[TYPO3-dev] How standard compliant is "truncate"?

[ries van Twisk]

On Feb 5, 2009, at 6:35 AM, Steffen Kamper wrote:

> Hi,
>
> Martin Kutschker schrieb:
>>
>> Is truncate really faster?  I assumed that a DELETE without a WHERE
>> clause will work internally the same as a TRUNCATE.
>>
>
> for sure. We had some clients where clear cache lead to server crash.
> Truncate does the job in less a minute there. (MySQL)
>
> vg Steffen

truncate and delete without a where clause are not the same.

Truncate will usually not fire an ON DELETE triggers and foreign
references to wards the truncated table are not checked. if there are  
foreign references
the truncate will not continue and you have to truncate them all at  
the same time.
Implementations depend on the vendor but since TYPO3 is so simple in  
it's DB design the result of the command  would
almost be the same on all RDBM's

There is no TRUNCATE command in the SQL standard but it's implemented at
some DB vendors. Oracle, MySQL, PostgreSQL, mssql seems to support  
it....

A API in the db class would be on it's place.

..->getTruncateSQLCommand(Array $tables);

Would return the appropriate commands for the tables on the currently  
running DB.

Ries