10-Lock.txt

declare 

  cursor C_PRODUCT is select  * from PRODUCT for update of SALESPRICE;
  R_PRODUCT PRODUCT%ROWTYPE;

begin
 
    lock table PRODUCT in share mode;

    open C_PRODUCT;
    
    loop
        fetch C_PRODUCT into R_PRODUCT;
        exit when C_PRODUCT%NOTFOUND;
		
        update PRODUCT
        set SALESPRICE=SALESPRICE+ SALESPRICE*0.1
        where current of C_PRODUCT ;
    end loop;

    close C_PRODUCT;

end;



lock table PRODUCT in exlusive mode;
lock table PRODUCT in share mode nowait;