Insert data from Front end to Back end

Question

Please help me this is urgent 

How we will update data of other table by using gridview data of another table 

Suppose we have 2 table tb1 and tb2 . tb1 is containing the columns AgentId and AgentName &  tb2 is containg columns as AgentId,AgentName and CmsnMoney.

First we are fetching the record of tb1 to Gridview.Data of tb1 is displaying in Gridview now we have to update the tb2 data by updating of gridview's tb1 data