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From "Andreas Korneliussen (JIRA)" <derby-...@db.apache.org>
Subject [jira] Commented: (DERBY-690) Add scrollable, updatable, insensitive result sets
Date Wed, 01 Mar 2006 14:09:17 GMT
    [ http://issues.apache.org/jira/browse/DERBY-690?page=comments#action_12368286 ] 

Andreas Korneliussen commented on DERBY-690:
--------------------------------------------

I found the following in the JDBC 2.1 spec:
"
5.8.3 A result set s own changes We have pointed out that the visibility of changes made by
others generally depends on a result set s type. A final point that concerns the visibility
of changes via an open result set is whether a result set can see its own changes (inserts,
updates, and deletes). A JDBC technology application can determine if the changes made by
a result set are vis-ible to the result set itself by calling the DatabaseMetaData methods:
ownUpdate-sAreVisible, ownDeletesAreVisible, and ownInsertsAreVisible. These methods are needed
since this capability can vary between DBMSs and JDBC drivers. One s own updates are visible
if an updated column value can be retrieved by calling getXXX() following a call to updateXXX().
"

So the visibility of the ResultSets own changes does not have anything to do with the value
in the database, it is the values you set when calling updateXXX().  (The values do not go
down to the database until updateRow() is called).  

Has this been changed in JDBC 3 and later ?

> Add scrollable, updatable, insensitive result sets
> --------------------------------------------------
>
>          Key: DERBY-690
>          URL: http://issues.apache.org/jira/browse/DERBY-690
>      Project: Derby
>         Type: New Feature
>   Components: JDBC
>     Reporter: Dag H. Wanvik
>     Assignee: Dag H. Wanvik
>     Priority: Minor
>  Attachments: DERBY-690-v1.diff, DERBY-690-v1.stat, DERBY-690-v2.diff, DERBY-690-v2.stat,
SURChanges-v1.pdf, sur-proposal.txt, writeup-v1.html, writeup-v2.html
>
> JDBC result sets are created with three properties: type, concurrency
> and holdability. The type can be one of TYPE_FORWARD_ONLY,
> TYPE_SCROLL_INSENSITIVE and TYPE_SCROLL_SENSITIVE. The concurrency can
> be one of CONCUR_READ_ONLY and CONCUR_UPDATABLE. The holdability can
> be one of HOLD_CURSORS_OVER_COMMIT and CLOSE_CURSORS_AT_COMMIT.
> JDBC allows the full cross product of these. SQL 2003 prohibits the
> combination {TYPE_SCROLL_INSENSITIVE, CONCUR_UPDATABLE}, but this
> combination is supported by some vendors, notably Oracle.
> Currently, Derby supports JDBC result sets in a limited
> way. Holdability is supported. Furthermore, the following is
> supported: 
> 	   - forward-only, read-only 
> 	   - forward-only, updatable (update, delete, but not insert)
> 	     Also, in the network driver, support for some data types
> 	     conversions is missing.
> 	   - scroll insensitive, read-only
> We (Fernanda and Andreas will cooperate with me on this) propose a
> plan to add support for the combination:
> 	   - scroll insensitive, updatable
> for both the embedded driver and the network client driver. 
> As a part of this we would also like to add the missing insert
> operation to the {forward-only, updatable} result sets (JIRA-100), and
> remove the requirement for an explicit "FOR UPDATE" clause in the SQL
> query to achieve updatability if CONCUR_UPDATABLE is specified
> (JIRA-231).
> The full proposal text is uploaded as an attachment, including a proposed
> functional specification.
> This JIRA will  be used to track sub-issues for this effort. The sub-issues will be linked
back to this issue.

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