mirror of
https://git.postgresql.org/git/postgresql.git
synced 2024-12-27 08:39:28 +08:00
a7801b62f2
As per my recent proposal, this refactors things so that these typedefs and macros are available in a header that can be included in frontend-ish code. I also changed various headers that were undesirably including utils/timestamp.h to include datatype/timestamp.h instead. Unsurprisingly, this showed that half the system was getting utils/timestamp.h by way of xlog.h. No actual code changes here, just header refactoring.
140 lines
4.0 KiB
C
140 lines
4.0 KiB
C
/*
|
|
moddatetime.c
|
|
|
|
contrib/spi/moddatetime.c
|
|
|
|
What is this?
|
|
It is a function to be called from a trigger for the purpose of updating
|
|
a modification datetime stamp in a record when that record is UPDATEd.
|
|
|
|
Credits
|
|
This is 95%+ based on autoinc.c, which I used as a starting point as I do
|
|
not really know what I am doing. I also had help from
|
|
Jan Wieck <jwieck@debis.com> who told me about the timestamp_in("now") function.
|
|
OH, me, I'm Terry Mackintosh <terry@terrym.com>
|
|
*/
|
|
#include "postgres.h"
|
|
|
|
#include "catalog/pg_type.h"
|
|
#include "executor/spi.h"
|
|
#include "commands/trigger.h"
|
|
#include "utils/rel.h"
|
|
#include "utils/timestamp.h"
|
|
|
|
PG_MODULE_MAGIC;
|
|
|
|
extern Datum moddatetime(PG_FUNCTION_ARGS);
|
|
|
|
PG_FUNCTION_INFO_V1(moddatetime);
|
|
|
|
Datum
|
|
moddatetime(PG_FUNCTION_ARGS)
|
|
{
|
|
TriggerData *trigdata = (TriggerData *) fcinfo->context;
|
|
Trigger *trigger; /* to get trigger name */
|
|
int nargs; /* # of arguments */
|
|
int attnum; /* positional number of field to change */
|
|
Oid atttypid; /* type OID of field to change */
|
|
Datum newdt; /* The current datetime. */
|
|
char **args; /* arguments */
|
|
char *relname; /* triggered relation name */
|
|
Relation rel; /* triggered relation */
|
|
HeapTuple rettuple = NULL;
|
|
TupleDesc tupdesc; /* tuple description */
|
|
|
|
if (!CALLED_AS_TRIGGER(fcinfo))
|
|
/* internal error */
|
|
elog(ERROR, "moddatetime: not fired by trigger manager");
|
|
|
|
if (!TRIGGER_FIRED_FOR_ROW(trigdata->tg_event))
|
|
/* internal error */
|
|
elog(ERROR, "moddatetime: must be fired for row");
|
|
|
|
if (!TRIGGER_FIRED_BEFORE(trigdata->tg_event))
|
|
/* internal error */
|
|
elog(ERROR, "moddatetime: must be fired before event");
|
|
|
|
if (TRIGGER_FIRED_BY_INSERT(trigdata->tg_event))
|
|
/* internal error */
|
|
elog(ERROR, "moddatetime: cannot process INSERT events");
|
|
else if (TRIGGER_FIRED_BY_UPDATE(trigdata->tg_event))
|
|
rettuple = trigdata->tg_newtuple;
|
|
else
|
|
/* internal error */
|
|
elog(ERROR, "moddatetime: cannot process DELETE events");
|
|
|
|
rel = trigdata->tg_relation;
|
|
relname = SPI_getrelname(rel);
|
|
|
|
trigger = trigdata->tg_trigger;
|
|
|
|
nargs = trigger->tgnargs;
|
|
|
|
if (nargs != 1)
|
|
/* internal error */
|
|
elog(ERROR, "moddatetime (%s): A single argument was expected", relname);
|
|
|
|
args = trigger->tgargs;
|
|
/* must be the field layout? */
|
|
tupdesc = rel->rd_att;
|
|
|
|
/*
|
|
* This gets the position in the tuple of the field we want. args[0] being
|
|
* the name of the field to update, as passed in from the trigger.
|
|
*/
|
|
attnum = SPI_fnumber(tupdesc, args[0]);
|
|
|
|
/*
|
|
* This is where we check to see if the field we are supposed to update
|
|
* even exists. The above function must return -1 if name not found?
|
|
*/
|
|
if (attnum < 0)
|
|
ereport(ERROR,
|
|
(errcode(ERRCODE_TRIGGERED_ACTION_EXCEPTION),
|
|
errmsg("\"%s\" has no attribute \"%s\"",
|
|
relname, args[0])));
|
|
|
|
/*
|
|
* Check the target field has an allowed type, and get the current
|
|
* datetime as a value of that type.
|
|
*/
|
|
atttypid = SPI_gettypeid(tupdesc, attnum);
|
|
if (atttypid == TIMESTAMPOID)
|
|
newdt = DirectFunctionCall3(timestamp_in,
|
|
CStringGetDatum("now"),
|
|
ObjectIdGetDatum(InvalidOid),
|
|
Int32GetDatum(-1));
|
|
else if (atttypid == TIMESTAMPTZOID)
|
|
newdt = DirectFunctionCall3(timestamptz_in,
|
|
CStringGetDatum("now"),
|
|
ObjectIdGetDatum(InvalidOid),
|
|
Int32GetDatum(-1));
|
|
else
|
|
{
|
|
ereport(ERROR,
|
|
(errcode(ERRCODE_TRIGGERED_ACTION_EXCEPTION),
|
|
errmsg("attribute \"%s\" of \"%s\" must be type TIMESTAMP or TIMESTAMPTZ",
|
|
args[0], relname)));
|
|
newdt = (Datum) 0; /* keep compiler quiet */
|
|
}
|
|
|
|
/* 1 is the number of items in the arrays attnum and newdt.
|
|
attnum is the positional number of the field to be updated.
|
|
newdt is the new datetime stamp.
|
|
NOTE that attnum and newdt are not arrays, but then a 1 element array
|
|
is not an array any more then they are. Thus, they can be considered a
|
|
one element array.
|
|
*/
|
|
rettuple = SPI_modifytuple(rel, rettuple, 1, &attnum, &newdt, NULL);
|
|
|
|
if (rettuple == NULL)
|
|
/* internal error */
|
|
elog(ERROR, "moddatetime (%s): %d returned by SPI_modifytuple",
|
|
relname, SPI_result);
|
|
|
|
/* Clean up */
|
|
pfree(relname);
|
|
|
|
return PointerGetDatum(rettuple);
|
|
}
|