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How can I programmatically get
the next free device number (vdevno) in SQL 6.5 and below? CREATE PROCEDURE sp_ms_NextDeviceNumber AS /*RETURNS THE NEXT AVAILABLE SEQUENTIAL DEVICE NUMBER Created by Mike Schellenberger*/ /* Get a list of used device numbers > 0 and put in a temporary table */ SELECT dev_num = CONVERT(tinyint, SUBSTRING(CONVERT(binary(4), d.low),v.low, 1)) INTO #TmpDevHoldTable FROM master..sysdevices d, master.dbo.spt_values v WHERE v.type = 'E' AND v.number = 3 AND convert(tinyint, substring(convert(binary(4), d.low),v.low, 1)) > 0 ORDER BY dev_num /* Now lets find the first available device from the temporary table */ SET ROWCOUNT 1 /* This gets only the first one available */ SELECT Next_Available_Device_# = t1.dev_num + 1 FROM #TmpDevHoldTable t1 WHERE NOT EXISTS /* When current dev number + 1 does not exist */ (SELECT t2.dev_num /* we are here and have our 1 row */ FROM #TmpDevHoldTable t2 WHERE t1.dev_num + 1 = t2.dev_num) SET ROWCOUNT 0 DROP TABLE #TmpDevHoldTable GO |
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