connecting to db..running a query

unknowngiver · 01-06-2007, 09:00 PM

Hey
i am reading an ebook on php and mysql..and here is how they teach to connect to a db:
????: NamePros.com http://www.namepros.com/programming/277976-connecting-to-db-running-a-query.html

PHP Code:

   $conn = mysql_connect("localhost", "joeuser", "somepass");

 
 echo $conn;

from reading other tutorials and looking at scripts..i learned that you dont need to define the mysql conection to a variable and echo it later on..u can just do:

PHP Code:

  mysql_connect("localhost", "joeuser", "somepass");

but which one is better? does it matter?
this is how they tell to run a query:

PHP Code:

   $sql = "CREATE TABLE testTable (id int not null primary key auto_increment,

 
 testField varchar (75))";

 
 // execute the SQL statement

 
 $result = mysql_query($sql, $conn);

 
// echo the result identifier

 
 echo $result;

Dan · 01-06-2007, 09:05 PM

If you are using multiple databases, you need to use a variable (such as $conn.) Otherwise, I don't think you need it.

echo $conn; would give you an error, too.

The ", $conn" in your third code doesn't need to be there. I don't know about $sql, because I'm not good at doing CREATE's in queries, but as far as I can tell, it's right.

unknowngiver · 01-06-2007, 09:16 PM

does it make it less efficient tho ?
and y would "echo $conn; " give me an error?

Dan · 01-06-2007, 09:46 PM

You'll get "Resource link identifier" or something if you try to do "echo $conn;". It's not really an error, but it's not really not an error.

I don't think using the MySQL link variable into the query does anything to do unless you are accessing multiple databases. I wouldn't worry about using it in queries, however I still would give the mysql_connect() a variable.

unknowngiver · 01-06-2007, 09:52 PM

Quote:

however I still would give the mysql_connect() a variable.

if u give it a variable..how would u execute it? by using the echo function? i am a lil confused here sorry :$

Dan · 01-06-2007, 10:01 PM

PHP Code:

  <?php

 
$handle = mysql_connect("localhost", "username", "password");

$db = mysql_select_db("database");

 
$query  = "SELECT * FROM internets WHERE site = 'namepros'"

$result = mysql_query($query);

$row    = mysql_fetch_array($result); // Lets just get one row from NamePros

????: NamePros.com http://www.namepros.com/showthread.php?t=277976
echo $row['something'];

 
?>

Of course that's just made up queries and stuff.. but you get the point.

unknowngiver · 01-06-2007, 10:03 PM

and that would work? wow yai lol

1 question...what if u were using multiple databases...how would u tell it 2 use the one u want it 2 use?

Dan · 01-06-2007, 10:45 PM

That's what "$conn" is for.

You would do $conn = mysql_connect... then something like $conn2 = mysql_connect...

To query the first database, you'd use mysql_query($query, $conn) and to query the second, you'd just use $conn2.

unknowngiver · 01-06-2007, 11:03 PM

okie got it

thanks

unknowngiver · 03-02-2007, 07:40 PM

Hey
I need this now..and i cant figure it out
the $conn stores the user information..not the database
so how do u tell it 2 use a specific database?
right now i m working a script where users can make and edit databases..and 1 is the Main database that they are using almost all the time..and then there are Databases that they make/edit/delete etc..
right now to connect and run a query i have

PHP Code:

          function MYSQLDB()

        {

            $this->connection = mysql_connect(DB_SERVER,DB_USER,DB_PASS) or die (mysql_error());

            mysql_select_db(DB_NAME,$this->connection)or die(mysql_error());

        }

        

        function query($query)

        {

            $success = mysql_query($query,$this->connection);

            return $success;

        }

so now..how would i make it that lets say..they want to edit a database called "db1" how would i make it do it?
????: NamePros.com http://www.namepros.com/showthread.php?t=277976
P.S: this is in a class..if it makes any difference

unknowngiver · 03-03-2007, 04:08 PM

Bump

01-06-2007, 09:00 PM	THREAD STARTER #1 (permalink)
unknowngiver Senior Member Join Date: May 2005 Location: Ontario Canada Posts: 3,088	connecting to db..running a query Hey i am reading an ebook on php and mysql..and here is how they teach to connect to a db: ????: NamePros.com http://www.namepros.com/programming/277976-connecting-to-db-running-a-query.html PHP Code: `$conn = mysql_connect("localhost", "joeuser", "somepass"); echo $conn;` from reading other tutorials and looking at scripts..i learned that you dont need to define the mysql conection to a variable and echo it later on..u can just do: PHP Code: `mysql_connect("localhost", "joeuser", "somepass");` but which one is better? does it matter? this is how they tell to run a query: PHP Code: `$sql = "CREATE TABLE testTable (id int not null primary key auto_increment, testField varchar (75))"; // execute the SQL statement $result = mysql_query($sql, $conn); // echo the result identifier echo $result;` __________________ Simplifying Engineering \|\| $$ Currency Converter $$ Julsh - Community/Dating Website \|\| Free Image hosting Fresh Proxies \|\| Random Proxy \|\| Troll Board

