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From:Steve Edberg Date:January 15 2000 1:23am
Subject:Re: mysql, php and server...
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At 04:08 PM 1/14/2000 , pons@stripped wrote:
>Hi.
>My name is Giulio.
>I'm an italian student and i'm doin' a work to get my
>degree at university.
>I have to create a database on a webserver.
>I have php and mysql on the server (the administrator
>told me) so i've decided to use this technology to do the
>work.
>In my project i have to explain how php and mysql
>works on server but i'm not sure i've understood everything
>of what i read on the internet.
>so here i am.
>
>I know that this is the sequence of the actions:
>
>0) web-user requires a php page
>1) the webserver passes the request to the php
>2) php calls mysql to use database
>3) mysql executes the query
>4) mysql sends results to php
>5) php generate an html page
>6) php passes html page to the webserver
>7) the webserver send html to the user
>
>I've read on manual that "MySQL is a database server" that
>is to say that it is the entity which uses the database
>files directly. isn't it?

Yes...the database server is an entity which understands a query language - 
usually some dialect of SQL - and searches the data tables for your 
request, and returns the appropriate records. HOW the DB server stores the 
records, WHERE it stores them, and how it indexes and searches them are its 
business. If you aren't a DBA (database administrator) you can generally 
consider the DB server to be a black box that accepts queries and returns 
sets of records. A program like Microsoft Access combines a database 
front-end (query generator, screen form design, etc) and report writer with 
a back-end database engine (I think Microsoft calls it the "Jet engine", 
but its performance is more in the propeller-driven class).

>Someone told me that ODBC is ALWAYS used when there is a
>database... but i'm not sure about it, i think that MySQL
>don't need ODBC to work.
>I'd like to know if ODBC is used in step 3.

No. ODBC (Open DataBase Connectivity, I think) is a 'standard' interface 
between a calling program - say, in PHP - and a database - say, MySQL. It 
is a 'least common denominator' approach which allows you to switch 
database back-ends with a minimum of trouble. It is less efficient than the 
native calls (in PHP: mysql_db_query(), mysql_insert_id(), etc.) and often 
does not allow you to use the special features of a given database. It 
should only be used (in my opinion, anyway) if you need to talk to a 
database where a native interface is not available. For instance, querying 
Microsoft Access from PHP. It can also be used as an abstraction layer, 
isolating you from differences in SQL from database to database, but there 
are other approaches to that. For instance, in PHP, you can use the PHPLIB 
library's DB_SQL (I think) class.

         - steve


+------------------------------------------------------------------------+
| Steve Edberg                           University of California, Davis |
| sbedberg@stripped                        http://aesric.ucdavis.edu/ |
|                                                          (530)754-9127 |
+---------------------- Gort, Klaatu barada nikto! ----------------------+

Thread
mysql, php and server...pons15 Jan
Re: mysql, php and server...Sasha Pachev15 Jan
  • Re: mysql, php and server...pons15 Jan
Re: mysql, php and server...Steve Edberg15 Jan