Re: [jira] [Commented] (EMPIREDB-200) Option to have non-persistent column in DBTable / DBView

[Siddhartha Upadhyaya <si...@yahoo.com>]

Hi Rainer,

I am new to this Empire DB and try to learn the capability it has. First of all I will like to thanks to you for your reply which show me the way to achieve my requirement.

I have one more question and just want to check with you before I go for any formal request. Please find those below:
1. Do we have any business logic validation mechanism for all the setter operation we perform against the Record ?

2. Do we have any callback mechanism for the life cycle of an Object, for example, when a record get created [not saved in database], when we modify a record or when we try to save a record.

3. This one is related to the Options we have. As per the example I notice the option is static values. If I want to provide the options against a list of dynamic values, How I can achieve it ?





On Sunday, 24 November 2013 11:02 PM, Rainer Döbele (JIRA) <em...@incubator.apache.org> wrote:
 

    [ https://issues.apache.org/jira/browse/EMPIREDB-200?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13830991#comment-13830991 ] 

Rainer Döbele commented on EMPIREDB-200:
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Yes, this one is a bit more tricky.
The question is, why do you need a database column at all, you can simply add a new property to your DBrecord derived class (you need the logic anyway), and use the getters and Setters.
But I agree sometimes you need metadata for that as well (like e.g. with our front-end-Extension like for JSF).
In this case you can define a DBColumnExpr in your table class together with the other table columns.
However still this would not be a true artifical column as it e.g. won't appear in the list of table columns.
In many years I have always been able to avoid this feature - but I must confess, that many times I had wished is exists before I found out again that I can live without.
But for simplicity it's worth considering it again - and weigh the pros and cons.
Anyone else who has an opinion on this?




> Option to have non-persistent column in DBTable / DBView
> --------------------------------------------------------
>
>                 Key: EMPIREDB-200
>                 URL: https://issues.apache.org/jira/browse/EMPIREDB-200
>             Project: Empire-DB
>          Issue Type: New Feature
>          Components: Core
>    Affects Versions: empire-db-2.4.2
>            Reporter: Siddhartha Upadhyaya
>
> Option to have non-persistent column in DBTable / DBView.
> We should have option to add a column / attribute for DBTable / DBView, which is non-persistent in nature. So, the value of the Column / attribute will not be stored in the Database, but it will be available as part of the Java Object to the application. The value of the column / attribute will be depend on the business logic.
> If we consider DBRecord is the Java Bean in an business layer. we may need to store some of the calculated data. This option will have us to do it.



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