illuminate/database 使用 一

illuminate/database 是完整的php数据库工具包，即ORM（Object-Relational Mapping）类库。

提供丰富的查询构造器，和多个驱动的服务。作为Laravel的数据库层使用，也可以单独使用。

一 使用

加载composer之后，创建Illuminate\Database\Capsule\Manager对象，配置连接数据后可将其全局化，之后调用全局化的变量使用构造方法等进行查询。

二 代码

require_once './vendor/autoload.php';

use Illuminate\Container\Container;
use Illuminate\Database\Capsule\Manager as DB;
use Illuminate\Events\Dispatcher;

class BasedDB
{
    private $config;
    public function __construct($config)
    {
        $this->config = [
            'driver' => 'mysql',
            'host' => $config["host"],
            'database' => $config["database"],
            'username' => $config["username"],
            'password' => $config["password"],
            'charset' => $config["charset"],
            'collation' => $config["collation"],
            'prefix' => $config["prefix"],
        ];
        $this->init();
    }
    public function init()
    {
        $db = new DB();
        $db->addConnection($this->config);
        $db->setEventDispatcher(new Dispatcher(new Container));
        $db->setAsGlobal(); //设置静态全局可用
        $db->bootEloquent();
    }

}

class TestDB extends BasedDB
{
    public function test1()
    {
        //构造查询
        $info = DB::table('userinfo')->where('id', '=', 2)->get();
        var_dump($info);
    }
}
$config = [
    'driver' => 'mysql',
    'host' => 'localhost',
    'database' => 'test',
    'username' => 'root',
    'password' => 'qwe110110',
    'charset' => 'utf8',
    'collation' => 'utf8_general_ci',
    'prefix' => '',
];
$t = new TestDB($config);
$t->test1();

三 原理

从代码可见从Illuminate\Database\Capsule\Manager::addConnection($config)开始。

addConnection仅设置配置。该类的构造参数中包含Illuminate\Container\Container类，通过Manager::setupContainer()函数传入Container类对象，获取绑定的配置。

Container类中Container::bound()判断是否有绑定的内容。使用Container::bind()绑定内容，会删除共享实例中对应的别名内容。绑定时若为指定绑定类的具体类或者说闭包，会自动处理，若未执行则实际处理类为指定的类，利用反射返回对应实例，否则直接返回已有实例。

Manager::setEventDispatcher() 从字面意思是设置事件调度程序。传入参数Illuminate\Events\Dispatcher类实例。通过查看代码，Dispatcher可以用Dispatcher::listen()、Dispatcher::push()、Dispatcher::dispatch()、Dispatcher::until()可以设置监听或调度监听。

Manager::setAsGlobal()将Manager全局化，可以用调用静态对象方法调用。

Manager::bootEloquent()启动Eloquent，其中调用Manager::getEventDispatcher()获取默认的程序调度，Eloquent::setEventDispatcher设置Eloquent的事件调度。Manager::getEventDispatcher()获取绑定的events内容。

到此为止初始化结束，没有出现获取pdo的内容。

调用Manager::table()开始查询，通过调用Manager自己的静态类调用connection，即static::$instance->connection()。

之后调用DatabaseManager::connection()方法。

DatabaseManager通过解析传入的配置名获取配置。若配置名为空则默认为default，可以调用DatabaseManager::setDefaultConnection()设置默认配置名。根据配置名获取配置，通过\Illuminate\Database\Connectors\ConnectionFactory工厂类匹配对应驱动，返回对应pdo对象。

比如返回Illuminate\Database\MySqlConnector对象。该类处理对应驱动特殊处理方法，比如数据库连接、设置事务隔离级别等。

table方法最后调用的是Illuminate\Database\Connection::table(),其为MySqlConnector父类。DatabaseManager::__call($method, $parameters)处理传如的数据并执行，该方法实际返回ConnectionFactory类创建的Illuminate\Database\Query\Builder对象，模式构建器调用结束的时候，将构造器对象作为参数，整合成查询字符串执行查询。

四 源码

1、初始化

根据代码可以绑定config类，或者自定义配置；可以设置events。

//Illuminate\Database\Capsule\Manager

use Illuminate\Container\Container;

class Manager
{
    use CapsuleManagerTrait;
    protected $manager;

