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			78 lines
		
	
	
		
			2.3 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
			
		
		
	
	
			78 lines
		
	
	
		
			2.3 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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 *
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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 "executor/spi.h"		/* this is what you need to work with SPI */
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#include "commands/trigger.h"	/* -"- and triggers */
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#include "miscadmin.h"			/* for GetPgUserName() */
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HeapTuple	insert_username(void);
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HeapTuple
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insert_username()
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{
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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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	/* sanity checks from autoinc.c */
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	if (!CurrentTriggerData)
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		elog(ERROR, "insert_username: triggers are not initialized");
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	if (TRIGGER_FIRED_FOR_STATEMENT(CurrentTriggerData->tg_event))
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		elog(ERROR, "insert_username: can't process STATEMENT events");
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	if (TRIGGER_FIRED_AFTER(CurrentTriggerData->tg_event))
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		elog(ERROR, "insert_username: must be fired before event");
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	if (TRIGGER_FIRED_BY_INSERT(CurrentTriggerData->tg_event))
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		rettuple = CurrentTriggerData->tg_trigtuple;
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	else if (TRIGGER_FIRED_BY_UPDATE(CurrentTriggerData->tg_event))
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		rettuple = CurrentTriggerData->tg_newtuple;
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	else
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		elog(ERROR, "insert_username: can't process DELETE events");
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	rel = CurrentTriggerData->tg_relation;
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	relname = SPI_getrelname(rel);
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	trigger = CurrentTriggerData->tg_trigger;
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	nargs = trigger->tgnargs;
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	if (nargs != 1)
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		elog(ERROR, "insert_username (%s): one argument was expected", relname);
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	args = trigger->tgargs;
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	tupdesc = rel->rd_att;
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	CurrentTriggerData = NULL;
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	attnum = SPI_fnumber(tupdesc, args[0]);
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	if (attnum < 0)
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		elog(ERROR, "insert_username (%s): there is no attribute %s", relname, args[0]);
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	if (SPI_gettypeid(tupdesc, attnum) != TEXTOID)
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		elog(ERROR, "insert_username (%s): attribute %s must be of TEXT type",
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			 relname, args[0]);
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	/* create fields containing name */
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	newval = PointerGetDatum(textin(GetPgUserName()));
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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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		elog(ERROR, "insert_username (%s): %d returned by SPI_modifytuple",
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			 relname, SPI_result);
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	pfree(relname);
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	return (rettuple);
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}
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