[TYPO3-dev] Database compare and database modification inconsistencies

[Jigal van Hemert]

Hi,

On 3-1-2012 9:46, Xavier Perseguers wrote:
> Steffen Gebert wrote:
>>> The database compare and database modification have inconsistencies which
>>> are quite confusing. It's quite easy to write an ext_tables.sql which
>>> will
>>> be applied on database, but actually never show as "up do date" in
>>> extension manager (so it seems it didn't apply). This is mostly
>>> because of
>>> limitation around "NOT NULL" and "DEFAULT" values.
>>
>> Xavier, what's the opinion of the DBAL fraction?
>
> Just went through this post and the answer to "why SQL is rewritten" is
> to be understandable and compatible with DBAL.

To expand on this a bit more: TYPO3 uses/supports a subset of SQL/MySQL. 
This is done to be able to support other DBMS than MySQL. DBAL adds some 
user functions to other DBMS so they can use some MySQL specific 
functions or rewrites queries which use those functions or 
constructions. Support for DBMS other than MySQL is quite important for 
an Enterprise level CMS.
This imposes some limitations to the table structures you can use and 
the queries you can write, but these limitations do not make it 
impossible to implement the functionality you want.

Unfortunately many extension developers don't see the need to produce 
DBAL compatible tables/queries.

While the database compare routines could be improved I don't agree with 
the OP remark that SQL should be applied as it was written. It should be 
written according to the supported features.

-- 
Kind regards / met vriendelijke groet,

Jigal van Hemert.