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Trigger function for inserting user names.

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Install compiled functions into $(LIBDIR)/contrib.
(Thanks to Brook Milligan <brook@trillium.NMSU.Edu>)
This commit is contained in:
Vadim B. Mikheev
1997-10-17 09:55:34 +00:00
parent 962c8bd66d
commit 629e895101
5 changed files with 129 additions and 2 deletions
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77
contrib/spi/insert_username.c Normal file
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/*
* insert_username.c
* $Modified: Thu Oct 16 08:13:42 1997 by brook $
*
* insert user name in response to a trigger
* usage: insert_username (column_name)
*/
#include "executor/spi.h" /* this is what you need to work with SPI */
#include "commands/trigger.h" /* -"- and triggers */
#include "miscadmin.h" /* for GetPgUserName() */
HeapTuple insert_username (void);
HeapTuple
insert_username ()
{
Trigger *trigger; /* to get trigger name */
int nargs; /* # of arguments */
Datum newval; /* new value of column */
char **args; /* arguments */
char *relname; /* triggered relation name */
Relation rel; /* triggered relation */
HeapTuple rettuple = NULL;
TupleDesc tupdesc; /* tuple description */
int attnum;
/* sanity checks from autoinc.c */
if (!CurrentTriggerData)
elog(WARN, "insert_username: triggers are not initialized");
if (TRIGGER_FIRED_FOR_STATEMENT(CurrentTriggerData->tg_event))
elog(WARN, "insert_username: can't process STATEMENT events");
if (TRIGGER_FIRED_AFTER(CurrentTriggerData->tg_event))
elog(WARN, "insert_username: must be fired before event");
if (TRIGGER_FIRED_BY_INSERT(CurrentTriggerData->tg_event))
rettuple = CurrentTriggerData->tg_trigtuple;
else if (TRIGGER_FIRED_BY_UPDATE(CurrentTriggerData->tg_event))
rettuple = CurrentTriggerData->tg_newtuple;
else
elog(WARN, "insert_username: can't process DELETE events");
rel = CurrentTriggerData->tg_relation;
relname = SPI_getrelname(rel);
trigger = CurrentTriggerData->tg_trigger;
nargs = trigger->tgnargs;
if (nargs != 1)
elog(WARN, "insert_username (%s): one argument was expected", relname);
args = trigger->tgargs;
tupdesc = rel->rd_att;
CurrentTriggerData = NULL;
attnum = SPI_fnumber (tupdesc, args[0]);
if ( attnum < 0 )
elog(WARN, "insert_username (%s): there is no attribute %s", relname, args[0]);
if (SPI_gettypeid (tupdesc, attnum) != TEXTOID)
elog(WARN, "insert_username (%s): attribute %s must be of TEXT type",
relname, args[0]);
/* create fields containing name */
newval = PointerGetDatum (textin (GetPgUserName ()));
/* construct new tuple */
rettuple = SPI_modifytuple (rel, rettuple, 1, &attnum, &newval, NULL);
if ( rettuple == NULL )
elog (WARN, "insert_username (%s): %d returned by SPI_modifytuple",
relname, SPI_result);
pfree (relname);
return (rettuple);
}