Thank you James & Yeswa
  
 Collection way is a stable option. However it is not fit for us because of the efficiency issue. Our source data sometimes contain more than 30k transactions in one workbook, read and write will spend much time. And sometimes  will suffer system collapse when read into collection.
  
 Eric Li
 AIG
  
 Automation Delivery Team | China Service Center
  
 9F, The Centerpoint (Shuion), 374-2 Beijing Road, Guangzhou,  China 510030
  
 Tel: (+86 20) 2882 5022
  
 Eric-F.Li@aig.com  | www.aig.com
  
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