2009/11/11 Bastien Koert <phpster@xxxxxxxxx>:
> On Tue, Nov 10, 2009 at 4:14 PM, Timothy Legg <php_list@xxxxxxxxxxxxxxx> wrote:
>>
>> Hello,
>>
>> Is it wrong to have mysql_connect() called twice within a single PHP
>> document, such as this? I have been running into some fairly annoying
>> query failures that commute when I change the order of these two blocks of
>> code. I am currently working around this by repeatedly using
>> mysql_select_db() to change the databases as I am needing to change to a
>> different database.
>>
>> To be more specific, I can use the $db_material handle in doing a query,
>> but it will always try to search in the Labor_Log table and thus fail
>> because the tables have different and names. Swapping these blocks will
>> have a vice-versa effect.
>>
>>
>> //Connect to server (materials)
>> $db_material = mysql_connect("localhost", "root", "secret");
>> if (!$db_material)
>> {
>> echo( "<P>Unable to connect to the database server at this
>> time.</P>" );
>> exit();
>> }
>> mysql_select_db("Material_Log", $db_material);
>>
>>
>> //Connect to server (labor)
>> $db_labor = mysql_connect("localhost", "root", "secret");
>> if (!$db_labor)
>> {
>> echo( "<P>Unable to connect to the database server at this
>> time.</P>" );
>> exit();
>> }
>> mysql_select_db("Labor_Log", $db_labor);
>>
>>
>>
>> Tim Legg
>>
>>
>> --
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>>
>>
>
> If the databases are in the same mysql server, then you could qualify
> the table select with the database name and simply re-use the
> connection
>
> select db_name.table_name.field from db_name.table_name [where]
>
>
> --
>
> Bastien
>
> Cat, the other other white meat
>
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>
>
As I understand things, if you make 2 or more connections to the same
database server with the same credentials, you end up with 1 shared
connection.
This is assuming you are not using mysql_pconnect() and you are not
using the new_link option on mysql_connect().
See http://svn.php.net/viewvc/php/php-src/trunk/ext/mysql/php_mysql.c?view=markup#l864.
If you then use change DB on one of the connection, you are changing
it for both.
The answer is to use a single connection and a fully qualified name to
the table.
SELECT Alias.Column FROM Database.Table.Column AS Alias
sort of thing.
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