postgresql/contrib/spi
Bruce Momjian a12b4e279b I checked all the previous string handling errors and most of them were
already fixed by You. However there were a few left and attached patch
should fix the rest of them.

I used StringInfo only in 2 places and both of them are inside debug
ifdefs. Only performance penalty will come from using strlen() like all
the other code does.

I also modified some of the already patched parts by changing
snprintf(buf, 2 * BUFSIZE, ... style lines to
snprintf(buf, sizeof(buf), ... where buf is an array.

Jukka Holappa
2002-09-02 06:11:43 +00:00
..
preprocessor Ensure that all uses of <ctype.h> functions are applied to unsigned-char 2000-12-03 20:45:40 +00:00
autoinc.c Sequences are now based on int8, not int4, arithmetic. SERIAL pseudo-type 2001-08-16 20:38:56 +00:00
autoinc.example General function for SERIAL/IDENTITY/AUTOINCREMENT feature. 1997-10-02 18:01:57 +00:00
autoinc.sql.in Add a bunch of pseudo-types to replace the behavior formerly associated 2002-08-22 00:01:51 +00:00
insert_username.c pgindent run. Make it all clean. 2001-03-22 04:01:46 +00:00
insert_username.example Trigger function for inserting user names. 1997-10-17 09:55:34 +00:00
insert_username.sql.in Add a bunch of pseudo-types to replace the behavior formerly associated 2002-08-22 00:01:51 +00:00
Makefile To fix the perpetually broken makefiles in the contrib tree, I have 2001-09-06 10:49:30 +00:00
moddatetime.c pgindent run. Make it all clean. 2001-03-22 04:01:46 +00:00
moddatetime.example Remove the last traces of datatypes datetime and timespan. 2002-05-03 04:11:08 +00:00
moddatetime.sql.in Add a bunch of pseudo-types to replace the behavior formerly associated 2002-08-22 00:01:51 +00:00
README.spi Add missing /contrib files 2000-06-19 14:02:16 +00:00
refint.c I checked all the previous string handling errors and most of them were 2002-09-02 06:11:43 +00:00
refint.example README for refint.c and example of using. 1997-09-12 02:41:15 +00:00
refint.sql.in Add a bunch of pseudo-types to replace the behavior formerly associated 2002-08-22 00:01:51 +00:00
timetravel.c I checked all the previous string handling errors and most of them were 2002-09-02 06:11:43 +00:00
timetravel.example Remove the last traces of datatypes datetime and timespan. 2002-05-03 04:11:08 +00:00
timetravel.sql.in Add a bunch of pseudo-types to replace the behavior formerly associated 2002-08-22 00:01:51 +00:00

Here are general trigger functions provided as workable examples
of using SPI and triggers. "General" means that functions may be
used for defining triggers for any tables but you have to specify
table/field names (as described below) while creating a trigger.

1. refint.c - functions for implementing referential integrity.

check_primary_key () is to used for foreign keys of a table.
   
   You are to create trigger (BEFORE INSERT OR UPDATE) using this 
function on a table referencing another table. You are to specify
as function arguments: triggered table column names which correspond
to foreign key, referenced table name and column names in referenced
table which correspond to primary/unique key.
   You may create as many triggers as you need - one trigger for
one reference.

check_foreign_key () is to used for primary/unique keys of a table.

   You are to create trigger (BEFORE DELETE OR UPDATE) using this
function on a table referenced by another table(s). You are to specify
as function arguments: number of references for which function has to
performe checking, action if referencing key found ('cascade' - to delete
corresponding foreign key, 'restrict' - to abort transaction if foreign keys 
exist, 'setnull' - to set foreign key referencing primary/unique key
being deleted to null), triggered table column names which correspond
to primary/unique key, referencing table name and column names corresponding
to foreign key (, ... - as many referencing tables/keys as specified
by first argument).
   Note, that NOT NULL constraint and unique index have to be defined by
youself.

   There are examples in refint.example and regression tests
(sql/triggers.sql).

   To CREATE FUNCTIONs use refint.sql (will be made by gmake from
refint.source).


2. timetravel.c - functions for implementing time travel feature.

   Old internally supported time-travel (TT) used insert/delete
transaction commit times. To get the same feature using triggers
you are to add to a table two columns of abstime type to store
date when a tuple was inserted (start_date) and changed/deleted 
(stop_date):

CREATE TABLE XXX (
	...		...
	date_on		abstime default currabstime(),
	date_off	abstime default 'infinity'
	...		...
);

- so, tuples being inserted with NULLs in date_on/date_off will get
_current_date_ in date_on (name of start_date column in XXX) and INFINITY in
date_off (name of stop_date column in XXX).

   Tuples with stop_date equal INFINITY are "valid now": when trigger will
be fired for UPDATE/DELETE of a tuple with stop_date NOT equal INFINITY then
this tuple will not be changed/deleted!

   If stop_date equal INFINITY then on

UPDATE: only stop_date in tuple being updated will be changed to current
date and new tuple with new data (coming from SET ... in UPDATE) will be
inserted. Start_date in this new tuple will be setted to current date and
stop_date - to INFINITY.

DELETE: new tuple will be inserted with stop_date setted to current date
(and with the same data in other columns as in tuple being deleted).

   NOTE:
1. To get tuples "valid now" you are to add _stop_date_ = 'infinity'
   to WHERE. Internally supported TT allowed to avoid this...
   Fixed rewriting RULEs could help here...
   As work arround you may use VIEWs...
2. You can't change start/stop date columns with UPDATE! 
   Use set_timetravel (below) if you need in this.

   FUNCTIONs:

timetravel() is general trigger function.

   You are to create trigger BEFORE (!!!) UPDATE OR DELETE using this
function on a time-traveled table. You are to specify two arguments: name of
start_date column and name of stop_date column in triggered table.

currabstime() may be used in DEFAULT for start_date column to get
current date.

set_timetravel() allows you turn time-travel ON/OFF for a table:

   set_timetravel('XXX', 1) will turn TT ON for table XXX (and report
old status).
   set_timetravel('XXX', 0) will turn TT OFF for table XXX (-"-).

Turning TT OFF allows you do with a table ALL what you want.

   There is example in timetravel.example.

   To CREATE FUNCTIONs use timetravel.sql (will be made by gmake from
timetravel.source).