    /**
     * Create a new database capsule manager.
     *
     * @param  \Illuminate\Container\Container|null  $container
     * @return void
     */
    public function __construct(Container $container = null)
    {
        $this->setupContainer($container ?: new Container);

        // Once we have the container setup, we will setup the default configuration
        // options in the container "config" binding. This will make the database
        // manager work correctly out of the box without extreme configuration.
        $this->setupDefaultConfiguration();

        $this->setupManager();
    }
     /**
     * Register a connection with the manager.
     *
     * @param  array  $config
     * @param  string  $name
     * @return void
     */
    public function addConnection(array $config, $name = 'default')
    {
        $connections = $this->container['config']['database.connections'];

        $connections[$name] = $config;

        $this->container['config']['database.connections'] = $connections;
    }
    /**
     * Get the current event dispatcher instance.
     *
     * @return \Illuminate\Contracts\Events\Dispatcher|null
     */
    public function getEventDispatcher()
    {
        if ($this->container->bound('events')) {
            return $this->container['events'];
        }
    }
    /**
     * Setup the default database configuration options.
     *
     * @return void
     */
    protected function setupDefaultConfiguration()
    {
        $this->container['config']['database.fetch'] = PDO::FETCH_OBJ;

        $this->container['config']['database.default'] = 'default';
    }
    /**
     * Set the event dispatcher instance to be used by connections.
     *
     * @param  \Illuminate\Contracts\Events\Dispatcher  $dispatcher
     * @return void
     */
    public function setEventDispatcher(Dispatcher $dispatcher)
    {
        $this->container->instance('events', $dispatcher);
    }
    /**
     * Bootstrap Eloquent so it is ready for usage.
     *
     * @return void
     */
    public function bootEloquent()
    {
        Eloquent::setConnectionResolver($this->manager);

        // If we have an event dispatcher instance, we will go ahead and register it
        // with the Eloquent ORM, allowing for model callbacks while creating and
        // updating "model" instances; however, it is not necessary to operate.
        if ($dispatcher = $this->getEventDispatcher()) {
            Eloquent::setEventDispatcher($dispatcher);
        }
    }
}


//Illuminate\Support\Traits\CapsuleManagerTrait
trait CapsuleManagerTrait
{
    /**
     * Make this capsule instance available globally.
     *
     * @return void
     */
    public function setAsGlobal()
    {
        static::$instance = $this;
    }
     /**
     * Setup the IoC container instance.
     *
     * @param  \Illuminate\Contracts\Container\Container  $container
     * @return void
     */
    protected function setupContainer(Container $container)
    {
        $this->container = $container;

        if (! $this->container->bound('config')) {
            $this->container->instance('config', new Fluent);
        }
    }
}

//\Illuminate\Contracts\Container\Container
use Illuminate\Contracts\Container\Container as ContainerContract;
class Container implements ArrayAccess, ContainerContract
{
     /**
     * Determine if the given abstract type has been bound.
     *
     * @param  string  $abstract
     * @return bool
     */
    public function bound($abstract)
    {
        return isset($this->bindings[$abstract]) ||
               isset($this->instances[$abstract]) ||
               $this->isAlias($abstract);
    }
    /**
     * Register a binding with the container.
     *
     * @param  string  $abstract
     * @param  \Closure|string|null  $concrete
     * @param  bool  $shared
     * @return void
     *
     * @throws \TypeError
     */
    public function bind($abstract, $concrete = null, $shared = false)
    {
        $this->dropStaleInstances($abstract);

        // If no concrete type was given, we will simply set the concrete type to the
        // abstract type. After that, the concrete type to be registered as shared
        // without being forced to state their classes in both of the parameters.
        if (is_null($concrete)) {
            $concrete = $abstract;
        }

        // If the factory is not a Closure, it means it is just a class name which is
        // bound into this container to the abstract type and we will just wrap it
        // up inside its own Closure to give us more convenience when extending.
        if (! $concrete instanceof Closure) {
            if (! is_string($concrete)) {
                throw new TypeError(self::class.'::bind(): Argument #2 ($concrete) must be of type Closure|string|null');
            }

