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			97 lines
		
	
	
		
			2.6 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
			
		
		
	
	
			97 lines
		
	
	
		
			2.6 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
| /*
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|  * insert_username.c
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|  * $Modified: Thu Oct 16 08:13:42 1997 by brook $
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|  * contrib/spi/insert_username.c
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|  *
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|  * insert user name in response to a trigger
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|  * usage:  insert_username (column_name)
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|  */
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| #include "postgres.h"
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| 
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| #include "catalog/pg_type.h"
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| #include "commands/trigger.h"
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| #include "executor/spi.h"
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| #include "miscadmin.h"
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| #include "utils/builtins.h"
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| #include "utils/rel.h"
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| 
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| PG_MODULE_MAGIC;
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| 
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| extern Datum insert_username(PG_FUNCTION_ARGS);
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| 
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| PG_FUNCTION_INFO_V1(insert_username);
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| 
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| Datum
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| insert_username(PG_FUNCTION_ARGS)
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| {
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| 	TriggerData *trigdata = (TriggerData *) fcinfo->context;
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| 	Trigger    *trigger;		/* to get trigger name */
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| 	int			nargs;			/* # of arguments */
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| 	Datum		newval;			/* new value of column */
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| 	char	  **args;			/* arguments */
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| 	char	   *relname;		/* triggered relation name */
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| 	Relation	rel;			/* triggered relation */
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| 	HeapTuple	rettuple = NULL;
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| 	TupleDesc	tupdesc;		/* tuple description */
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| 	int			attnum;
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| 
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| 	/* sanity checks from autoinc.c */
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| 	if (!CALLED_AS_TRIGGER(fcinfo))
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| 		/* internal error */
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| 		elog(ERROR, "insert_username: not fired by trigger manager");
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| 	if (!TRIGGER_FIRED_FOR_ROW(trigdata->tg_event))
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| 		/* internal error */
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| 		elog(ERROR, "insert_username: must be fired for row");
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| 	if (!TRIGGER_FIRED_BEFORE(trigdata->tg_event))
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| 		/* internal error */
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| 		elog(ERROR, "insert_username: must be fired before event");
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| 
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| 	if (TRIGGER_FIRED_BY_INSERT(trigdata->tg_event))
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| 		rettuple = trigdata->tg_trigtuple;
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| 	else if (TRIGGER_FIRED_BY_UPDATE(trigdata->tg_event))
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| 		rettuple = trigdata->tg_newtuple;
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| 	else
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| 		/* internal error */
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| 		elog(ERROR, "insert_username: cannot process DELETE events");
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| 
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| 	rel = trigdata->tg_relation;
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| 	relname = SPI_getrelname(rel);
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| 
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| 	trigger = trigdata->tg_trigger;
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| 
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| 	nargs = trigger->tgnargs;
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| 	if (nargs != 1)
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| 		/* internal error */
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| 		elog(ERROR, "insert_username (%s): one argument was expected", relname);
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| 
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| 	args = trigger->tgargs;
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| 	tupdesc = rel->rd_att;
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| 
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| 	attnum = SPI_fnumber(tupdesc, args[0]);
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| 
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| 	if (attnum < 0)
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| 		ereport(ERROR,
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| 				(errcode(ERRCODE_TRIGGERED_ACTION_EXCEPTION),
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| 				 errmsg("\"%s\" has no attribute \"%s\"", relname, args[0])));
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| 
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| 	if (SPI_gettypeid(tupdesc, attnum) != TEXTOID)
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| 		ereport(ERROR,
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| 				(errcode(ERRCODE_TRIGGERED_ACTION_EXCEPTION),
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| 				 errmsg("attribute \"%s\" of \"%s\" must be type TEXT",
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| 						args[0], relname)));
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| 
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| 	/* create fields containing name */
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| 	newval = CStringGetTextDatum(GetUserNameFromId(GetUserId()));
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| 
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| 	/* construct new tuple */
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| 	rettuple = SPI_modifytuple(rel, rettuple, 1, &attnum, &newval, NULL);
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| 	if (rettuple == NULL)
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| 		/* internal error */
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| 		elog(ERROR, "insert_username (\"%s\"): %d returned by SPI_modifytuple",
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| 			 relname, SPI_result);
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| 
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| 	pfree(relname);
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| 
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| 	return PointerGetDatum(rettuple);
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| }
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