using-batch-query-class

using-batch-query-class.php

/**
     * Starts a batch query.
     *
     * A batch query supports fetching data in batches, which can keep the memory usage under a limit.
     * This method will return a [[BatchQueryResult]] object which implements the [[\Iterator]] interface
     * and can be traversed to retrieve the data in batches.
     *
     * For example,
     *
     * ```php
     * foreach (User::model()->batch() as $rows) {
     *     // $rows is an array of 100 or fewer rows from user table
     * }
     * ```
     *
     * @param \CDbCriteria|array $criteria
     * @param int $batchSize the number of records to be fetched in each batch.
     * @return BatchQueryResult the batch query result. It implements the [[\Iterator]] interface
     * and can be traversed to retrieve the data in batches.
     */
    public function batch($criteria = [], $batchSize = 100)
    {
        return new BatchQueryResult($this->getDbConnection(), $batchSize, $this, $criteria, false);
    }

    /**
     * Starts a batch query and retrieves data row by row.
     * This method is similar to [[batch()]] except that in each iteration of the result,
     * only one row of data is returned. For example,
     *
     * ```php
     * foreach (User::model()->each() as $row) {
     *     // $row is an instance of ActiveRecord
     * }
     * ```
     *
     * @param \CDbCriteria|array $criteria
     * @param int $batchSize the number of records to be fetched in each batch.
     * @return BatchQueryResult the batch query result. It implements the [[\Iterator]] interface
     * and can be traversed to retrieve the data in batches.
     */
    public function each($criteria = [], $batchSize = 100)
    {
        return new BatchQueryResult($this->getDbConnection(), $batchSize, $this, $criteria, true);
    }