Ashley Sheridan schreef: > On Wed, 2008-10-29 at 20:28 -0500, Micah Gersten wrote: >> Ashley Sheridan wrote: >>> On Wed, 2008-10-29 at 20:12 -0500, Micah Gersten wrote: >>> >>>> Waynn Lue wrote: >>>> >>>>>> With MySQL, you can change the DB from query to query with >>>>>> mysql_select_db. The alternative as I stated in my last post is to use >>>>>> the fully qualified table name (database.table) in your query. MySQL >>>>>> doesn't care which DB you have open if you do that. In both of these >>>>>> cases, the same connection is used. >>>>>> >>>>>> >>>>>> >>>>> That brings me back to the original point, is there a performance decrease >>>>> to continually calling mysql_select_db? And shouldn't connections that are >>>>> being made during the processing of a php script (which runs for no more >>>>> than two seconds) be lasting at least until the end of the script, instead >>>>> of getting errors like "Lost connection to server"? >>>>> >>>>> >>>>> >>>> The only overhead of constantly using mysql_select_db is 2 function >>>> calls to make a query instead of just using the database name in the >>>> query. However, this should not be that expensive. >>>> Yes, connections should be available for the whole script if you don't >>>> destroy them. >>>> >>>> Thank you, >>>> Micah Gersten >>>> >>>> >>> I'm just thinking about how other languages work with regards to >>> databases. I'm pretty sure that opening extra database connections, >>> regardless of whether they are on the same server or not, you will incur >>> extra opcodes. ColdFusion does it with MSSQL, and I'm guessing that PHP >>> on Windows using MSSQL or MySQL is going to be fairly the same. Linux >>> could be different, but why would the developers of the connection >>> driver write totally different code for both OS's? >>> >>> >>> Ash >>> www.ashleysheridan.co.uk >>> >> With MySQL, you don't need a new DB connection to use a second DB. I >> think that's the problem your having >> >> Thank you, >> Micah Gersten >> onShore Networks >> Internal Developer >> http://www.onshore.com >> >> >> >> > That's what I'm trying to explain. You don't have to explicitly code for > a new connection, but in terms of op codes, a new connection is created. no idea why your going on about op codes, and no a new connection is not made - there is merely switching between DBs on a single connection. it's the same as connecting with the mysql cmdline util and being able to browse any db by simply performing 'USE <DB>' queries ... those queries don't cause the mysql client to open new connections. > > > Ash > www.ashleysheridan.co.uk > > -- PHP General Mailing List (http://www.php.net/) To unsubscribe, visit: http://www.php.net/unsub.php
