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问题:
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I'm working on a system for my school that lets the teachers post any notices they have for the day on the intranet. However I got this error when testing it out:
Warning: mysqli_select_db() expects exactly 2 parameters, 1 given in C:\Users\Matthew\Desktop\wamp64\www\my-site\viewguestbook.php on line 23.
Here is the page's code:
<?php $host="localhost"; // Host name $username="root"; // Mysql username $password=""; // Mysql password $db_name="test"; // Database name $tbl_name="guestbook"; // Table name // Connect to server and select database. mysqli_connect("$host", "$username", "$password")or die("cannot connect server "); mysqli_select_db("$db_name")or die("cannot select DB"); $sql="SELECT * FROM $tbl_name"; $result=mysqli_query($sql); while($rows=mysqli_fetch_array($result)){ ?>
Note: This is different to the other questions of this same name on the website as it's in a different circumstance.
回答1:
The first parameter of mysqli_select_db() is connection object. This is the syntax :
mysqli_select_db(connection,dbname);
Change your code to:
$con = mysqli_connect("$host", "$username", "$password")or die("cannot connect server "); mysqli_select_db($con,$db_name)or die("cannot select DB");
Add the connection object as first parameter in mysqli_query and mysqli_fetch_array functions too. Please refer this link for the syntax.
回答2:
Change
mysqli_connect("$host", "$username", "$password")or die("cannot connect server "); mysqli_select_db("$db_name")or die("cannot select DB");
to
$connection =mysqli_connect("$host", "$username", "$password")or die("cannot connect server "); mysqli_select_db($connection ,"$db_name")or die("cannot select DB");
because mysqli_select_db needs the connection object as well.
回答3:
mysqli_db_select() method requires two parameters
So, you should pass connection object to the mysqli_db_select()
$host="localhost"; // Host name $username="root"; // Mysql username $password=""; // Mysql password $db_name="test"; // Database name $tbl_name="guestbook"; // Table name // Connect to server and select database. $connection = mysqli_connect("$host", "$username", "$password")or die("cannot connect server "); mysqli_select_db($connection,$db_name)or die("cannot select DB"); $sql="SELECT * FROM $tbl_name"; $result=mysqli_query($connection,$sql); while($rows=mysqli_fetch_array($result)){ ?>
