[TYPO3-v4] TYPO3 DBAL

[Jigal van Hemert]

Thomas "Thasmo" Deinhamer wrote:
> recently I often run into some mails, discussions etc. which mention
> DBAL in one or another way - so I was wondering...
> 
> TYPO3 doesn't use DBAL as default, does it?

No, but the Install Tool of TYPO3 4.4 includes support for DBAL to 
enable installation on a different DBMS than MySQL. In earlier versions 
installation on other DBMSs had to be done manually.

> I mean, I'm a bit confused what DBAL does in relation to TYPO3.

DBAL is a core extension which can replace the default database class by 
a class which supports databases other than MySQL. It does a bit more 
however: you can define which database connection must be used per table 
(this can also be useful if you want to use certain tables from another 
MySQL database), it rewrites queries to make them compatable with the 
DBMS which has to execute them, it can map table names to different 
table names (used for Oracle, which only allows table names with a 
maximum length of 30 characters), and probably a few more things.

> Is it "just" an extension which can be used instead of
> the TYPO3_DB object? In other words, can it replace TYPO3_DB?

DBAL extends typo3_db and this way it operates completely transparent to 
the rest of the system. So, you can use Typoscript objects like CONTENT 
to retrieve data from other databases, etc.

> Will it be implemented into the core in future or os it
> already implemented into the core?

It will probably never be included in the core because all these extra 
operations come at a price. Any overhead (even checks) will slow down 
the system.
Recently a lot of effort has been invested to move "optional" 
functionality from the core to system extensions (for example 
versioning/workspaces) to get a leaner and faster system for those who 
don't need these extra features.

-- 
Jigal van Hemert
skype:jigal.van.hemert
msn: jigal at xs4all.nl
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