01-06-2007, 09:16 PM	THREAD STARTER #3 (permalink)
unknowngiver Senior Member Join Date: May 2005 Location: Ontario Canada Posts: 3,088	does it make it less efficient tho ? and y would "echo $conn; " give me an error? __________________ Simplifying Engineering \|\| $$ Currency Converter $$ Julsh - Community/Dating Website \|\| Free Image hosting Fresh Proxies \|\| Random Proxy \|\| Troll Board

01-06-2007, 10:01 PM	#6 (permalink)
Dan Buy my domains. Join Date: Feb 2006 Posts: 2,796	PHP Code: `<?php $handle = mysql_connect("localhost", "username", "password"); $db = mysql_select_db("database"); $query = "SELECT * FROM internets WHERE site = 'namepros'" $result = mysql_query($query); $row = mysql_fetch_array($result); // Lets just get one row from NamePros ????: NamePros.com http://www.namepros.com/showthread.php?t=277976 echo $row['something']; ?>` Of course that's just made up queries and stuff.. but you get the point.

01-06-2007, 10:03 PM	THREAD STARTER #7 (permalink)
unknowngiver Senior Member Join Date: May 2005 Location: Ontario Canada Posts: 3,088	and that would work? wow yai lol 1 question...what if u were using multiple databases...how would u tell it 2 use the one u want it 2 use? __________________ Simplifying Engineering \|\| $$ Currency Converter $$ Julsh - Community/Dating Website \|\| Free Image hosting Fresh Proxies \|\| Random Proxy \|\| Troll Board

01-06-2007, 11:03 PM	THREAD STARTER #9 (permalink)
unknowngiver Senior Member Join Date: May 2005 Location: Ontario Canada Posts: 3,088	okie got it thanks __________________ Simplifying Engineering \|\| $$ Currency Converter $$ Julsh - Community/Dating Website \|\| Free Image hosting Fresh Proxies \|\| Random Proxy \|\| Troll Board

01-06-2007, 09:05 PM	#2 (permalink)
Dan Buy my domains. Join Date: Feb 2006 Posts: 2,796	If you are using multiple databases, you need to use a variable (such as $conn.) Otherwise, I don't think you need it. echo $conn; would give you an error, too. The ", $conn" in your third code doesn't need to be there. I don't know about $sql, because I'm not good at doing CREATE's in queries, but as far as I can tell, it's right.

01-06-2007, 09:46 PM	#4 (permalink)
Dan Buy my domains. Join Date: Feb 2006 Posts: 2,796	You'll get "Resource link identifier" or something if you try to do "echo $conn;". It's not really an error, but it's not really not an error. I don't think using the MySQL link variable into the query does anything to do unless you are accessing multiple databases. I wouldn't worry about using it in queries, however I still would give the mysql_connect() a variable.

01-06-2007, 10:45 PM	#8 (permalink)
Dan Buy my domains. Join Date: Feb 2006 Posts: 2,796	That's what "$conn" is for. You would do $conn = mysql_connect... then something like $conn2 = mysql_connect... To query the first database, you'd use mysql_query($query, $conn) and to query the second, you'd just use $conn2.

03-02-2007, 07:40 PM	THREAD STARTER #10 (permalink)
unknowngiver Senior Member Join Date: May 2005 Location: Ontario Canada Posts: 3,088	Hey I need this now..and i cant figure it out the $conn stores the user information..not the database so how do u tell it 2 use a specific database? right now i m working a script where users can make and edit databases..and 1 is the Main database that they are using almost all the time..and then there are Databases that they make/edit/delete etc.. right now to connect and run a query i have PHP Code: `function MYSQLDB() { $this->connection = mysql_connect(DB_SERVER,DB_USER,DB_PASS) or die (mysql_error()); mysql_select_db(DB_NAME,$this->connection)or die(mysql_error()); } function query($query) { $success = mysql_query($query,$this->connection); return $success; }` so now..how would i make it that lets say..they want to edit a database called "db1" how would i make it do it? ????: NamePros.com http://www.namepros.com/showthread.php?t=277976 P.S: this is in a class..if it makes any difference __________________ Simplifying Engineering \|\| $$ Currency Converter $$ Julsh - Community/Dating Website \|\| Free Image hosting Fresh Proxies \|\| Random Proxy \|\| Troll Board

03-03-2007, 04:08 PM	THREAD STARTER #11 (permalink)
unknowngiver Senior Member Join Date: May 2005 Location: Ontario Canada Posts: 3,088	Bump __________________ Simplifying Engineering \|\| $$ Currency Converter $$ Julsh - Community/Dating Website \|\| Free Image hosting Fresh Proxies \|\| Random Proxy \|\| Troll Board

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