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适用于 >=php7.1 的 PDO 有用包装器

Database\DB 类实现了单例/多例设计模式。

表示例

CREATE TABLE IF NOT EXISTS `users` (
  `id` int(10) unsigned NOT NULL auto_increment,
  `role` varchar(50) NOT NULL,
  `name` varchar(50) NOT NULL,
  `email` varchar(50) NOT NULL,
  `visits` int(10) unsigned NOT NULL DEFAULT 0,
  `created` TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
  PRIMARY KEY (`id`)
);

INSERT INTO `users` (`id`, `role`, `name`, `email`) VALUES
(1, 'admin', 'John Smith', 'js@gmail.com'),
(2, 'user', 'Barbara Johnson', 'bj@gmail.com'),
(3, 'manager', 'Mary Lee', 'mee@gmail.com'),
(4, 'user', 'Lucia Woods', 'uw@gmail.com'),
(5, 'user', 'Brandon Alister', 'ba@gmail.com');

获取实例

use Database\DB;
use Database\DBExpression;

$db = DB::getInstanse(); // default db
$db2 = DB::getInstanse(DB::CONFIG_OTHER); // another db 

选择

// simple select
$rows = $db->selectAll('users', ['role' => 'admin']);

// select with NULL option
$rows = $db->selectAll('users', [
    'role' => 'admin', 
    'created' => 'IS NOT NULL' // or 'created' => 'IS NULL'
]);

选择行

$row = $db->selectRow('users', ['email' => 'admin@gmail.com']);

通过 id 选择行

$row = $db->selectRowById('users', 3);

选择列

$emails = $db->selectColumn('users', 'email');

选择单元格

$email = $db->selectCell('users', 'email', ['id' => 3]);

选择计数

$count = $db->selectCount('users');

插入数据

// simple insert
$id = $db->insert('users', ['role' => 'user', 'name' => 'new name', 'email' => 'new@gmail.com']);

// insert with mysql expression
$id = $db->insert('users', [
    'role' => 'user', 
    'name' => 'new name', 
    'email' => 'new@gmail.com', 
    'created' => new DBExpression('NULL') // or 'created' => null
]);

更新数据

// simple update
$affected = $db->update('users', ['role' => 'manager'], ['id' => 2]);

// update with mysql expression
$affected = $db->update('users', [
    'role' => 'manager', 
    'created' => new DBExpression('NOW()')
], ['id' => 2]);

更新计数器字段

$affected = $db->updateCounters('users', ['visits' => 1], ['id' => 3]);

检查现有记录

$isExist = $db->exists('users', ['role' => 'admin']);

删除行

$db->delete('users', ['visits' => 0]);

关闭所有实例的连接

DB::closeConections();