mirror of
https://github.com/postgres/postgres.git
synced 2025-11-03 09:13:20 +03:00
101 lines
2.7 KiB
C
101 lines
2.7 KiB
C
|
|
#include "executor/spi.h" /* this is what you need to work with SPI */
|
|
#include "commands/trigger.h" /* -"- and triggers */
|
|
|
|
HeapTuple autoinc(void);
|
|
|
|
extern int4 nextval(struct varlena * seqin);
|
|
|
|
HeapTuple
|
|
autoinc()
|
|
{
|
|
Trigger *trigger; /* to get trigger name */
|
|
int nargs; /* # of arguments */
|
|
int *chattrs; /* attnums of attributes to change */
|
|
int chnattrs = 0; /* # of above */
|
|
Datum *newvals; /* vals of above */
|
|
char **args; /* arguments */
|
|
char *relname; /* triggered relation name */
|
|
Relation rel; /* triggered relation */
|
|
HeapTuple rettuple = NULL;
|
|
TupleDesc tupdesc; /* tuple description */
|
|
bool isnull;
|
|
int i;
|
|
|
|
if (!CurrentTriggerData)
|
|
elog(ERROR, "autoinc: triggers are not initialized");
|
|
if (TRIGGER_FIRED_FOR_STATEMENT(CurrentTriggerData->tg_event))
|
|
elog(ERROR, "autoinc: can't process STATEMENT events");
|
|
if (TRIGGER_FIRED_AFTER(CurrentTriggerData->tg_event))
|
|
elog(ERROR, "autoinc: 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(ERROR, "autoinc: can't process DELETE events");
|
|
|
|
rel = CurrentTriggerData->tg_relation;
|
|
relname = SPI_getrelname(rel);
|
|
|
|
trigger = CurrentTriggerData->tg_trigger;
|
|
|
|
nargs = trigger->tgnargs;
|
|
if (nargs <= 0 || nargs % 2 != 0)
|
|
elog(ERROR, "autoinc (%s): even number gt 0 of arguments was expected", relname);
|
|
|
|
args = trigger->tgargs;
|
|
tupdesc = rel->rd_att;
|
|
|
|
CurrentTriggerData = NULL;
|
|
|
|
chattrs = (int *) palloc (nargs/2 * sizeof (int));
|
|
newvals = (Datum *) palloc (nargs/2 * sizeof (Datum));
|
|
|
|
for (i = 0; i < nargs; )
|
|
{
|
|
struct varlena *seqname;
|
|
int attnum = SPI_fnumber (tupdesc, args[i]);
|
|
int32 val;
|
|
|
|
if ( attnum < 0 )
|
|
elog(ERROR, "autoinc (%s): there is no attribute %s", relname, args[i]);
|
|
if (SPI_gettypeid (tupdesc, attnum) != INT4OID)
|
|
elog(ERROR, "autoinc (%s): attribute %s must be of INT4 type",
|
|
relname, args[i]);
|
|
|
|
val = DatumGetInt32 (SPI_getbinval (rettuple, tupdesc, attnum, &isnull));
|
|
|
|
if (!isnull && val != 0)
|
|
{
|
|
i += 2;
|
|
continue;
|
|
}
|
|
|
|
i++;
|
|
chattrs[chnattrs] = attnum;
|
|
seqname = textin (args[i]);
|
|
newvals[chnattrs] = Int32GetDatum (nextval (seqname));
|
|
if ( DatumGetInt32 (newvals[chnattrs]) == 0 )
|
|
newvals[chnattrs] = Int32GetDatum (nextval (seqname));
|
|
pfree (seqname);
|
|
chnattrs++;
|
|
i++;
|
|
}
|
|
|
|
if (chnattrs > 0)
|
|
{
|
|
rettuple = SPI_modifytuple (rel, rettuple, chnattrs, chattrs, newvals, NULL);
|
|
if ( rettuple == NULL )
|
|
elog (ERROR, "autoinc (%s): %d returned by SPI_modifytuple",
|
|
relname, SPI_result);
|
|
}
|
|
|
|
pfree (relname);
|
|
pfree (chattrs);
|
|
pfree (newvals);
|
|
|
|
return (rettuple);
|
|
}
|