            $concrete = $this->getClosure($abstract, $concrete);
        }

        $this->bindings[$abstract] = compact('concrete', 'shared');

        // If the abstract type was already resolved in this container we'll fire the
        // rebound listener so that any objects which have already gotten resolved
        // can have their copy of the object updated via the listener callbacks.
        if ($this->resolved($abstract)) {
            $this->rebound($abstract);
        }
    }
    /**
     * Register an existing instance as shared in the container.
     *
     * @param  string  $abstract
     * @param  mixed  $instance
     * @return mixed
     */
    public function instance($abstract, $instance)
    {
        $this->removeAbstractAlias($abstract);

        $isBound = $this->bound($abstract);

        unset($this->aliases[$abstract]);

        // We'll check to determine if this type has been bound before, and if it has
        // we will fire the rebound callbacks registered with the container and it
        // can be updated with consuming classes that have gotten resolved here.
        $this->instances[$abstract] = $instance;

        if ($isBound) {
            $this->rebound($abstract);
        }

        return $instance;
    }
    /**
     * Remove an alias from the contextual binding alias cache.
     *
     * @param  string  $searched
     * @return void
     */
    protected function removeAbstractAlias($searched)
    {
        if (! isset($this->aliases[$searched])) {
            return;
        }

        foreach ($this->abstractAliases as $abstract => $aliases) {
            foreach ($aliases as $index => $alias) {
                if ($alias == $searched) {
                    unset($this->abstractAliases[$abstract][$index]);
                }
            }
        }
    }
}

2、构造器

//Illuminate\Database\Capsule\Manager
use Illuminate\Database\DatabaseManager;
class Manager
{
    protected $manager;

    /**
     * Create a new database capsule manager.
     *
     * @param  \Illuminate\Container\Container|null  $container
     * @return void
     */
    public function __construct(Container $container = null)
    {
        $this->setupContainer($container ?: new Container);

        // Once we have the container setup, we will setup the default configuration
        // options in the container "config" binding. This will make the database
        // manager work correctly out of the box without extreme configuration.
        $this->setupDefaultConfiguration();

        $this->setupManager();
    }
     /**
     * Build the database manager instance.
     *
     * @return void
     */
    protected function setupManager()
    {
        $factory = new ConnectionFactory($this->container);

        $this->manager = new DatabaseManager($this->container, $factory);
    }
    /**
     * Dynamically pass methods to the default connection.
     *
     * @param  string  $method
     * @param  array  $parameters
     * @return mixed
     */
    public static function __callStatic($method, $parameters)
    {
        return static::connection()->$method(...$parameters);
    }
    /**
     * Get a connection instance from the global manager.
     *
     * @param  string|null  $connection
     * @return \Illuminate\Database\Connection
     */
    public static function connection($connection = null)
    {
        return static::$instance->getConnection($connection);
    }
    /**
     * Get a registered connection instance.
     *
     * @param  string|null  $name
     * @return \Illuminate\Database\Connection
     */
    public function getConnection($name = null)
    {
        return $this->manager->connection($name);
    }
    /**
     * Get a fluent query builder instance.
     *
     * @param  \Closure|\Illuminate\Database\Query\Builder|string  $table
     * @param  string|null  $as
     * @param  string|null  $connection
     * @return \Illuminate\Database\Query\Builder
     */
    public static function table($table, $as = null, $connection = null)
    {
        return static::$instance->connection($connection)->table($table, $as);
    }
}

//Illuminate\Database\DatabaseManager
use Illuminate\Database\Connectors\ConnectionFactory;
/**
 * @mixin \Illuminate\Database\Connection
 */
class DatabaseManager implements ConnectionResolverInterface
{
    public function __construct($app, ConnectionFactory $factory)
    {
        $this->app = $app;
        $this->factory = $factory;

        $this->reconnector = function ($connection) {
            $this->reconnect($connection->getNameWithReadWriteType());
        };
    }
    /**
     * Get a database connection instance.
     *
     * @param  string|null  $name
     * @return \Illuminate\Database\Connection
     */
    public function connection($name = null)
    {
        [$database, $type] = $this->parseConnectionName($name);

        $name = $name ?: $database;

