java - Delete from JDBC Derby Database using the auto-generated key (INTEGER NOT NULL GENERATED ALWAYS AS IDENTITY (START WITH 1, INCREMENT BY 1)) -

just wondering doing wrong here , how work around it. i've got simple table created so:

string createtablesql = (         "create table item_object_table ("         + "id integer not null generated identity (start 1, increment 1),"         + "item_object blob)");          preparedstatement ps = connection.preparestatement(createtablesql);          ps.execute(); 

the table stores blob of "item" object

anyway. delete method so:

public void deleteitem(int i) {     debug.write("attempting delete item id: "+i);     try       {         preparedstatement deletestatement = databaseconnector.preparestatement("delete item_object_table id=?");         deletestatement.setint(1, i);         deletestatement.execute();       } catch (sqlexception ex)       {         logger.getlogger(databasecontrol.class.getname()).log(level.severe, null, ex);       }  } 

this delete item not update integer id not null generated etc.

for example if database looked this:

 id 1 | blob data id 2 | blob data 

and called deleteitem(int id) method , parsed in int 1 (i.e. delete id 1) database this:

 id 2 | blob data 

the question is, how 'update' keys?

i'm little confused want here.

are saying when delete 1, expect id 2 updated use id 1 since id 1 gone?

if so, that's not how works, , fantastically inefficient , complex. have 200 tables referring id = 2 need cascading updates rename 1, , confusing db consumers well.

you may able control whether or not lowest available id reused instead of continuing highest id up, that's db specific question.