<?php namespace Doctrine\DBAL\Sharding; /** * Sharding Manager gives access to APIs to implementing sharding on top of * Doctrine\DBAL\Connection instances. * * For simplicity and developer ease-of-use (and understanding) the sharding * API only covers single shard queries, no fan-out support. It is primarily * suited for multi-tenant applications. * * The assumption about sharding here * is that a distribution value can be found that gives access to all the * necessary data for all use-cases. Switching between shards should be done with * caution, especially if lazy loading is implemented. Any query is always * executed against the last shard that was selected. If a query is created for * a shard Y but then a shard X is selected when its actually executed you * will hit the wrong shard. */ interface ShardManager { /** * Selects global database with global data. * * This is the default database that is connected when no shard is * selected. * * @return void */ public function selectGlobal(); /** * Selects the shard against which the queries after this statement will be issued. * * @param string $distributionValue * * @return void * * @throws ShardingException If no value is passed as shard identifier. */ public function selectShard($distributionValue); /** * Gets the distribution value currently used for sharding. * * @return string|null */ public function getCurrentDistributionValue(); /** * Gets information about the amount of shards and other details. * * Format is implementation specific, each shard is one element and has an * 'id' attribute at least. * * @return mixed[][] */ public function getShards(); /** * Queries all shards in undefined order and return the results appended to * each other. Restore the previous distribution value after execution. * * Using {@link Connection::fetchAll()} to retrieve rows internally. * * @param string $sql * @param mixed[] $params * @param int[]|string[] $types * * @return mixed[] */ public function queryAll($sql, array $params, array $types); }