IBM_DB2 platform doesn't handle offset without limit

[morozov]

There's a non-empty table users. The following script should return all existing record IDs.

$builder = $conn->createQueryBuilder();
$builder->select('id')
    ->from('users')
    ->setFirstResult(0);
$data = $builder->execute()->fetchAll();
var_dump($data);

It does so on Oracle, SQL Server and MySQL, but returns empty result on DB2. The reason is that resulting SQL has a condition like WHERE db22.DC_ROWNUM BETWEEN 1 AND 0.

[deeky666]

Patch is good, just some minor CS adjustments required.

[deeky666]

Can you use empty() here?

[morozov]

Sure. Just trying to understand the requirements, is empty($array) somehow better than count($array)? IMO, empty() is prone to typos like empty($were) which one may not notice w/o running tests.

[deeky666]

@morozov this is just about minor optimizations. empty() is a language construct and much more efficient than using the function count(). The point about typos is a good point, but in DBAL we try to code as much performance efficient as possible even if it seems neglible. Thanks for changing.

[morozov]

@deeky666 gotcha, thanks, will keep that in mind in the future.

[deeky666]

Can you return early here like return sprintf()?

[deeky666]

@morozov thanks for your effort!

[deeky666]

Backported to 2.5 via 0f7bf0c