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Oracle platform ignores OFFSET in case if LIMIT is not specified #2509

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Merged
deeky666 merged 1 commit into from
Jan 16, 2017
Merged

Oracle platform ignores OFFSET in case if LIMIT is not specified #2509

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31 changes: 18 additions & 13 deletions lib/Doctrine/DBAL/Platforms/OraclePlatform.php
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Original file line number Diff line number Diff line change
Expand Up @@ -977,24 +977,29 @@ public function getName()
*/
protected function doModifyLimitQuery($query, $limit, $offset = null)
{
$limit = (int) $limit;
$offset = (int) $offset;
if ($limit === null && $offset === null) {
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@deeky666 deeky666 Jan 14, 2017

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Can you please remove the integer casting entirely and just rely on the method signature integer|null for both $limit and $offset? Then just check everywhere against null. Also please remove the $has* variables as they are unnecessary.

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@morozov morozov Jan 14, 2017 •
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@deeky666 The confusing part here is how is $offset = null different from $offset = 0 from the SQL semantics standpoint? Should the DBAL produce additional sub-query in the latter case? Right now it doesn't which makes more sense to me.

UPD: comparing $offset to null will break unit test:

1) Doctrine\Tests\DBAL\Platforms\OraclePlatformTest::testModifyLimitQuery
Failed asserting that two strings are equal.
--- Expected
+++ Actual
@@ @@
-'SELECT a.* FROM (SELECT * FROM user) a WHERE ROWNUM <= 10'
+'SELECT * FROM (SELECT a.*, ROWNUM AS doctrine_rownum FROM (SELECT * FROM user) a WHERE ROWNUM <= 10) WHERE doctrine_rownum >= 1'

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@deeky666 deeky666 Jan 14, 2017

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@morozov yeah good point. But then leave it as before casting both parameters to int and checking for 0 instead.

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@morozov morozov Jan 15, 2017

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@deeky666 but unlike OFFSET, for LIMIT 0 and null have different meanings — "0 records" and "all records" respectively. There's no complete consistency between existing adapters but all of them except SQL Anywhere only omit $limit when it's null. Technically, it is possible to execute a query and retrieve 0 records from it, so the DBAL shouldn't be a limiting factor here. Also from the API consumer standpoint, if there's a bug in the calculation of $limit on the application end and it's calculated as 0, I'd better expect 0 records to be returned instead of all of them.

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@deeky666 deeky666 Jan 16, 2017

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@morozov sounds reasonable. Thanks for clearing that up. I'll accept it as is now.

return $query;
}

if (preg_match('/^\s*SELECT/i', $query)) {
if (!preg_match('/\sFROM\s/i', $query)) {
$query .= " FROM dual";
}
if ($limit > 0) {
$max = $offset + $limit;
$column = '*';
if ($offset > 0) {
$min = $offset + 1;
$query = 'SELECT * FROM (SELECT a.' . $column . ', rownum AS doctrine_rownum FROM (' .
$query .
') a WHERE rownum <= ' . $max . ') WHERE doctrine_rownum >= ' . $min;
} else {
$query = 'SELECT a.' . $column . ' FROM (' . $query . ') a WHERE ROWNUM <= ' . $max;
}

$columns = array('a.*');

if ($offset > 0) {
$columns[] = 'ROWNUM AS doctrine_rownum';
}

$query = sprintf('SELECT %s FROM (%s) a', implode(', ', $columns), $query);

if ($limit !== null) {
$query .= sprintf(' WHERE ROWNUM <= %d', $offset + $limit);
}

if ($offset > 0) {
$query = sprintf('SELECT * FROM (%s) WHERE doctrine_rownum >= %d', $query, $offset + 1);
}
}

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1 change: 1 addition & 0 deletions tests/Doctrine/Tests/DBAL/Functional/ModifyLimitQueryTest.php
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Expand Up @@ -42,6 +42,7 @@ public function testModifyLimitQuerySimpleQuery()
$this->assertLimitResult(array(1, 2, 3, 4), $sql, 10, 0);
$this->assertLimitResult(array(1, 2), $sql, 2, 0);
$this->assertLimitResult(array(3, 4), $sql, 2, 2);
$this->assertLimitResult(array(2, 3, 4), $sql, null, 1);
}

public function testModifyLimitQueryJoinQuery()
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12 changes: 12 additions & 0 deletions tests/Doctrine/Tests/DBAL/Platforms/OraclePlatformTest.php
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Expand Up @@ -263,6 +263,18 @@ public function testModifyLimitQueryWithEmptyOffset()
$this->assertEquals('SELECT a.* FROM (SELECT * FROM user) a WHERE ROWNUM <= 10', $sql);
}

public function testModifyLimitQueryWithNonEmptyOffset()
{
$sql = $this->_platform->modifyLimitQuery('SELECT * FROM user', 10, 10);
$this->assertEquals('SELECT * FROM (SELECT a.*, ROWNUM AS doctrine_rownum FROM (SELECT * FROM user) a WHERE ROWNUM <= 20) WHERE doctrine_rownum >= 11', $sql);
}

public function testModifyLimitQueryWithEmptyLimit()
{
$sql = $this->_platform->modifyLimitQuery('SELECT * FROM user', null, 10);
$this->assertEquals('SELECT * FROM (SELECT a.*, ROWNUM AS doctrine_rownum FROM (SELECT * FROM user) a) WHERE doctrine_rownum >= 11', $sql);
}

public function testModifyLimitQueryWithAscOrderBy()
{
$sql = $this->_platform->modifyLimitQuery('SELECT * FROM user ORDER BY username ASC', 10);
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