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@ -1,5 +1,5 @@ |
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<!-- |
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$PostgreSQL: pgsql/doc/src/sgml/trigger.sgml,v 1.39 2004/12/30 03:13:56 tgl Exp $ |
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$PostgreSQL: pgsql/doc/src/sgml/trigger.sgml,v 1.40 2005/01/22 22:06:27 momjian Exp $ |
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--> |
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<chapter id="triggers"> |
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@ -271,10 +271,10 @@ CALLED_AS_TRIGGER(fcinfo) |
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</programlisting> |
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which expands to |
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<programlisting> |
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((fcinfo)->context != NULL && IsA((fcinfo)->context, TriggerData)) |
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((fcinfo)->context != NULL && IsA((fcinfo)->context, TriggerData)) |
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</programlisting> |
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If this returns true, then it is safe to cast |
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<literal>fcinfo->context</> to type <literal>TriggerData |
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<literal>fcinfo->context</> to type <literal>TriggerData |
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*</literal> and make use of the pointed-to |
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<structname>TriggerData</> structure. The function must |
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<emphasis>not</emphasis> alter the <structname>TriggerData</> |
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@ -393,8 +393,8 @@ typedef struct TriggerData |
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A pointer to a structure describing the relation that the trigger fired for. |
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Look at <filename>utils/rel.h</> for details about |
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this structure. The most interesting things are |
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<literal>tg_relation->rd_att</> (descriptor of the relation |
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tuples) and <literal>tg_relation->rd_rel->relname</> |
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<literal>tg_relation->rd_att</> (descriptor of the relation |
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tuples) and <literal>tg_relation->rd_rel->relname</> |
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(relation name; the type is not <type>char*</> but |
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<type>NameData</>; use |
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<literal>SPI_getrelname(tg_relation)</> to get a <type>char*</> if you |
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@ -541,7 +541,7 @@ PG_FUNCTION_INFO_V1(trigf); |
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Datum |
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trigf(PG_FUNCTION_ARGS) |
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{ |
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TriggerData *trigdata = (TriggerData *) fcinfo->context; |
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TriggerData *trigdata = (TriggerData *) fcinfo->context; |
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TupleDesc tupdesc; |
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HeapTuple rettuple; |
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char *when; |
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@ -554,22 +554,22 @@ trigf(PG_FUNCTION_ARGS) |
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elog(ERROR, "trigf: not called by trigger manager"); |
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/* tuple to return to executor */ |
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if (TRIGGER_FIRED_BY_UPDATE(trigdata->tg_event)) |
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rettuple = trigdata->tg_newtuple; |
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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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rettuple = trigdata->tg_trigtuple; |
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rettuple = trigdata->tg_trigtuple; |
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/* check for null values */ |
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if (!TRIGGER_FIRED_BY_DELETE(trigdata->tg_event) |
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&& TRIGGER_FIRED_BEFORE(trigdata->tg_event)) |
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if (!TRIGGER_FIRED_BY_DELETE(trigdata->tg_event) |
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&& TRIGGER_FIRED_BEFORE(trigdata->tg_event)) |
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checknull = true; |
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if (TRIGGER_FIRED_BEFORE(trigdata->tg_event)) |
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if (TRIGGER_FIRED_BEFORE(trigdata->tg_event)) |
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when = "before"; |
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else |
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when = "after "; |
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tupdesc = trigdata->tg_relation->rd_att; |
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tupdesc = trigdata->tg_relation->rd_att; |
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/* connect to SPI manager */ |
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if ((ret = SPI_connect()) < 0) |
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@ -582,8 +582,8 @@ trigf(PG_FUNCTION_ARGS) |
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elog(NOTICE, "trigf (fired %s): SPI_exec returned %d", when, ret); |
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/* count(*) returns int8, so be careful to convert */ |
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i = DatumGetInt64(SPI_getbinval(SPI_tuptable->vals[0], |
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SPI_tuptable->tupdesc, |
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i = DatumGetInt64(SPI_getbinval(SPI_tuptable->vals[0], |
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SPI_tuptable->tupdesc, |
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1, |
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&isnull)); |
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Bruce Momjian
21 years ago