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To: Ulf Wendel <ulf.wendel@oracle.com>
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Subject: Re: [PHP-DEV] mysqli tests breaking
From: php@hristov.com (Andrey Hristov)

  Hi,
On 09/05/2011 04:53 PM, Ulf Wendel wrote:
> This is the one and only mysqlnd-libmysql difference of some practical
> relevance. I consider it at least questionable if libmysql is correct.
>
> If it was to be decided that mysqlnd is wrong, it is probably like five
> lines of code in mysqlnd to change, if need be.
>
>
> Am 02.09.2011 19:19, schrieb Stas Malyshev:
>> API vs. SQL LAST_INSERT_ID()
>> [ext/mysqli/tests/mysqli_last_insert_id.phpt]
>> The reason is that this test relies on LAST_INSERT_ID() being reset on
>> SELECT. I have not observed such behavior neither via PHP not talking to
>> Mysql server directly from CLI interface, so I have no idea why this
>> test assumes such behavior.
>
> Personal observation and memory may not be the best reference here. What
> the test does is:
>
> DROP TABLE IF EXISTS test
> CREATE TABLE test(id INT AUTO_INCREMENT PRIMARY KEY) Engine=MyISAM
>
> INSERT INTO test(id) VALUES (1);
> printf("insert id for INSERT is: %d\n", mysqli_insert_id(link));
>
> SELECT 1 FROM DUAL
> printf("insert id for SELECT is: %d\n", mysqli_insert_id(link));
>
>
> Libmysql will print:
>
> insert id for INSERT is: 1
> insert id for SELECT is: 1

and here we see a bug. The value in libmysql is not reset, as the 
Documentation states. Clear bug.

> Mysqlnd will print:
>
> insert id for INSERT is: 1
> insert id for SELECT is: 0
>

mysqlnd does what is expected, as in many other cases :)

During mysqlnd's development we found numerous bugs in libmysql and 
reported them.

mysqlnd provided support for multiple result sets from prepared 
statements more than year earlier than libmysql even had code to handle 
this, which is in MySQL 5.5 now.

>
> "mysql_insert_id() returns 0 if the previous statement does not use an
> AUTO_INCREMENT value. If you need to save the value for later, be sure
> to call mysql_insert_id() immediately after the statement that generates
> the value."
>

Very clearly said.

LAST_INSERT_ID() is another story, but it has nothing to do with the 
client library.


Andrey