        // If we haven't created this connection, we'll create it based on the config
        // provided in the application. Once we've created the connections we will
        // set the "fetch mode" for PDO which determines the query return types.
        if (! isset($this->connections[$name])) {
            $this->connections[$name] = $this->configure(
                $this->makeConnection($database), $type
            );
        }

        return $this->connections[$name];
    }
    /**
     * Make the database connection instance.
     *
     * @param  string  $name
     * @return \Illuminate\Database\Connection
     */
    protected function makeConnection($name)
    {
        $config = $this->configuration($name);

        // First we will check by the connection name to see if an extension has been
        // registered specifically for that connection. If it has we will call the
        // Closure and pass it the config allowing it to resolve the connection.
        if (isset($this->extensions[$name])) {
            return call_user_func($this->extensions[$name], $config, $name);
        }

        // Next we will check to see if an extension has been registered for a driver
        // and will call the Closure if so, which allows us to have a more generic
        // resolver for the drivers themselves which applies to all connections.
        if (isset($this->extensions[$driver = $config['driver']])) {
            return call_user_func($this->extensions[$driver], $config, $name);
        }

        return $this->factory->make($config, $name);
    }
}

//Illuminate\Database\Connectors\ConnectionFactory
class ConnectionFactory
{
    /**
     * Establish a PDO connection based on the configuration.
     *
     * @param  array  $config
     * @param  string|null  $name
     * @return \Illuminate\Database\Connection
     */
    public function make(array $config, $name = null)
    {
        $config = $this->parseConfig($config, $name);

        if (isset($config['read'])) {
            return $this->createReadWriteConnection($config);
        }

        return $this->createSingleConnection($config());
    }
    /**
     * Parse and prepare the database configuration.
     *
     * @param  array  $config
     * @param  string  $name
     * @return array
     */
    protected function parseConfig(array $config, $name)
    {
        return Arr::add(Arr::add($config, 'prefix', ''), 'name', $name);
    }
    /**
     * Create a read / write database connection instance.
     *
     * @param  array  $config
     * @return \Illuminate\Database\Connection
     */
    protected function createReadWriteConnection(array $config)
    {
        $connection = $this->createSingleConnection($this->getWriteConfig($config));

        return $connection->setReadPdo($this->createReadPdo($config));
    }
    /**
     * Create a read / write database connection instance.
     *
     * @param  array  $config
     * @return \Illuminate\Database\Connection
     */
    protected function createReadWriteConnection(array $config)
    {
        $connection = $this->createSingleConnection($this->getWriteConfig($config));

        return $connection->setReadPdo($this->createReadPdo($config));
    }
    /**
     * Create a single database connection instance.
     *
     * @param  array  $config
     * @return \Illuminate\Database\Connection
     */
    protected function createSingleConnection(array $config)
    {
        $pdo = $this->createPdoResolver($config);

        return $this->createConnection(
            $config['driver'], $pdo, $config['database'], $config['prefix'], $config
        );
    }
    /**
     * Get the write configuration for a read / write connection.
     *
     * @param  array  $config
     * @return array
     */
    protected function getWriteConfig(array $config)
    {
        return $this->mergeReadWriteConfig(
            $config, $this->getReadWriteConfig($config, 'write')
        );
    }
    /**
     * Merge a configuration for a read / write connection.
     *
     * @param  array  $config
     * @param  array  $merge
     * @return array
     */
    protected function mergeReadWriteConfig(array $config, array $merge)
    {
        return Arr::except(array_merge($config, $merge), ['read', 'write']);
    }
    /**
     * Get a read / write level configuration.
     *
     * @param  array  $config
     * @param  string  $type
     * @return array
     */
    protected function getReadWriteConfig(array $config, $type)
    {
        return isset($config[$type][0])
        ? Arr::random($config[$type])
        : $config[$type];
    }
    /**
     * Create a single database connection instance.
     *
     * @param  array  $config
     * @return \Illuminate\Database\Connection
     */
    protected function createSingleConnection(array $config)
    {
        $pdo = $this->createPdoResolver($config);

