11.\" This is -*-nroff-*-
22.\" XXX standard disclaimer belongs here....
3- .\" $Header: /cvsroot/pgsql/src/man/Attic/sql.l,v 1.6 1997/10/01 18:53:29 momjian Exp $
3+ .\" $Header: /cvsroot/pgsql/src/man/Attic/sql.l,v 1.7 1997/11/03 04:47:08 momjian Exp $
44.TH INTRODUCTION SQL 11/5/95 PostgreSQL PostgreSQL
55.SH "Section 4\(em SQL Commands (COMMANDS)"
66.SH "General Information"
132132is either an attribute of a given class or one of the following:
133133.nf
134134oid
135- tmin
136- tmax
137135xmin
138136xmax
139137cmin
@@ -145,19 +143,16 @@ stands for the unique identifier of an instance which is added by
145143Postgres to all instances automatically. Oids are not reused and are 32
146144bit quantities.
147145.PP
148- .IR " Tmin, tmax, xmin , cmin, xmax"
146+ .IR " Xmin , cmin, xmax"
149147and
150148.IR cmax
151- stand respectively for the time that the instance was inserted, the
152- time the instance was deleted, the identity of the inserting
149+ stand respectively for the identity of the inserting
153150transaction, the command identifier within the transaction, the
154151identity of the deleting transaction and its associated deleting
155152command. For further information on these fields consult [STON87].
156153Times are represented internally as instances of the\*( lq \*( rq
157- data type. Transaction identifiers are 32 bit quantities which are
158- assigned sequentially starting at 512. Command identifiers are 16 bit
159- objects; hence, it is an error to have more than 65535 SQL commands
160- within one transaction.
154+ data type. Transaction and command identifiers are 32 bit quantities.
155+ Transactions are assigned sequentially starting at 512.
161156.SH "Columns"
162157A
163158.IR column
@@ -301,53 +296,17 @@ where
301296.IR class_reference
302297is of the form
303298.nf
304- class_name [time_expression] [ *]
299+ class_name [*]
305300.fi
306301The
307302.IR " from expression"
308303defines one or more instance variables to range over the class
309304indicated in
310305.IR class_reference .
311- Adding a
312- .IR time_expression
313- will indicate that a historical class is desired. One can also request
306+ One can also request
314307the instance variable to range over all classes that are beneath the
315308indicated class in the inheritance hierarchy by postpending the
316309designator\*( lq \*( rq
317- .SH " Time Expressions"
318- A
319- .IR " time expression"
320- is in one of two forms:
321- .nf
322- ["date"]
323- ["date-1", "date-2"]
324- .fi
325- The first case requires instances that are valid at the indicated
326- time. The second case requires instances that are valid at some time
327- within the date range specified. If no time expression is indicated,
328- the default is\*( lq \*( rq
329- .PP
330- In each case, the date is a character string of the form
331- .nf
332- "[MON-FRI] MMM DD [HH:MM:SS] YYYY [Timezone]"
333- .fi
334- where MMM is the month (Jan\- Dec), DD is a legal day number in the
335- specified month, HH:MM:SS is an optional time in that day (24-hour
336- clock), and YYYY is the year. If the time of day HH:MM:SS is not
337- specified, it defaults to midnight at the start of the specified day.
338- As of Version 3.0, times are no longer read and written using
339- Greenwich Mean Time; the input and output routines default to the
340- local time zone.
341- .PP
342- For example,
343- .nf
344- ["Jan 1 1990"]
345- ["Mar 3 00:00:00 1980", "Mar 3 23:59:59 1981"]
346- .fi
347- are valid time specifications.
348- .PP
349- Note that this syntax is slightly different than that used by the
350- time-range type.
351310.SH "SEE ALSO"
352311insert(l),
353312delete(l),