Zend框架中的数据库事务：它们是孤立的吗？ [英] Database transactions in Zend Framework: Are they isolated?

问题描述

使用Zend Framework，我需要（1）从MySQL数据库读取记录，并且（2）立即写回到该记录以指示它已被读取。我不希望其他进程或查询能够在步骤（1）和（2）之间读取或写入相同的记录。

Using Zend Framework, I need to (1) read a record from a MySQL database, and (2) immediately write back to that record to indicate that it has been read. I don't want other processes or queries to be able to read from or write to the same record in between steps (1) and (2).

使用事务处理这些步骤。如果我使用以下方法，将满足我的要求？

I was considering using a transaction for these steps. If I use the following methods, will that fulfil my requirements?

Zend_Db_Adapter_Abstract::beginTransaction()
Zend_Db_Adapter_Abstract::commit()
Zend_Db_Adapter_Abstract::rollBack()

推荐答案

p>预设您正在使用 InnoDB引擎查看您是否将在以下地址发出交易：

Presupposing you are using the InnoDB engine for tables that you will issue transactions on:

如果要求您首先需要读取行并且独占锁定，在您更新它之前，您应该发出< a href =http://dev.mysql.com/doc/refman/5.5/en/innodb-locking-reads.html =noreferrer> SELECT ... FOR UPDATE 查询。像：

If the requirement is that you first need to read the row and exclusively lock it, before you are going to update it, you should issue a SELECT ... FOR UPDATE query. Something like:

$db->beginTransaction();
try
{
    $select = $db->select()
                 ->forUpdate() // <-- here's the magic
                 ->from(
                     array( 'a' => 'yourTable' ),
                     array( 'your', 'column', 'names' )
                 )
                 ->where( 'someColumn = ?', $whatever );

    $result = $this->_adapter->fetchRow( $select );

    /*
      alter data in $result
      and update if necessary:
    */
    $db->update( 'yourTable', $result, array( 'someColumn = ?' => $whatever ) );

    $db->commit();
}
catch( Exception $e )
{
    $db->rollBack();
}

或只需发出'raw' SELECT ...当然还有 $ UP 和 UPDATE SQL语句。

Or simply issue 'raw' SELECT ... FOR UPDATE and UPDATE SQL statements on $db of course.

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