Hi again, a few hours ago I have read a question about ORM mapping for java . He wonders why  and when this technology is chosen.

Disclaimer: I am omitting the case, when your database is just a storage for a CRUD apps. I am talking about complex applications, when stored procedures are used very extensively, like Oracle’s PL/SQL.

Here comes the arguments :

I have some questions, like:
- What is your point to use ORM instead of plain SQL?
- What value ORM brings to you and how easy is to maintain the code, continue project?
- How easy new comers are getting along with your project?
- How quick and easy you update your system?
- What the performance is speed and resource usage wise?
- How generated SQL is efficient for your database and what is DB load does it provide?
- What is your way to cope with the situation, when you have a custom stored procedures package in your DB?

And the most important:
- If you ask yourself really honestly, so are you REALLY REALLY happy with ORM, rather than go with plain JDBC/SQL? I am talking in general principle, not just from some particular product perspective, that requires ORM to be used.

Here I see an out of date perspective:  “We have everything in database and database is faster and easier to develop then java”

• ALL of the ORM tools  have code generation utility  both binary and source code that saves lots of time and effort.
• They force you to put some abstraction layer between your Database and business layer. Abstraction is always GOOD unless it is extreme
• Interoperability: you can change your database vendor more easily even you can use different for your development and production enviroment!
• Enable more methodology: yes you can use interceptor soft-caches, clusters, aspects, listeners,notifiers and so on …
• Maintainable: which one is more maintainable code: your database, plsql, resultset or your domain objects and business layer !!!!
• Industry standards and trends: you can find more innovative tools and support when you are  following trends {jsf,seam}
• Learning curve: new graduates know more about POJOs objects then SQL/PLSQL and vendors
• Enables SQL if it is needed
• for more features:hibernate features and  toplink features

of course do not forget:

• ORM is efficient  only when dealing object one by one not fits for bulk operation and summary reports
• first learn: you should learn your tool to avoid pitfall
• you can always chose a framework like IBatis for such implementation

you can find discussion:

linkedin discussion

have a nice day

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