin cmin
@ -145,19 +143,16 @@ stands for the unique identifier of an instance which is added by
Postgres to all instances automatically. Oids are not reused and are 32 Postgres to all instances automatically. Oids are not reused and are 32
bit quantities. bit quantities.
.PP .PP
.IR "Tmin, tmax, xmin, cmin, xmax" .IR "Xmin, cmin, xmax"
and and
.IR cmax .IR cmax
stand respectively for the time that the instance was inserted, the stand respectively for the identity of the inserting
time the instance was deleted, the identity of the inserting
transaction, the command identifier within the transaction, the transaction, the command identifier within the transaction, the
identity of the deleting transaction and its associated deleting identity of the deleting transaction and its associated deleting
command. For further information on these fields consult [STON87]. command. For further information on these fields consult [STON87].
Times are represented internally as instances of the \*(lqabstime\*(rq Times are represented internally as instances of the \*(lqabstime\*(rq
data type. Transaction identifiers are 32 bit quantities which are data type. Transaction and command identifiers are 32 bit quantities.
assigned sequentially starting at 512. Command identifiers are 16 bit Transactions are assigned sequentially starting at 512.
objects; hence, it is an error to have more than 65535 SQL commands
within one transaction.
.SH "Columns" .SH "Columns"
A A
.IR column .IR column
@ -301,53 +296,17 @@ where
.IR class_reference .IR class_reference
is of the form is of the form
.nf .nf
class_name [time_expression] [*] class_name [*]
.fi .fi
The The
.IR "from expression" .IR "from expression"
defines one or more instance variables to range over the class defines one or more instance variables to range over the class
indicated in indicated in
.IR class_reference . .IR class_reference .
Adding a One can also request
.IR time_expression
will indicate that a historical class is desired. One can also request
the instance variable to range over all classes that are beneath the the instance variable to range over all classes that are beneath the
indicated class in the inheritance hierarchy by postpending the indicated class in the inheritance hierarchy by postpending the
designator \*(lq*\*(rq. designator \*(lq*\*(rq.
.SH "Time Expressions"
A
.IR "time expression"
is in one of two forms:
.nf
["date"]
["date-1", "date-2"]
.fi
The first case requires instances that are valid at the indicated
time. The second case requires instances that are valid at some time
within the date range specified. If no time expression is indicated,
the default is \*(lqnow\*(rq.
.PP
In each case, the date is a character string of the form
.nf
"[MON-FRI] MMM DD [HH:MM:SS] YYYY [Timezone]"
.fi
where MMM is the month (Jan \- Dec), DD is a legal day number in the
specified month, HH:MM:SS is an optional time in that day (24-hour
clock), and YYYY is the year. If the time of day HH:MM:SS is not
specified, it defaults to midnight at the start of the specified day.
As of Version 3.0, times are no longer read and written using
Greenwich Mean Time; the input and output routines default to the
local time zone.
.PP
For example,
.nf
["Jan 1 1990"]
["Mar 3 00:00:00 1980", "Mar 3 23:59:59 1981"]
.fi
are valid time specifications.
.PP
Note that this syntax is slightly different than that used by the
time-range type.
.SH "SEE ALSO" .SH "SEE ALSO"
insert(l), insert(l),
delete(l), delete(l),