oracle - In which cases does a sql update statement return as no rows updated? -

in application using following code

if (m_ps.executeupdate() != 1) {              {                     throw new concurrentdbmodificationexception();                 }             } } 

the table updating present sure.

also table has timestamp colomn gets filled correctly.

it happens on customers environment cannot debug.

any appreciated.

thanks reading

the following case sql update statement return no rows updated :

update employees set salary = 14 age > 40

...basically when there no rows returned clause.

edit

considering "throw concurrentdbmodificationexception()", in case edited row has been deleted table while user using application edit information...