UPDATING THE RELATIONAL DATABASE CONTAINING INDEFINITE AND MAYBE INFORMATIONS UNDER NULL VALUE CIRCUMSTANCES

Null value is introduced to the extended relational model of paper 1. To update the relational database under such circumstance, the extended relational model in paper 1 is further extended. On the basis of the extended model, the policy of updating relational database containing indefinite and maybe informations under null value circumstances is discussed, and the relevant algorithm of processing is given.