1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
<?php
/*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
* This software consists of voluntary contributions made by many individuals
* and is licensed under the MIT license. For more information, see
* <http://www.doctrine-project.org>.
*/
namespace Doctrine\DBAL\Id;
use Doctrine\DBAL\DriverManager;
use Doctrine\DBAL\Connection;
/**
* Table ID Generator for those poor languages that are missing sequences.
*
* WARNING: The Table Id Generator clones a second independent database
* connection to work correctly. This means using the generator requests that
* generate IDs will have two open database connections. This is necessary to
* be safe from transaction failures in the main connection. Make sure to only
* ever use one TableGenerator otherwise you end up with many connections.
*
* TableID Generator does not work with SQLite.
*
* The TableGenerator does not take care of creating the SQL Table itself. You
* should look at the `TableGeneratorSchemaVisitor` to do this for you.
* Otherwise the schema for a table looks like:
*
* CREATE sequences (
* sequence_name VARCHAR(255) NOT NULL,
* sequence_value INT NOT NULL DEFAULT '1',
* sequence_increment_by INT NOT NULL DEFAULT '1',
* PRIMARY KEY (table_name)
* );
*
* Technically this generator works as follows:
*
* 1. Use a robust transaction serialization level.
* 2. Open transaction
* 3. Acquire a read lock on the table row (SELECT .. FOR UPDATE)
* 4. Increment current value by one and write back to database
* 5. Commit transaction
*
* If you are using a sequence_increment_by value that is larger than one the
* ID Generator will keep incrementing values until it hits the incrementation
* gap before issuing another query.
*
* If no row is present for a given sequence a new one will be created with the
* default values 'value' = 1 and 'increment_by' = 1
*
* @author Benjamin Eberlei <kontakt@beberlei.de>
*/
class TableGenerator
{
/**
* @var \Doctrine\DBAL\Connection
*/
private $conn;
/**
* @var string
*/
private $generatorTableName;
/**
* @var array
*/
private $sequences = array();
/**
* @param \Doctrine\DBAL\Connection $conn
* @param string $generatorTableName
*
* @throws \Doctrine\DBAL\DBALException
*/
public function __construct(Connection $conn, $generatorTableName = 'sequences')
{
$params = $conn->getParams();
if ($params['driver'] == 'pdo_sqlite') {
throw new \Doctrine\DBAL\DBALException("Cannot use TableGenerator with SQLite.");
}
$this->conn = DriverManager::getConnection($params, $conn->getConfiguration(), $conn->getEventManager());
$this->generatorTableName = $generatorTableName;
}
/**
* Generates the next unused value for the given sequence name.
*
* @param string $sequenceName
*
* @return integer
*
* @throws \Doctrine\DBAL\DBALException
*/
public function nextValue($sequenceName)
{
if (isset($this->sequences[$sequenceName])) {
$value = $this->sequences[$sequenceName]['value'];
$this->sequences[$sequenceName]['value']++;
if ($this->sequences[$sequenceName]['value'] >= $this->sequences[$sequenceName]['max']) {
unset ($this->sequences[$sequenceName]);
}
return $value;
}
$this->conn->beginTransaction();
try {
$platform = $this->conn->getDatabasePlatform();
$sql = "SELECT sequence_value, sequence_increment_by " .
"FROM " . $platform->appendLockHint($this->generatorTableName, \Doctrine\DBAL\LockMode::PESSIMISTIC_WRITE) . " " .
"WHERE sequence_name = ? " . $platform->getWriteLockSQL();
$stmt = $this->conn->executeQuery($sql, array($sequenceName));
if ($row = $stmt->fetch(\PDO::FETCH_ASSOC)) {
$row = array_change_key_case($row, CASE_LOWER);
$value = $row['sequence_value'];
$value++;
if ($row['sequence_increment_by'] > 1) {
$this->sequences[$sequenceName] = array(
'value' => $value,
'max' => $row['sequence_value'] + $row['sequence_increment_by']
);
}
$sql = "UPDATE " . $this->generatorTableName . " ".
"SET sequence_value = sequence_value + sequence_increment_by " .
"WHERE sequence_name = ? AND sequence_value = ?";
$rows = $this->conn->executeUpdate($sql, array($sequenceName, $row['sequence_value']));
if ($rows != 1) {
throw new \Doctrine\DBAL\DBALException("Race-condition detected while updating sequence. Aborting generation");
}
} else {
$this->conn->insert(
$this->generatorTableName,
array('sequence_name' => $sequenceName, 'sequence_value' => 1, 'sequence_increment_by' => 1)
);
$value = 1;
}
$this->conn->commit();
} catch (\Exception $e) {
$this->conn->rollback();
throw new \Doctrine\DBAL\DBALException("Error occurred while generating ID with TableGenerator, aborted generation: " . $e->getMessage(), 0, $e);
}
return $value;
}
}