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From Edson Carlos Ericksson Richter <edson.rich...@mgrinformatica.com.br>
Subject Re: DROP NOT NULL constraint
Date Thu, 23 Feb 2006 22:42:00 GMT
AFAIK, this, and several other metadata changes are not allowed. Check 
following issues (the most important IMHO missed in Derby) in Jira:

DERBY-342: At least basic (like operator) comparision between long 
varchar (and clob). IMHO, related to DERBY-472 (see bellow).

DERBY-396, DERBY-119: Alter table DROP/RENAME/MODIFY column, suporting 
rename of column even if part of referencial integrity; drop column with 
release of space; modify column from NULL to NOT NULL - if NOT NULL 
specified and table has records, then a DEFAULT is mandatory. Besides 
it's not too usefull in production database, it's a fundamental feature 
for development and upgrading times.

DERBY-239: Non-blocking online backup. A must have for production 
databases 24 x 7 x 365.

DERBY-84: allow using column aliases in ORDER BY and HAVING because the 
column alias could be a complex expression (in reality, I think its a 
new variant from DERBY-84). Unique database I know allow this is MSSQL 
since 2000 version (in ORDER BY - not in Having). Allow simplify queries.

DERBY-533, DERBY-554: Is a basic must-have for latin american 
developers/users for adoption.

DERBY-472: Full-text indexing could allow very fast search. IMHO, it's 
DERBY-342 related (if we could make full text searchs over long 
varchar/clob would be amazing!).


Piotr Bzdyl escreveu:

> Hello,
>
> I found out that it is impossible to drop a column in a table in 
> derby. I thought that I can live with that if I could drop not null 
> constraint from the column I need to drop and leave that column unused.
>
> But: how can I drop not null constraint on the column?
>
> Best regards,
> Piotr
>
>


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