CODEWITHSUNDEEP
javasqlspringhibernate
Paperback Writer
Paperback Writer

Reputation: 2125

Fail silently on constraint violation

I have entity Foo, which maps to sql table with some unique constraints. Thus saving Foo may fail. I am using FooDao to save Foo:

@Repository
public class FooDao
{
  @Autowired
  private SessionFactory sessionFactory;

  @Transactional
  @Override
   public void add(Foo item) {
    sessionFactory.save(item);
   }
}

when I call method FooDao#add(Foo) it may fail for two reasons: either because of unique constraint violation (in this case, I know how to handle the problem) or because of some other problem (in this I probably should propagate the exception). How do I distinguish between those two situations?

I could add method find(Foo item) to FooDao and check, whether something like item, which I was trying to add is database. But this would require additional select from database and I am a bit worried about this.

Upvotes: 0

Views: 542

Answers (4)

sbzoom
sbzoom

Reputation: 3373

If there is a database exception it gets caught in a HibernateException, which is a checked exception. Spring wraps this in a DataAccessException, which is unchecked. This exception will run up to your Controller and out to the Servlet and end up in a stack trace in the browser and log file. You can catch this exception and print it out so you can see what is happening. This will at least get you to the point where you know what is actually breaking.

Bad keys is probably one issue. But bad values is probably another. Some non-null fields are null, or something isn't long/short enough etc. Fixing this probably involves validation. You can use the Hibernate Validator. You give your fields some nifty annotations and then you get validation errors in java before you even get to the database - errors happen faster.

Upvotes: 0

Maddy
Maddy

Reputation: 923

Thats actually SQLState.

do something like this

Catch(HibernateException he){
   SQLException sqe = he.getSQLEception();
   String sqlState = sqe.getSQLState();
   if(sqlState.equals("23000"){
       // Handle your exception
   } 
}

Java doc: SQLState - an XOPEN or SQL:2003 code identifying the exception

One link I found for ISO sqlStates,

link to reference

But look for exact reference and value..

Upvotes: 1

Maddy
Maddy

Reputation: 923

Catch org.hibernate.JDBCException. This has getErrorCode(). For unique constraint voilation its ORA-00001.

-Maddy

Upvotes: 0

seba.wagner
seba.wagner

Reputation: 3860

One obvious (but maybe nasty) solution is that you catch javax.persistence.PersistenceException and parse the error message for "violant" or "constraint".

From my point of view you should do the select/find upfront. Remember that you are using an ORM! Hibernate has caches involved so neither the select/find nor the key contraint error might be the result of an actual db query but the result of an calculation of Hibernate based on your already in cache loaded data.

Sebastian

Upvotes: 0

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