Newbie question ^_^

Anon

Just a quick question, why does this work:

mysql_select_db("databasename", $connection);

but this not?:

$db = "databasename";
mysql_select_db($db, $connection);

Whenever I try to use the $db variable I get a "No Database Selected" mysql_error.

[deleted]

Very odd. Are you sure you are using the correct var name (typo's) are you using the correct database connection?

Anon

LJ
It may need quotes
try $db = '"' . "databasename" . '"';

good day
gd

Anon

Yeah, the spellings are right and the connection is correct cos if I subsitute the variable for the name it works.

Anon

That results in the same error, 'No database selected'.

I did find that changing this:

$db = "databasename";
mysql_select_db($db, $connection);

to this:

define(db, "databasename");
mysql_select_db(db, $connection);

works tho. Does that explain to anyone why the first method didn't work?

mwilson

Hey,

Hmm, this looks like a case of mistaken identity, are you sure;

a) $db is spelled as $db in mysql_select_db
b) sure that $db is set to the correct database name
c) $db hasn't been used somewhere else (you're database connection for example?)
d) $connection is the real connection?

If you have done this correctly then it will work, the only possible explanation is human error.

Matt

Anon

I can understand that's probably the case but I just can't spot the error, here's the relevant part of the file (copied straight from it):

<?
// set up some common variables

// server name
$server = "localhost";

// username
$user = "test";

// password
$pass = "test";

// database to use
$db = "rhianan";

// function to insert a random quote
function quote() {
// initialise database connection
if (!$connection = mysql_connect($server, $user, $pass)) {
echoError("Error connection to database");
}

// select database to work with
if (!mysql_select_db($db, $connection)) {
    echoError("Error selecting database");
}

// execute query to select all the quotes
if (!$result = mysql_query("select quote from quotes;", $connection)) {
    echoError("Error running query");
}

// set $num_quotes to the number of quotes in the database
$num_quotes = mysql_num_rows($result);
$num_quotes--;

for ($i = 1; $i < $num_quotes; $i++) {
    $tmp = mysql_fetch_row($result);
    echo "$tmp<br>";
}
// seed with microseconds since last "whole" second
srand ((double) microtime() * 1000000);
$randval = rand(0, $num_quotes);

// get appropriate quote
mysql_data_seek($result, $randval);
$quote = mysql_fetch_row($result);

// show quote
echo "$quote";

// memory flush
mysql_free_result($result);

}

function echoError($errorString) {
echo "$errorString: ".mysql_error()."";
}

all i did to get this working is change the '$db = "rhianan";' line to "define(db, "rhianan");' and alter the mysql_select_db line accordingly.

b4 anyone points this out, I know it doesn't work properly (e.g. return a random record from the table) that's ok, i know this and will sort it later, at the moment I'd like to know why I was having this select_db problem.