Hibernate: Automatic Versioning Nullable Column

Question

I have a table which contains huge data. I want to add hibernate automatic versioning to this table. But adding a not-null column to this table for versioning is very expensive due to huge data. Is there a workaround so hibernate can work with nullable column? Currently hibernate gives NPE because it tries to increment a null value. ( As hibernate manages this internally, changing the version value on client side is out of question ) Any other versioning startegy is welcome too. Thanks in advance

Answer 1

If your flavour of database permits it you could use the DEFAULT option. This is against Oracle ...

SQL> create table t23 as select object_id as id from user_objects;

Table created.

SQL> desc t23
 Name                                      Null?    Type
 ----------------------------------------- -------- ----------------------------
 ID                                                 NUMBER

SQL> alter table t23 add hibernate_version_number number default 0 not null;

Table altered.

SQL> desc t23
 Name                                      Null?    Type
 ----------------------------------------- -------- ----------------------------
 ID                                                 NUMBER
 HIBERNATE_VERSION_NUMBER                  NOT NULL NUMBER

SQL> select count(*) from t23 where hibernate_version_number = 0;

  COUNT(*)
----------
       504

SQL>

However, you may still want to benchmark its performance against a realistic volume of data. It may not solve your problem.