我已经查看了SQL 主键约束，尽管记录不存在SO 上的所有问题中哪一个似乎最接近我的问题，但并不相同。
我毫不怀疑我可能在做一些愚蠢的事情，但这里是：
我正在尝试编写一个脚本（在 php 中），它将数据（没有结构，它假设结构已经完成）从任何给定的 PDO 数据库迁移到任何其他给定的 PDO 数据库 - 在我的情况下，我正在 sqlite3 上对其进行测试 - > mysql。
当我在我的测试数据库上运行脚本时，我得到“完整性约束违规：1062 Duplicate entry '1' for key 'PRIMARY'”我不太明白，因为表中没有数据（即使在脚本运行之前它也是删除语句）。
我假设它与主键是 auto_increment 的事实有关，但我尝试将下一个增量值设置为插入的任何值以外的值（认为我尝试将其设置为 80） - 没有区别。
我一直在寻找一种在交易期间禁用 auto_increment 的方法，但没有事先更改表，然后再将其更改回来，我想不出办法 - 更改整个表似乎是错误的，我真的不想涉及任何 DDL。
1 <?php
2
3 $abspath = dirname(__FILE__)."/";
4
5 $source_dsn = 'sqlite:'.$abspath.'db.sqlitedb';
6 $source_username = null;
7 $source_password = null;
8 $target_dsn = "mysql:dbname=name;host=127.0.0.1";
9 $target_username = "name";
10 $target_password = "pass";
11
12 $transfer_data = array();
13 $table_data = array();
14
15 try {
16
17 // connect to source
18 $source = new PDO($source_dsn, $source_username, $source_password);
19 $source->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
20
21 // connect to target
22 $target = new PDO($target_dsn, $target_username, $target_password);
23 $target->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
24
25 //TODO Generalise this statement to all database types.
26 $stmt = $source->prepare("SELECT * FROM sqlite_master WHERE type='table';");
27 $stmt->execute();
28
29 // get all tables
30 while($tablerow = $stmt->fetch(PDO::FETCH_ASSOC))
31 {
32 // TODO Generalise these statements to all database types.
33 $transfer_data[$tablerow['tbl_name']] = array();
34 $table_data[$tablerow['tbl_name']] = array();
35 }
36 $stmt->closeCursor();
37
38 // for each table, load data
39 foreach($transfer_data as $tablename => $void)
40 {
41 $stmt = $source->prepare("SELECT * FROM $tablename;");
42 $stmt->execute();
43 // load data row at a time
44 while($datarow = $stmt->fetch(PDO::FETCH_ASSOC))
45 {
46 // store data for later
47 $transfer_data[$tablename][] = $datarow;
48 // if we haven't gained column data yet, do so now
49 if(!array_key_exists($tablename,$table_data))
50 {
51 $t_data = array();
52 foreach($datarow as $colname => $void)
53 {
54 $t_data[] = $colname;
55 }
56 $table_data[$tablename] = $t_data;
57 }
58 }
59 $stmt->closeCursor();
60 echo "Read $tablename\n";
61 }
62
63 //start a transaction (if driver supports transactions / if not then this is noop)
64 $target->beginTransaction();
65 // for each table clear existing data and insert copied data
66 foreach($table_data as $tablename => $columns)
67 {
68 // not using an empty/truncate because mysql and possibly others autocommit
69 $stmt = $target->prepare("DELETE FROM $tablename;");
70 $stmt->execute();
71 $stmt->closeCursor();
72
73 // prepare the insert statement - we don't know how many columns so is dynamic
74 $querystr = "INSERT INTO $tablename (".join(", ",$columns).") VALUES (";
75 foreach($columns as $k => $column)
76 {
77 $columns[$k] = ':'.$column;
78 }
79 // using named placeholders so order doesn't matter
80 $querystr = $querystr.join(", ",$columns).");";
81 $stmt = $target->prepare($querystr);
82 //echo "Using: $querystr\n";
83 $rowcount = 0;
84 // for each row of data, bind data and execute insert statement
85 foreach($transfer_data[$tablename] as $rowdata)
86 {
87 foreach($rowdata as $rowname => $rowvalue)
88 {
89 $stmt->bindParam(':'.$rowname, $rowvalue);
90 }
91 $stmt->execute();
92 $stmt->closeCursor();
93 $rowcount++;
94 }
95 echo "Written $rowcount rows to $tablename\n";
96 }
97 $target->commit();
98
99 }
100 catch (PDOException $e)
101 {
102 echo 'PDO Error: '.get_class($e).' - '.$e->getMessage()."\n";
103 echo 'Query String was: '.$querystr."\nData:\n";
104 var_export($transfer_data[$tablename]);
105 if($target->inTransaction()){
106 $target->rollBack();
107 }
108 }
109
现在我的目标数据库中有一个表：
+-------------------+------------------+------+-----+---------+----------------+
| Field | Type | Null | Key | Default | Extra |
+-------------------+------------------+------+-----+---------+----------------+
| channel_id | int(11) | NO | PRI | NULL | auto_increment |
| channel_parent_id | int(10) unsigned | YES | | NULL | |
| server_id | int(10) unsigned | NO | MUL | NULL | |
+-------------------+------------------+------+-----+---------+----------------+
输出是：
PDO Error: PDOException - SQLSTATE[23000]: Integrity constraint violation: 1062 Duplicate entry '1' for key 'PRIMARY'
Query String was: INSERT INTO channels (channel_id, channel_parent_id, server_id) VALUES (:channel_id, :channel_parent_id, :server_id);
Data:
array (
0 =>
array (
'channel_id' => '1',
'channel_parent_id' => '0',
'server_id' => '1',
),
1 =>
array (
'channel_id' => '24',
'channel_parent_id' => '0',
'server_id' => '1',
),
2 =>
array (
'channel_id' => '34',
'channel_parent_id' => '0',
'server_id' => '1',
),