Built in Constraint Validation before DML

Question

I have generated Business Components from DB Tables and FK's. When I run the AM in testmode, I expected the Entity Constraints to be checked either upon item validation time or at DML time. But the framework tries to commit invalid data (e.g. child rows w/o matching parent rows) to the DB and displays the resulting Oracle Error as SQLException. Was I expecting wrong, or have Entity Constraints never been thought to be validated at runtime ? If the latter is true, is there any way to generate declarative validation logic for the EO's that reflect the Entity Constraints besides of the not null Check Constraints? I find the need to declare validation logic which matches information accessible for JDev not a task compliant with "productivity with choice".
And, what is the Key Properties meaning in the Entity Constraint Editor - Properties dialogue ?
I find it an advantage to test the constraints before performing DML, as does good old Designer generated Forms (no rolled back TX, more accurate user information possible).

Answer 1

You can expose accessors for each end of an association. For example, say you have tables Emp and Dept. If you have an association between them (joining Emp.DeptId to Dept.Id for example) you can expose the accessors. Then, in the EmpImpl.java file you could use that accessor to get at the associated record in the Dept table. You could then check to see if there is an associated record by calling the getDept() method call in the EmpImpl.java file. I'm not sure how accurate this is, I'd have to look into it further, but it doesn't matter for me because I am commiting on every action so the cache should always be consistent with the DB (except during this transaction obviously)...
If you need more information on using this method I suggest opening a new thread specifically about it.
I used to be of the opinion that you should check everything at the application level to save trips to the Database and cut down on DB load. However, there are things that a database does much better than application code, such as catching constraint violations. As such, I do basic validations and then send it to the DB if it passes. The only problem I have with this is that by default JDevloper throws really ugly database error messages which the average user will not understand. To bypass this I found that you can override the default error messages and create a lookup for error messages where you can catch the DB errors and provide user-friendly versions. I have forgotten the steps involved, but it uses the DBTransactionFactory and other classes... I will look for the old thread I got it from later if you like...