I too am bummed this feature didn't make it in, but it just didn't make
it to the station on time and the doors shut before it could jump on.
Sorry to say that it is a general policy (AFAIK) not to add new features
to maintenance branch such as 10.1. People in production with Derby
don't like potentially destabilizing features such as this added to a
maintenance release which is supposed to be just about bug-fixes.
Since this did not make the cut for 10.2, this feature won't see the
light of day until 10.3, which probably won't happen for another six
months. However, hopefully we'll be making snapshots/drops available of
the 10.3 release early and often. Even these snapshots (and even our
nightly builds) are generally quite well tested so depending on what
you're doing you can probably start working with it fairly soon. I
regularly work with the latest build off the codeline and am quite happy
with its stability (but then I'm not running it in production...)
David
David Heath (JIRA) wrote:
[ http://issues.apache.org/jira/browse/DERBY-119?page=comments#action_12432604 ]
David Heath commented on DERBY-119:
-----------------------------------
Do you have an idea when this feature will make it into a non-alpha release -
will it make it into 10.1 branch?
Derby is one of the DBMS we use in our application and currently we are working
on tools to help in the migration of our data model from one version to the
next. In doing so, I am hoping to have the ability to change the NULL
constraint on a column. I had assumed Derby already supported this behavior and
only discovered yesterday that its is a new feature and has only made it into
the 10.2 branch.
Add ALTER TABLE option to change column from NULL to NOT NULL
-------------------------------------------------------------
Key: DERBY-119
URL: http://issues.apache.org/jira/browse/DERBY-119
Project: Derby
Issue Type: New Feature
Components: SQL
Reporter: Bernd Ruehlicke
Assigned To: Bryan Pendleton
Fix For: 10.3.0.0
Attachments: alterColumnNotNull_1.diff, alterColumnNotNull_v2.diff,
alterColumnNotNull_v3.diff
There was a thread about this on the Cloudscape forum
http://www-106.ibm.com/developerworks/forums/dw_thread.jsp?message=4103269&cat=19&thread=59941&forum=370#4103269
Since this describes the problem I will just copy the content of this entry as
my dexscription
The content of this was
"
Hi,
I stumbled across a behaviour of cloudscape which is not a bug but IMHO an
implementation choice. To assign a primary key to a table using ALTER TABLE all
columns must be declared NOT NULL first, which can only be specified upon
column creation (no ALTER TABLE statement exists to change the NOT NULL
property of a column).
Most databases I know do two things differently:
1) when a primary key is assigned all pk columns are automatically set to NOT
NULL, if one of them contains NULL values, the ALTER TABLE statement fails
2) it is possible to alter the column to set the NOT NULL property after column
creation (fails when there are already records containing NULL values)
If I have understood the limitations correctly in Cloudscape I have no choice
but to remove and re-add the column which is supposed to be used in the primary
key, if it is not already declared as NOT NULL. This means that in the case of
a table containing valid data (unique and not null) in the column in all
records, I would have to export the data, remove and re-add the column and
reimport that data, which would not be necessary e.g. in Oracle or MaxDB.
Is it possible to change that behaviour or is there a good reason for it? It looks as if it makes the life of the user more difficult than necessary for certain metadata manipulations. Making it possible to alter the NOT NULL property of a column would solve this and IMHO having a primary key constraint do this implicitly makes sense as well.
Thanks in advance for any insight on this,
Robert"
