Hello.

I'd like to ask is it possible to make Hibernate work without referential integrity?

For the case we face there's a running DBMS and it's the one without referential integrity defined. We have no right to change it.

For some version of DBMS such as MySQL there's no referential integrity. We want the mapping do be done without that.

How can we deal with those case?

Well, where is the Problem? If there are no foreign key constraints, hibernate won't violate any. I don't undestand your problem.

Yes

The problem is sometimes hibernate will generate the Integrity Constraints SQL Statements in the DDL. Then there will be some problem for those databases which don't support such constraints. e.g. some older version of MySQL.

Is there anyway of making the Integrity Constraints DLL generation an option step?

e.g. imagine the schemaexport can accept a parameter that omit the integrity constraints DDL generation, then it will generate only the create table statements. And the actual integrity is managed by the Hibernate API as specified in the mapping xml file.

Is it possible doing something like that? Or any other alternatives?

Thx.

Hum, I don't know about the SchemaExport, but for sure Hibernate core don't need referencial integrity

Some background information: one objective of the software project that I am working on is to support as many kinds of DBMS as possible. Our team has insight on Hibernate having such edge. So we try to adpot it.

The success of this decision relys on how Hibernate generate DDL for a specific kinds of database in different versions.

Can we consider all the DB type and its version by changing the SQLDialect class supplied in the configuration?

Thx.

You have to suppose:
- good support of SQL by your underlying DB (those having a dialect are, see http://www.hibernate.org/Documentation/CompatibilityGuide)
- not too bad JDBC driver

Dialect is done to customize Hibernate relation to DB, so I guess the answer to your question is yes.

From Hibernate Compatbility Guide: It is highly likely that most features of Hibernate (ie. everything except schema generation) will work perfectly with many other relational databases.

So does it mean given we can define the DDL in advance (without Referential Integrity DDL) and then have a corresponding Mapping file (with Referential Integrity) then the intrgration will still be successful?

But using this method, we can not let the hibernate to select a good mapping for some "risky" types such as date, which different DBMS's implementation on that is quite difficult.

Is there any suggestion on this situation.

p.s.
- date is entensively used throughout the project. So it's highly desirable to delegate the responibility of selecting the suitable date type for different database, where the type of database in some sense unknown in advance. (assuming that we are going to support all database that is supported by Hibernate, given an not-too-bad JDBC driver)

- How do we know if a JDBC driver is not-too-bad? How do we measure or judge its capabilities?

Thx.