        return $this->createConnection(
            $config['driver'], $pdo, $config['database'], $config['prefix'], $config
        );
    }
    /**
     * Create a connector instance based on the configuration.
     *
     * @param  array  $config
     * @return \Illuminate\Database\Connectors\ConnectorInterface
     *
     * @throws \InvalidArgumentException
     */
    public function createConnector(array $config)
    {
        if (!isset($config['driver'])) {
            throw new InvalidArgumentException('A driver must be specified.');
        }

        if ($this->container->bound($key = "db.connector.{$config['driver']}")) {
            return $this->container->make($key);
        }

        switch ($config['driver']) {
            case 'mysql':
                return new MySqlConnector;
            case 'pgsql':
                return new PostgresConnector;
            case 'sqlite':
                return new SQLiteConnector;
            case 'sqlsrv':
                return new SqlServerConnector;
        }

        throw new InvalidArgumentException("Unsupported driver [{$config['driver']}].");
    }
    /**
     * Create a new connection instance.
     *
     * @param  string  $driver
     * @param  \PDO|\Closure  $connection
     * @param  string  $database
     * @param  string  $prefix
     * @param  array  $config
     * @return \Illuminate\Database\Connection
     *
     * @throws \InvalidArgumentException
     */
    protected function createConnection($driver, $connection, $database, $prefix = '', array $config = [])
    {
        if ($resolver = Connection::getResolver($driver)) {
            return $resolver($connection, $database, $prefix, $config);
        }

        switch ($driver) {
            case 'mysql':
                return new MySqlConnection($connection, $database, $prefix, $config);
            case 'pgsql':
                return new PostgresConnection($connection, $database, $prefix, $config);
            case 'sqlite':
                return new SQLiteConnection($connection, $database, $prefix, $config);
            case 'sqlsrv':
                return new SqlServerConnection($connection, $database, $prefix, $config);
        }

        throw new InvalidArgumentException("Unsupported driver [{$driver}].");
    }
}

//Illuminate\Database\MySqlConnection
class MySqlConnection extends Connection
{
}

//Illuminate\Database\Connection
use Illuminate\Database\Query\Builder as QueryBuilder;
class Connection implements ConnectionInterface
{
     /**
     * Begin a fluent query against a database table.
     *
     * @param  \Closure|\Illuminate\Database\Query\Builder|string  $table
     * @param  string|null  $as
     * @return \Illuminate\Database\Query\Builder
     */
    public function table($table, $as = null)
    {
        return $this->query()->from($table, $as);
    }
    /**
     * Get a new query builder instance.
     *
     * @return \Illuminate\Database\Query\Builder
     */
    public function query()
    {
        return new QueryBuilder(
            $this, $this->getQueryGrammar(), $this->getPostProcessor()
        );
    }
}

//Illuminate\Database\Query\Builder
class Builder
{
    /**
     * Set the table which the query is targeting.
     *
     * @param  \Closure|\Illuminate\Database\Query\Builder|string  $table
     * @param  string|null  $as
     * @return $this
     */
    public function from($table, $as = null)
    {
        if ($this->isQueryable($table)) {
            return $this->fromSub($table, $as);
        }

        $this->from = $as ? "{$table} as {$as}" : $table;

        return $this;
    }
    /**
     * Determine if the value is a query builder instance or a Closure.
     *
     * @param  mixed  $value
     * @return bool
     */
    protected function isQueryable($value)
    {
        return $value instanceof self ||
               $value instanceof EloquentBuilder ||
               $value instanceof Relation ||
               $value instanceof Closure;
    }
    /**
     * Makes "from" fetch from a subquery.
     *
     * @param  \Closure|\Illuminate\Database\Query\Builder|string  $query
     * @param  string  $as
     * @return $this
     *
     * @throws \InvalidArgumentException
     */
    public function fromSub($query, $as)
    {
        [$query, $bindings] = $this->createSub($query);

        return $this->fromRaw('('.$query.') as '.$this->grammar->wrapTable($as), $bindings);
    }
    ……
    //之后都是构建构造器的 没调试 看的也不是太懂
}

注：

本地使用php版本7.4，illuminate/database为v8.83.27

illuminate/database composer地址:illuminate/database - Packagist

illuminate/database girbub地址:GitHub - illuminate/database: [READ ONLY] Subtree split of the Illuminate Database component (see laravel/framework)