Function dbms_sql_column_value

gpcontrib/orafce/dbms_sql.c:1703–1766

* CREATE PROCEDURE dbms_sql.column_value(c int, pos int, INOUT value "any"); * Note - CALL statement is slow from PLpgSQL block (against function execution). * This is reason why this routine is in function form too. */

 * This is reason why this routine is in function form too.
 */
Datum
dbms_sql_column_value(PG_FUNCTION_ARGS)
{
	CursorData *c;
	Datum		value;
	Datum		result;
	int			pos;
	bool		isnull;
	Oid			targetTypeId;
	Oid			resultTypeId;
	TupleDesc	resulttupdesc;
	HeapTuple	resulttuple;
	MemoryContext	oldcxt;

	if (SPI_connect() != SPI_OK_CONNECT)
		elog(ERROR, "SPI_connact failed");

	c = get_cursor(fcinfo, true);

	if (PG_ARGISNULL(1))
		ereport(ERROR,
			    (errcode(ERRCODE_NULL_VALUE_NOT_ALLOWED),
			     errmsg("column position (number) is NULL")));

	pos = PG_GETARG_INT32(1);

	if (!c->executed)
		ereport(ERROR,
			    (errcode(ERRCODE_INVALID_CURSOR_STATE),
			     errmsg("cursor is not executed")));

	oldcxt = MemoryContextSwitchTo(c->result_cxt);


	/*
	 * Setting of OUT field is little bit more complex, because although
	 * there is only one output field, the result should be compisite type.
	 */
	if (get_call_result_type(fcinfo, &resultTypeId, &resulttupdesc) == TYPEFUNC_COMPOSITE)
	{
		/* check target types */
		if (resulttupdesc->natts != 1)
			/* internal error, should not to be */
			elog(ERROR, "unexpected number of result composite fields");

		targetTypeId = get_fn_expr_argtype(fcinfo->flinfo, 2);
		Assert((TupleDescAttr(resulttupdesc, 0))->atttypid == targetTypeId);
	}
	else
		/* internal error, should not to be */
		elog(ERROR, "unexpected function result type");

	value = column_value(c, pos, targetTypeId, &isnull, false);

	resulttuple = heap_form_tuple(resulttupdesc, &value, &isnull);
	result = PointerGetDatum(SPI_returntuple(resulttuple, CreateTupleDescCopy(resulttupdesc)));

	SPI_finish();