The paper discusses the shortcomings of traditional ranking patternfor periodical shelves,thatis,ranking by periodical cataloguing,and putsforward the way of circulating shelve numbers,whichis able to be set in different ways in different libraries.

To establish drum level control simulation model of large-volume Heat Recovery Steam Generators(HRSG) and improve drum level control precision,it needs to gain accuracy level signals.

This article has discussed to establish automatic serial number and maintain safety and examine of system,which makes database system have the function of serving initiatively.